First Ride: Tantrum Cycles Missing Link Suspension

Jun 27, 2016
by Richard Cunningham  

Magic Link suspension
FIRST RIDE
Tantrum Cycles
MISSING LINK SUSPENSION

BY: R. Cunningham
The Tantrum Outburst is a 125mm-travel 29er with modern geometry designed to showcase Missing Link suspension.


Brian Berthold may not be on your short list of mountain biking's most notable inventors, but perhaps he should be. Berthold carved out a reputation as a capable suspension designer and crew chief in both off-road and Indy car racing. Then, mountain bikes caught his attention, and after a stint as a downhill racer, he started tinkering with suspension and brakes. Berthold founded Therapy Components, where he developed and marketed a beautifully made, inverted dual-crown downhill fork, followed by an aftermarket floating disc brake kit that was designed to eliminate unwanted brake inputs from the sometimes scary rear-suspension kinematics of the time. Fast forward about ten years, and Berthold again blipped the mountain bike radar when he invented a variable-rate/variable-travel rear suspension linkage debuted by Kona as the "Magic Link."
Tantrum Missing Link first ride
Brian Berthold poses with his Tantrum Outburst on Rocky Peak.


Kona Magic Link

The Magic Link was Berthold's first breakthrough invention in the cycling world. Using a simple linkage, Berthold created a rear suspension that, when pedaled, reduced the suspension travel to 100 millimeters and increased the spring rate - and would seamlessly switch to a softly-sprung, 150-millimeter-travel suspension the moment the wheel contacted a bump.

Berthold attached the forward swingarm pivot to a short lever below the vertically-mounted shock. Chain tension swung the lever forward, reducing the shock leverage rate and wheel travel, while bump forces pulled the swingarm rearward, which reversed the position of the link, increasing the leverage rate and lengthening the suspension travel. Berthold used a small spring to hold the linkage in the short-travel pedaling mode and to control the action of the transfer between long and short travel modes.

Berthold's Magic Link was a simple, mechanical method to address the need for a firm-pedaling, long-travel rear suspension, but it did not catch on. Kona's rough execution of the concept was partly at fault, but Magic Link was ahead of its time - all-mountain and enduro bikes were still over the horizon, and the novel-looking Magic Link was neither well understood, nor well received by the press at the time.
Air Spring side full
Kona's Abra Cadabra was the last of its Magic Link models. Chain tension and bump forces from the swingarm toggle the lever below the shock - forward to reduce and stiffen, and rearwards to lengthen and soften the suspension's travel. The tiny air spring connected to the lever adjusts the sensitivity of the Magic Link as it switches between modes.


Berthold's Missing Link

Undaunted, Berthold maintained that the ultimate long-travel trailbike suspension should pedal perfectly, provide traction on uneven surfaces, and absorb bumps - all without employing electronics, remote levers, or compromised damping effects. He further simplified the basic elements of the Magic Link, eliminating its spring-loaded control mechanism, and ended up with an elegant solution that employs two naturally opposing forces on the swingarm to either activate, or to completely lock out the shock. He dubbed it the "Missing Link," applied for a patent, and began to search for a bike brand in need of new suspension technology.
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Tantrum Missing Link first ride
At full extension (illustrated here), the two links that drive the shock are aligned vertically. They essentially become a fixed column that mechanically locks the suspension. Until the rear wheel contacts a bump and levers the two links out of position, the Tantrum is truly a hardtail. With rider aboard, however, the shock sags into its travel like any other suspension. While riding, the Missing Link only locks out in response to chain tension generated when pedaling.


When Berthold paired up with Kona, long-travel trail bikes were not the rage, so the Magic Link was a hard sell. Later, after he developed the Missing Link, enduro was raging and the average trail bike was pushing 150 millimeters of wheel travel. It was a perfect storm, and Berthold assumed that his simple mechanical solution to the genre's "perfect pedal/perfect suspension" conundrum would be snatched up by a number of forward thinking brands - but he found no takers.

"Each time I showed the Missing Link, the response was the same," said Berthold: "It works great, but bikes are pretty darn good right now and we don't want to allocate the time and expense to develop a new suspension." Berthold threw up his arms. "So, this is it? Bikes can't get any better, so we all should just stop trying to improve them? That's weak!"

Tantrum Missing Link first ride
The swingarm attaches to the Tatrum's Missing Link. The swingarm only moves a few millimeters fore and aft to activate the link.
Tantrum Missing Link first ride
Conventional seatstay pivots and a bolt-on dropout/caliper mount assembly that future-proofs the frame against new hub or axle standards.


Tantrum Cycles

Berthold then took a more direct route to bring his Missing Link suspension to the marketplace. He put on his Mechanical Engineering hat, switched on Solidworks, and designed two welded-aluminum trail bikes: The Meltdown - a 162-millimeter-travel all-mountain/enduro bike based upon 27.5-inch wheels, and the Outburst - a more trail-oriented 125-millimeter-travel 29er. Using his own money and contacts he had previously worked with in Taiwan, Berthold founded Tantrum Cycles, which will be selling direct to customers as soon as July.

Missing Link
I rode the Meltdown - a 160-millimeter chassis with 27.5-inch wheels, and geometry that fits squarely within current all-mountain/enduro trends.

bigquotesSo, this is it? Bikes can't get any better, so we all should just stop trying to improve them? That's weak!

The idea is to sell some Missing Link bikes, get his new suspension system under some riders, solicit some good press and hopefully, make a little money in the process. Berthold says that Tantrum initially will only sell frames, which makes sense, considering the massive investment required to produce complete bikes. If all went well, Missing Link could gather enough momentum to nail down a licensing agreement from a reputable brand.

First Ride on the Missing Link

When the first production frames arrived, Berthold gathered up enough components to assemble a Meltdown and an Outburst, flew to California, and invited me out for an opportunity to ride the bikes. I chose a zone north of Los Angeles that would exaggerate the strengths or weaknesses of a good cross-country bike as well as a pedigree enduro machine. Lots of rocks and dust, technical ups and downs, extended climbs, and speeds that varied from suffering upwards at a walking pace to mach chicken descents.

I rode the Meltdown, partially because, with a bit more than 160 millimeters of suspension travel and 27.5-inch wheels, it was more representative of the present market, but mostly because I was curious to see if a trail bike with that much squish could actually sprint and climb like a hardtail. Heard those words before?
Tantrum Cycles

Tantrum Cycles

Setup: Brian suggested that I set the suspension without factoring in pedaling firmness. That may seem like stating the obvious, but it reminded me that most of us fudge our spring and damping settings a little to ensure that the bike will pedal well enough in the open settings to cover the many moments when we can't reach the lever on the shock. I chose somewhere between 25 and 30-percent sag for the shock and 20-percent for the fork, and I adjusted the rebound a little fast in anticipation of the quick, chunky descents ahead. Both bikes were outfitted with X-Fusion forks and shocks, which tend to deliver a firm ride in any setting, so I didn't know what to expect when we rolled up to the trailhead.

Climbing and pedaling: Turns out that the Meltdown actually did feel like it had a rigid rear end under power. Beyond the fork compressing, there is no suspension penalty for jumping out of the saddle and pounding on the pedals with abandon, and seated pedaling feels equally efficient. Sweet, but after being briefed on the Missing Link, I expected that. What I didn't expect, was how seamless the suspension kicked in when I was fighting my way up the trail's technical rock problems. I was sure that the linkage would feel notchy as it unhinged back and forth from completely rigid, to a decidedly plush 160-millimeter rear suspension. Berthold explains that the scissor-action of the two links initially creates a falling leverage rate, which maintains some pedaling support as the suspension transfers from rigid to plush mode.

Descending: Both bump forces and rear braking uncouple the Missing Link, so the Tantrum's rear suspension is never locked on the downs. In fact, the suspension sags farther into its stroke at speed, which lowers the bike's ride-height slightly, slackens the head angle and adds a measure of stability. Whether the Missing Link returns to full rigid when pedaling out of corners is not apparent, because the chassis feels consistent. Theoretically, the rear end must rise slightly under power because the shock is pushed towards full extension, and I could feel that happen while I was climbing, but I did not sense that occurring at any point while I was descending.

Observations: I noticed that the fork was overdriving the rear suspension while I was at speed and working the bike hard over the zone's chunky sandstone. Much of that could be attributed to the X-Fusion fork, which performed poorly over sharp-edged impacts. The harsh feeling fork probably exaggerated the tendency of the rear suspension to settle into its stroke, so potential customers should choose a fork that is suppler in the pointy bits.


First Impressions:
bigquotesBrian Berthold's Missing Link delivers the goods - direct drive pedaling with supple suspension action - and it does so without electronics, remote levers or voodoo shock damping. Compared to the current crop of carbon superbikes, the Tantrum Meltdown looks rough around the edges, but it performs well on the downs - essential for any 160-millimeter trail bike - and its pedaling action is better than all of them.

Bold statement? I've ridden many trail bikes that were supposed to, '...pedal like a cross-country bike and descend like a DH bike.' (I've written that phrase more times than I should have) Only two have actually performed that ballet: the Meltdown with its Missing Link, and a Kona Process outfitted with Fox's prototype Live Valve electronic suspension. Neither are perfect, but both set the bar well above today's crowded pack of carbon uberbikes.

Send the Meltdown to finishing school, add a better component selection and a more sophisticated fork and shock, and I think it has the potential to take on the big guys. Brian Berthold's Missing Link is proof that there actually is significant room for improvement among the present crop of all-mountain trail bikes. Cheers to thinking outside the box. - RC







350 Comments

  • + 230
 First thought when i saw the Tantrum bikes: maaan, these things are ugly! Now that i read about them, the suspension, the man behind them, his story, i begin to respact the man and his efforts. Come to think about it, the bikes do begin to grow on you. Smile
  • + 11
 Exactly.
  • + 81
 you can respect the hell out of the man and the machine while still thinking the paint job is ugly.
  • + 18
 in fact, if this dude is reading the comments, ill trade design for a bike...
  • - 26
flag giant-35 (Jun 27, 2016 at 14:50) (Below Threshold)
 the thing for me is how many pivots you would have to grease
  • - 18
flag Downhill29erplease (Jun 27, 2016 at 15:13) (Below Threshold)
 I think the bike would look significantly better with a new front triangle design, currently it looks like a weird commencal meta sx. Similarly to how I think yetis switch infinity only looks good with their front triangle.
  • + 35
 I'm Impressed. He made some bold statements about this bike, and I'm now super curious... When I'm in the saddle, I have no idea what my bike looks like, so it's peculiar appearance won't keep me from pursuing it . If that bike truly rides the way he expresses it to be-- a little love in the finishing dept. and I'm down to ride that beast!
  • + 13
 @diggerandrider: yep who cares strip the paint and let it go...
  • + 7
 Very interesting design and looking forward to test one asap.
  • + 10
 Anyone else digging those skin walls?
  • + 7
 @lyophilization: it is just paint. ...easy to have a custom job done that could really look sexy
  • + 17
 Sounds radical, but the way this suspension sounds to work, 8" enduro bikes could be right around the corner. Very exciting if you ask me.
  • + 6
 It's true: the graphic design is cringeworthy. It's not the point, but Berthold would have an easier time making his point w/ a less fugly look.
  • + 2
 When i said the bike's ugly, i didn't mean the paint is ugly. I meant the placement of the shock. The front triangle's fine, the paintwork is on par with most of the other brands, it's just where the shock is sitting that is a tough pill to swallow. But it does get to you in time. And the man's explanations about the suspension design - extremely interesting! Smile
  • + 4
 I'm with you @hitarpotar the idea of a better pedaling platform is what we all want. Beauty is in the eye of the beholder. I'm surprised to read this review by RC and the description of the actual ride being as good as it is and Tantrum is doing it with Xfusion, nothing against them but they aren't one of the expected two suspension companies. I hope this bike shows up at Interbike. N+1
  • + 1
 I really respect the guy, because it is a very clever design. However, this design is already sentenced to death, because of "Fox's prototype Live Valve electronic suspension" and alike ... Electronic system will be cheaper to produce (BUT retail prices will be high), and will be much more expensive to service (or to replace whole parts really), which means double profit for suspension companies.
  • + 0
 One of my life rules is to never trust anyone with a soul patch/goatee but I might make an exception in this case. Make a 140-150mm 29er please!
  • + 6
 @chize: Ok, I have a life long rule to never HAVE a goatee or soul patch. I'm not sure what this is. My wife has a name for this, I can't print here. she calls my sideburns a faceknife. But I met her when I had half a beard. Just havin fun. I digress.

I just put a 150 mm fork on the 29er. Fun. Even more fun with the 165 mm 27.5 rear end on it.

We might squeeze a little more out of the 29er rear end, but not for 2017.
  • + 1
 @tantrumcycles: Haha looking closer there is a lens smudge on the picture of you that looks like a goatee. Just giving you a hard time, i'm a beard guy myself.

I do like the idea of 165mm 27.5 rear and 29 front, sounds like a lot of fun
  • + 1
 @tantrumcycles: Any plans to make an XL size? i'm only seeing s,m,l on your website
  • + 3
 @chize: I had a full beard for 20 yrs. Then decided to have fun with it. It could change at any moment, possibly in an unconventional direction.

Sizing is in fluz. S, M, L will be Short, Med and Long. I'm going to stretch the reach as much as I can between sizes, while keeping relatively short ST. The new L is 460 mm reach

The 29/27.5 combo has the big wheel rollover in front, where you need it. It also has the long travel bump gobble in the rear, because sometimes, you just have to hit stuff with the rear. The smaller rear wheel also makes the handling a bit quicker, more fun, but the bike is more stable due to the travel.
  • + 2
 Agreed, it's a 90's flashback, or maybe 200 and one. That said, technical innovation is the success here, not the facade (emphasis added).

Tantrum only as four followers, me being the forth. www.pinkbike.com/u/tantrumcycles Let's see what this guys bright future has in store! Cheers to Brian for not sticking with the status quo!
  • + 0
 Asthetically if the seatstays lined up with the top tube, this would be a very pretty bike. The linkage is complicated but gorgeous, but the top "big" link sticks out into space like a Kona or Ellsworth circa 2003. If it had more clean lines, space for big tires (like 3.0) and frame wasnt too heavy itd probably sell really well.
  • + 3
 @PHeller: Thanks for the comments. The bikes will fit 3.0 tires and have a boost dropout available along with 142.

Complete weight as tested 29 pounds with pedals. The frame with no shock is 3232 gms, about 7 lb, 2 oz.
  • + 1
 @tantrumcycles: Brian, I'm impressed with what you've accomplished here kinematically, but I wonder how much the pivot and forward shock eye locations could be moved before the system no longer functioned as designed. As you have no doubt learned through trial by fire, aesthetics matter to market acceptance. I can see this system gaining rock star status with a more horizontal shock orientation, a straight left-side chain stay, and (again with the horizontal) less steeply pitched seat stays. How much have you played with those possibilities?
  • + 2
 @Magellan35: Thank you kind sir.

I'm not saying they can't be moved, but that's for future development. I had run thru hundreds (if not thousands) of iterations of moving points by the mm, to get all the right reactions in the right directions. i do know this, in the current configuration, if you move things by much ( a couple mm), things get wonky in a hurry. That's one reason that I'm so amused by those making definitive statements of poorly scaled photos.

This is my 4th iteration in metal, making fine tuning changes along the way. It's pretty dialed, performance wise and will go into production this way. One advantage of this layout (as opposed to the horizontal shock) is a lower CG. All the sus parts are LOW.

The CS, wrestled with that forever. I used the straight LS CS on the g2 Magic Link bikes, but, I don't like the asymmetric look (or potential feel when landing from a jump) and it makes the CS bridge a mess and takes away some stiffness due to that.

As for the SS, the frame is a M/S, so on the new Med, they'll be more in line and on the large, they, be a bit under the TT. So, it's hard to make that line up with all frame sizes.

Thanks for the comments, I'm sure in the future I'll discover plenty of new possibilities. Not done yet.
  • + 1
 @tantrumcycles: Thanks for getting back to me. Full disclosure: My company is in the final design phase for an enduro bike of my design. At the moment I'm using a well-tuned Horst variant for the rear after kicking around virtually everything in the marketplace, but I'm extremely intrigued by your design.

After reading this article, I actually laid out a version of your rear with more horizontal shock and SS placement and mocked it up in the shop using MDF. The system functioned (as well as could be expected in MDF), but I'm sure axle path, shock tune, orientation, and length can quickly become issues (wonky, like you said). Very intriguing. Are you still interested in licensing the rear or co-developing the design further? (We're doing virtually everything in carbon)

Regardless, I wish you all the best growing your brand. I have some idea of the challenges you've overcome to get this far, and I hope I get to ride a Tantrum in the near future.

Cheers,
Lon
  • + 2
 @Magellan35: Wow, didn't expect that. If a modified carbon Tantrum-Magellan version with a more horizontal shock comes out, it's gonna be crazy good!!! Smile Come to think about it, the name does sound good to me! Hah
  • + 1
 @hitarpotar: I'm in touch with Brian by email, and am seriously considering a trip to Tantrum HQ for a ride. The only thing holding me back at this point is that we're just about to tool up for production, so it's awfully late in the game to revise the rear end.

You never know, though...
  • + 1
 @Magellan35: Any word on your company's design??? Details? Smile
  • + 2
 @hitarpotar: Not quite yet. We're keeping everything very much on the DL until production tooling is complete and we're about ready to produce bikes. Then we'll do a proper spread in a magazine timed to coincide with publishing of the website, videos, rider testimonials, social media, etc.

Hint: 27.5" carbon enduro, 150+mm travel, 344mm BB, 65° HTA, and a 1200mm whelbase in a size L that still has reasonable reach numbers. Eagle X01 and Super Deluxe RC3 trunnion in a bike built in the Canadian Rockies to take on all comers in enduro racing. That's all I can reveal for now... ;-)
  • + 2
 @Magellan35: let's do it
  • + 2
 @tantrumcycles: innovative stuff. Really looking forward to see where this design ends up.
  • + 3
 @inverted180: thanks Inverted. We just got our kickstarter launched:

www.kickstarter.com/projects/812273700/tantrum-cycles-the-missing-link-in-full-suspension

Really great response so far. Still have frame/shock starting at $1400 and completes starting at $2600. Special kickstarter deals
  • + 1
 @inverted180: Brian is a hell of a nice guy, too. We've continued our conversation off Pinkbike, and it's fair to say that innovation is far from dead. Where the bicycle will be by 2025 is a tough call, but it's fair to say it will be meaningfully improved over the ho-hum efforts we've all seen in bike shops for the past several years. Brian is leading the charge. Buy a Tantrum and see.
  • + 87
 "Brian Berthold's Missing Link is proof that there actually is significant room for improvement among the present crop of all-mountain trail bikes."

Did PB just try and set up up with that poll earlier?
  • + 109
 It was Brian's comment that inspired me to write that poll.
  • + 24
 Yup those polls are collecting market data for free from it's members to sell to companies.
  • + 46
 @NorCalNomad: pinkbikes gotta pay the bills. Writing and web development doesn't come free.
  • + 3
 @NorCalNomad: Maybe but also they create a mindset, 'prime' the audience to elicit a specific response. You read it a few days ago and it lingers in your subconscious by now and now you are rady to take the bait ; ) Richard put on the spin doctor hat. You never know which he is going to wear next.
  • + 16
 @mattl1989 Exactly. I couldn't believe that SO many people thought that things couldn't get significantly better in the coming years. Seriously? Bikes now aren't awesomely better than bikes from 2006? The difference in bikes & components has greatly advanced since then. Same in the ski industry. Same in many others. We all thought the bikes from 2006 were amazing at the time. But no one would trade their current 2016 bike in for one from 2006. The same will be said in 2026. And if this suspension design is anything like it claims to be, then we are in for a real advancement.
  • + 18
 @hamncheez: I like the polls, it means that you get to see what other riders around the world think and how opinions vary
  • - 64
flag mhoshal (Jun 27, 2016 at 14:54) (Below Threshold)
 @ka-brap: I could just use my monarch xx with remote lockout to achieve the same thing this bike apparently does but only when I want it to not when it wants to. Not very ground breaking if you ask me.
  • + 31
 @Sontator: Dude, if you're spending time on pinkbike for free then you probably shouldn't complain about some optional poll that you don't even have to take. If you don't want to be influenced by marketing then you're going to have to stay off the internet.
  • - 63
flag mhoshal (Jun 27, 2016 at 15:12) (Below Threshold)
 How the hell do you negative prop a guy for giving you facts lol f*cken noobs on here are a total f*cken joke. The rest of you are cool though!!!
  • + 14
 @NorCalNomad: If you aren't paying for it, you're the product.
  • + 2
 @hamncheez: you all don't know PB sell stickers for $20.00
  • + 4
 @RichardCunningham: & here I just checked the box that said "No. Expect small geometry tweaks and minor weight reductions." Well played RC, well played Wink
  • + 9
 @RichardCunningham: ...see that? Right there. A gif/vid of the rear end working. THAT'S what I'm talking about. ALL reviews should have this
  • + 1
 @NorCalNomad:
Or companies can sign up for a free account, answer the polls and then receive said data, instantly, for free.
Not sure if there is a flaw in your argument there somewhere?
  • + 1
 @WestwardHo: Apologies if it sounded like complaint. It is admiration for creative genius that is not limited to designing bikes but extrnds as far as marketing.
  • + 1
 @cooperquinn-wy: dude that's deep
  • + 1
 @ka-brap: They are not really ... My Mojo Classic was not that much better that my current HD3. Jokes to the side, the only difference is a slightly slacker geometry, shorter stem, and maybe pedaling a bit better.
  • - 10
flag mhoshal (Jun 30, 2016 at 11:47) (Below Threshold)
 Lol alot of fags on this site at least 57!!!!
  • + 48
 would love to try this and props to Brian Berthold for staying with it despite not getting industry support
  • + 8
 Crank Bros should produce it! Oh wait...
  • + 3
 @bishopsmike: - after working in LBS's for too many years I cringed whenever someone wanted to purchase a CB product, however it seems they are fully aware of the rep they have "earned" over the years and are actively addressing quality/durability. That being said I have no plans on buying anything from them in the future until it's proven that the quality issues have been corrected
  • + 34
 Glad to hear it gave good traction on the technical climbing. I get annoyed with folks who want a hardtail's climbing characteristics on every climb, ignoring that suspension has a big role increasing traction while climbing rough stuff. To be clear, the fork wasn't bad just because it's X-Fusion, it's more because XF's RL2 damper with mid-valve is notoriously harsh on repeated fast hits. Their Roughcut HLR damper is a huge improvement for that type of terrain, and their forks' chassis are top notch in general.
  • + 7
 @lazarus2405 so true...I can't stand climbing anything other than fireroad with a locked rear/HT
  • + 15
 @nvranka: 29er hardtails climb pretty well!

............ill let myself out ;-)
  • + 4
 To those reading you can now upgrade your rl2 damper to roughcut for $200.
  • + 4
 It's like saying rockshox sucks because the domain you rode didn't feel good.
  • + 10
 Or like saying fox sucks because you bought a 2013 fox product.
  • + 34
 Not the sexiest thing ever, but it seems that it gets the job done. I'm all for it!
  • + 31
 I'm not smart enough to design anything like this and it sounds pretty rad, but I would: 1) Make an XL frame as I stopped reading this article as soon as I saw the geometry chart 2) Not release those graphics on the production bike. Ever. There's something timeless about an anodized finish and understated graphics.
  • + 8
 Yeah these companies just don't make bikes big enough to anymore! I'm 6'4 and there are companies out there calling frames XL's with the geometry of what I would consider a large. So many bikes I've wanted to try over the years but I can't go putting myself on a small frame. These companies need to realize that not all mountain bikers are 5'10 and start making bikes for tall guys. That would be my only improvement to the bike industry. It's sad really.
  • + 1
 Well, looks like the 'Large' Size is really, really close to a Rocky or Trek XL.....I think a 5' 10" guy would feel a bit small for the larges here.
  • + 26
 Hi all, I was on the road so a little late to the party here. A little blown away, actually. This is brian. Thanks to all who commented and emailed, etc. Even the haters, it's been a blast to read. And eternal thanks to RC, for being willing to entertain the notion that maybe, just maybe, we haven't seen everything yet, and even further, for giving me the time of day to take me on an awesome ride. I'd mention it here, but maybe he wants to keep it secret.

As RC mentioned, the ride had it all (including me pushing a LOT). But it was a great acid test of EVERYTHING. Some components faring better than others. As belabored, the fork was a little overmatched. As was pointed out, this was more of an entry level fork that was graciously loaned to me (thanks Joel ), so that I had something to attach the front wheel to (thanks Len). I explained to RC that the build of the bikes was indeed a mix of components that we were testing for possible inclusion into a lower and/or higher priced spec. All of the components were pretty much competitive market products worthy of consideration.

I wasn't that concerned with how much the overall component mix affected the perception of the bike, as my engineer brain said that everyone would just focus on the suspension. I think, for the most part I was right, with the glaring exception of no dropper post!!! and graphics. and fork. and the aluminum frame. Thankfully, RC was graceful in his criticism, realizing my lack of presentation skills. When we offer build kits, they will be dialed.

Graphics. For the first time in my life, I hired a high zoot, well regarded artistic graphics team. Except for the head tube badge, for which I blame myself. I told the graphics team it was a show bike, make it stand out. It sure worked. In reality, it is not mass production friendly and will be simplified. I have 2 versions being worked on by new people. Who knows? See at Euro/Interbike. The HT badge stays.

I'll try to answer some of the more pertinent questions in the thread, but it's long, so feel free to ask.

b
  • + 5
 Thanks for responding! Love the information and explanation about the process. Wishing you only the best in the endeavour and I am excited about this mechanical innovation! Your perspective on it all is great... Hopefully I can ride one someday and see what I think!
  • + 1
 @burnbern: thanks. stay tuned.....
  • + 2
 Hi Brian,

It looks like you have done something really interesting here and could be a big hit with certain riders.

One thing I would say is that the geometry is outdated and I think if you are going to sell a decent number of bikes, they need to have longer reach and TT measurements.

If you tweaked this and a few other bits (as mentioned the graphics) and make the link more aesthetically pleasing I think you will be on to a winner.

As it stands a 20" ST with a reach of 440mm is just too outdated for most people to jump on board. I am 6'3 and ride a 19" bike with a 485mm reach.

Ok my bike is at the extreme end of the spectrum, but something in between the two would stand a better chance of selling more bikes.

I think it would be a shame to have such an well though out and innovative bike, being held back by such conservative geometry numbers.
  • + 2
 Thanks for stopping in Brian!
A far as an early production/test mule goes, I don't think you have to put any effort into getting us engineers and engineering types to look into the merits of the design, and details of the bike. That's in the bag.
I think investing in a bling heavy (at least where it is visible) T&E / technology demonstration bike would be worth it, especially in occasions like this. The frame-only market is dominated by internet and bike shop denizens who are meticulous about sourcing high end stuff, and being reliant on what parts you can borrow means something as simple add having the RL2 damper in that fork colors even a highly favorable review of the complete bike.
It actually means a lot to see how unconcerned you personally are with decking out a press bike with expensive parts to make the point about missing link being an excellent platform, unfortunately I'm in the minority regarding that outlook.
TL;DR: I think a press bike with bare aluminum and understated anodized finish to look like a test mule, but spending money on a Fox 36, high end dropper, and XT drive train would be a very worthwhile investment.
  • + 3
 @kudos100: I mentioned elsewhere, new geo. I'll post the new chart soon.
  • + 3
 @tehllama: I do want to clarify what I meant when I said I was "loaned" the forks and wheels, etc. All of these parts were sourced from the representative companies. The individuals I mentioned work at those companies and I was trying to give them a shout out. I was asking for parts to evaluate for consideration of inclusion for build kits, both high and low end.

So in my "tester mind", I always have to separate the effects and try not to let one components ruin the evaluation of another. I do realize the folly of this in terms of the market place, and certainly in the case of the fork, it is obviously going to affect the action of the rear. But I do want to be able to sell a more affordable build kit, so I need to be aware of all of the options.

So, I really didn't look at this as a "press bike". And we're not selling complete bikes, or even build kits yet. Bad timing for this test to have that fork? Yes. Dumb move in retrospect.

But I'm happy that RC is also a tester and can separate that (to a degree) when evaluating the suspension.

We'll have the chance to test the complete bike this fall, all blinged out.
  • + 1
 @tantrumcycles: Glad to hear, I wish you all the best with this, it seems like a genuinely innovative design, unlike the garbage new standards and 'innovation' we are fed every few years by certain big companies.
  • + 3
 I like how different the linkage looks personally. Only thing that sticks out to me is the fact the shock goes into the downtube probably limits what shocks can be used. Not a fan of the graphics (I'm an artist, to each his own) but I love the head tube badge, its spectacular definitely keep it!

I also appreciate your desire to offer more affordable build kits, or builds as unlike most (it appears) on here I have a very limited budget to spend on my biking passion.
  • + 1
 @kudos100: how 'bout a reach of 460 on the L?
  • + 4
 @guategeek: Shock use will be limited, but, the supplied shocks will have a unique valving package optimized to the design.

i'm lukewarm on the exisitng graphics, which I outsourced (except the HT badge). Got now guys working on new graphics. Who knows? But the HT badge stays.

I do want people to be able to afford the bikes. If I can offer good value at the weight of a carbon bike at a lower price.........
  • + 1
 @tantrumcycles:

That sounds in the right ball park for modern geometry Smile

If I was in the market for a 20" frame, I wouldn't go for anything less than 460 reach and maybe a tad more.

Most people will be happy to go a bit shorter on the stem than 50mm, but the amount of people who will ride longer than 50mm is becoming smaller and smaller.

This article is worth a read if you haven't seen it: www.mbr.co.uk/news/size-matters-why-were-all-riding-bikes-that-are-too-small-321374

While I think Chris Porter is pretty extreme and I don't agree with everything he says, some of what he talks about makes sense. A lot of companies are moving towards longer reach figures and within reason, makes for a better handling bike.
  • + 1
 @kudos100: CP makes some good points, but there are other factors at play as well, that people aren't even thinking of. One thing that's driving the movement toward longer reach, is the drive toward shorter CS. One of the big victims of shorter CS is ST location/angle. You simply run out of room for thew wheel at full travel with short CS and are forced to use a steeper effective ST angle, which moves the saddle forward relative to the crank. To maintain a decent TT length (and therefore seated reach), you must increase the classical reach number (between crank and HT).

For each ST angle/TT length, there can be only 1 possible reach. But for any given reach number, there are an infinite number of ST angle/TT lengths that can achieve that.

I do agree with one important point CP made. Why only 10-20 mm difference between frame sizes? We are trying to fit riders with maybe a 10" range in height with a range of maybe 3 or 4 inches in reach.

Toward that end, I am pushing 30 mm reach different between my S, M and L, 400, 430, 460. Is it enough? Is it enough for 6'4" rider? I don't know, but I will say, that with my slacker ST angle, the effective TT length will be longer than for a similar reach measurement.
  • + 1
 @tantrumcycles:

Yes I think that is the one thing I think most people agree on. Reach numbers have been too conservative for a lot of bikes and companies are starting to wise up and make longer numbers between sizes.

I think you could bump it up by +5/10mm which would one; give taller riders 6'3+ a chance of fitting on a L without a long stem (lots of people won't run a stem longer than 60mm on a trail bike now), but also give those in between sizes, the chance to run a shorter stem if need be (35/40mm)
  • + 1
 @tantrumcycles: Also, one other point that I think is worth considering is that, it could be worth chopping half an inch of the ST length. 15.5, 17.5 and a 19.5

I have an inside leg measurement of 35" and can easily ride a 19" frame with a 150mm dropper.

Having slightly smaller ST numbers would again give a bit more versatility between sizes due to difference in leg lengths and that most people run a dropper these days.
  • + 1
 @kudos100: one reason I'm calling it short, medium, long. I figure I am using a shorter ST size, which droppers make more plausible. I think 460 is at least at the longer of average for a 20" ST. Trying to bridge the gap between L and XL, while keeping the medium around 430.
  • + 1
 Good on you and good luck!!!!
  • + 24
 Why are people so pissed about the looks? It does what it says it'll do and well apparently! I hope these frames aren't expensive, because I want one now!
  • + 19
 It's legions of newjacks who hold a stealth nomad at the top of all things aesthetic.
  • - 4
flag poozank (Jun 27, 2016 at 14:22) (Below Threshold)
 @Pennyrisk: Nomad is the best looking bike though, no question
  • + 5
 @Pennyrisk: newjack city?
  • + 5
 @Pennyrisk: so you dont mind if i paint your car bright orange with scribbles all over it?
  • + 1
 It looks really bad, like a department store bike from the 90s. I'm all about things that look different and color is one of the last things I look for in a bike but you have to draw the line somewhere lol.
  • + 4
 The looks are very dated and amateur. I'm biased as I work in the design industry, but I do think aesthetics play an important role in establishing a solid brand identity which can help lead a company to success if all the other parts are in place. That's a big if—you can't rely on graphics and marketing along to propel you to success, but if you've got an awesome bike and wicked employees, the right distribution, good price point, and so on, it really can't hurt! I personally really like this frame design, if they cleaned up their image a bit it could really help, but he might not need to do if he strikes a licensing deal with a larger bike company, they'll just integrate the frame design into their current branding anyway. Which I really hope happens, I've got a Kona CoilAir (magic link he designed) that I really like so I'm damn curious about this suspension design!!
  • + 5
 @lyophilization: Sure, then it'd match my Rune Smile

@spectacularspectacles Aesthetics are very important, but so is creativity and uniqueness. I would suggest that the look of their bike is establishing a solid brand identity. I must admit that yes, SCs bikes do look great but there are also plenty of bikes that look as good with much more character. I value character above all - in fact the most badass bike I think i've ever seen is Cam Cole's Ellsworth from a few years back, it just screamed fast and brutal.
  • + 17
 "The Bikes right now are pretty good and we don't want to put the time effort and money into new suspension ideas/systems."

If I had to guess, that's more of a "We are making a lot of money off of what we're doing right now and we're too greedy to change anything cause we like making money."
  • + 1
 Or it's actually "we can archieve a better or equivalent anti squat and leverage curves with two less axles in our design so we don't see the point of this thing"
  • - 3
 @faul: Nailed it ^^^^^
  • - 2
 @faul: No they do not. Simply because in "traditional" suspension antisquat ALWAYS makes suspension much less active. This design separates antisquat from suspension action and this is the primary "feature". This is something completely different than "traditional" antisquat or compression-based platform in a shock.
HOWEVER, this design will not succeed, simply because the same can be achieved with electronics. And we all know that if something can be done with electronic, it eventually will be. Because in the end electronics are cheaper to produce, you can put a lot of gadget-like features AND electronics fail faster, so you earn more money on service.
  • + 11
 @lkubica: hi lkubica...thanks for recognizing that anti-squat curves are not the be all end all that some people want to represent. And that my design does things differently. That is a key point that people have difficulty accepting.

However, I will continue to believe there will be a market for a non-electronic based solution. True, someday, there will be a bike with electronic front and rear sus, shifting, dropper, braking, maybe even drivetrain!!!!. But, I would like to market and sell a mechanical device that does it more simply, for less money.

I think there are people with me on that
  • - 2
 @lkubica:
Actually, the anti-squat wasn't my point. I only wanted to say that this design isn't really magical and it's close (or not very far) to existing designs, because it has a fixed axle path (or other parameters that go with it, like IC potition curve, or whatever you need for your analysis) and a fixed leverage curve, so it works like any other bike. only the compromises are differents. There is no magic in bike kinematic, as soon as you have the leverage and the axle path, you can forget all you know about the pivots locations, the shape of the links, or whatever, and write the matrix describing the reaction of the chassis to every force you need (in 2D analysis without thinking about the flex)(matrix will also show where goes the energies). The matrix of this bike will have the same size as the matrix of every bike that has one shock (bikes that have one degree of freedom when shock is removed).
And, when you have this matrix, you can try to obtain a close or similar matrix with a more conventional design, the bikes with close matrix will have as close riding characteristics.
And "anti squat" here will have the same effects as every bike with one shock in the rear suspension, but as "anti squat" is, in my opinion, non-relevant in bike analysis, you actyally can't say anything about it.

@tantrumcycles
no, your design actually does thing the same ways, only the compromises you used are different. I read the beggining of your debate with "Vrock", in the link here in the comments and saw your videos. and I can say that your bike may work as you say, but not for the reasons you mentionned. You can argue that the anti squat doesn't represent many things, but you can't say the same logic don't apply to your design, as the physic won't change.
Like, if I apply classic rules. "if the chain tension lift the bike, there is loads of kickback". So does your design have loads of kickback? Yes, It has. Just see the video you posted when you actuate your suspension without the shock: you see the front pedal lifting under suspension action. And when you push on the pedal the suspension lift (or doesn't fall). Like it would be with high "anti squat", "chain growth" or "IC heigh" values, the same rules with any other bike with a similar matrix applies.
I digress and I don't think I'm saying everything I want so I will stop here.
I think Your design may have potential, it surely works well in the "more travel that works like less" category, and many buyers will be happy. But please stop hurting physic.
  • + 5
 @faul: Mr Faul. You have written the comment that most made my day, "I can say that your bike may work as you say, but not for the reasons you mentionned".

If that is true, I am the single, luckiest person on the planet.I have manged to design a complicated mechanical device that does exactly as I predicted, for all the wrong reasons. It might not quite be the apple falling on Newton's head, but I'll take it.

If you apply the classic rules of anti-squat, you are correct, if there is enough chain tension to lift the bike, there is loads (technical term) of kickback. Does mine have some? Like every non-concentric pivot bike, yes it does. Like probably every full suspension bike you've ever ridden. How much is too much? When you feel it, when it hampers your cadence. In this case, it does not. Certainly not where any tester has noticed, even when specifically asked to look for it. Just for fun, take your shock off and compress the suspension and watch the pedal feedback.

So, maybe I'm not doing it with excess AS. Maybe the force inputs from the Missing Link ARE responsible, and do not require excess chain growth to accomplish. Maybe that's why I can do the things I claim.

Physics are our friends, It is fun to hurt them back, when given the chance, since they've caused me enough pain over the years. But while we're on the subject, throw down a few free body diagrams for a real idea. Physics 101. Don't they teach that anymore?
  • - 4
flag faul (Jun 30, 2016 at 12:32) (Below Threshold)
 @tantrumcycles:
I don't know if you didn't explain what you actually did, if I don't understood correctly (I don't speak english really well), or if you're lucky, but what you said in your videos and wrote to several people can't explain why your bike work.
I won't say there is too much kickback, as it would require a full analysis of the dynamic of the bike, and results will vary for each crank arm/shock/ chainring size... I was just giving an exemple of your bike acting like any other out there, compromises are the same. And no, not every bike has kickback. some exemples of bikes that doesn't have kickback: a single pivot bike with the pivot lower than the chainline, URTs, idler pulley bike with the pivot or IC lower than the chainline...
Force input from the missing ling have obviously an effect on the suspension, but so have the force imput from the seatstays, and same with all the parts. Thats why I mentionned axle path, IC curves, and other things, they summarize all the effects so you don't need to know what happens in each part anymore (to study the 2D suspension, you'll need that everywhere else)
Actually your missing link does give the axle path a great rearward motion, that axle path gives chain growth, kickback, anti squat, pedal bob (but upside down, as you lift the bike), and many other things. If you didn't take into account the other parts, you are actually lucky because at the beginning of the travel it has a preponderant role in the axle path.

I won't draw a free body diagram (I just learnt the english term so thank you), as I already know what I will learn: quite nothing. but put some parameters on them, "solve" the equations that link these parameters, and you can sart to fill the matrix of the bike, that will show you everything at every moment of the suspension action.
  • + 19
 Mr. Berthold is not only a master of suspension design but also a master of sarcasm calling a bike with 14 bearings and 3 links "missing Link"...
  • + 16
 I love a clever engineering design. All I have seen is people trashing the shape, design, number of moving parts, graphics, colour, etc, etc.... A smart man has come up with an awesomely clever design. Awesome. Good luck with the future. And don't listen to all the matte black sheep. I love colour and clever design.
  • + 10
 I had a conversation with the designer/inventor over on MTBR, super nice guy and was pretty quick to answer questions. Glad to see a good review on his bike! I appreciate some out of the box thinking to close some legitimate performance gaps.
  • + 9
 Very cool looking and original bike. I'd totally wear rasta pants to ride it. However I must say RC that if there is something that pedals better than my current bike with CCDBCoil and Climb Switch, then it must be a hardtail... even with climb switch off I can feed quite big chunks of earth's crust through turned up LSC on that bike. Nevertheless, sorry for drifting away from the topic, this Tantrum looks extremely interesting, a fresh breath into "established air" in the industry, and I'd love to have a go on it. Love the engineering, love the graphics.
  • + 1
 Dig it! I thought the magic link was rather rough cut when it debuted. But this execution of the same concept is far more refined and if it could be sold, or at least licensed to a proper boutique brand it could be cleaned up and may actually be a revelation.

I really hate to be the one serving the coolaid but imagine how fast true beginners could progress if there was a +size in this for Ones who really need the characteristics this offers.

Nice wife who doesn't ride would really enjoy the benefits of this on the off occasion she tries to ride
  • + 9
 Bold statement from RC. This bike is on to something and I will be very interested to see what direction this heads.

It needs better graphics and RS or Fox suspension with fast black/Kashima and a dropper post if it is going to sell, though. The graphics do not compliment the aesthetics of the frame.....it really clashes and with the price of bikes...you're damn right looks are important. We have to ride these things for 5-10 years before we pawn enough heirlooms to buy another one.

This is set up for an ugly-duckling story. Make it happen!
  • + 6
 Problem is there isn't a damn thing wrong with X-Fusion products and you can get an amazing fork at half the price of the big 2. Would also help keep the overall price of the bike down which would actually help it sell faster. People customize their rides 9/10 times anyways so I'd rather buy a bike with xfusion for 3grand than a bike with fox for 5
  • + 1
 @Mtbguy87: x-fusion makes good stuff, no doubt. But the stachion coating is associated with "cheap". Maybe not to you....but to the market.

You think the fox dropper needs to be Kashima coated? Of course not, but if you're willing to spend a little bit extra, you get the bling.

Works in every industry, and it IS a deal breaker whether the smart consumer thinks so or not. Solid product that looks good....I'd rather have that then a solid product that looks "cheap"

I personally have no issue with Manitou or Xfusion or BOS. But stack anyone of them against a factory fox to the masses, and they will buy the fox.

Also, buying the cheaper option with the intent to upgrade is more expensive. You've bought a oem product (fork for $500 built into bike price) that you can't sell with a gauruntee or warranty so you sell it for less than its oem price especially if it's used ($350), then you pay the oem price for an upgrade vs it's oem price ($900 vs $700). So instead of spending $700 for the upgraded fork you originally wanted, your spending $1050 for the upgrade. On the flipside, you can make money if you're super smart and your buyer is super retarded.

IF you can afford what you want in a package....consider the savings.

BTW purchasing power goes a long way in savings which is why Jensen and CR can offer such huge savings.
  • + 1
 Maybe one day when x fusion makes a well damped shock
  • + 2
 @kleinblake: They already do. And the Metric HLR ist the best fork i have ridden up to now.
  • + 3
 @ghettoflash: If you read the story you'd know they are only selling frames, so you won't be paying for a low end fork only to replace it.
  • + 1
 @Fresh1: ahhhh! Good call. I missed that.
  • + 2
 @ghettoflash: the problem is if a consumer strictly goes off looks than that consumer is a retard. I wouldn't take a bling fork over performance. If I know I can get an equally performing product for couple hundred or even thousand dollars cheaper than that's what I do. All these new guys want their stuff to look pretty but I'd take performance over looks any day of the week. riding isn't a beauty pageant it's about feeling comfortable on a bike of your choosing. I've never had any issues running xfusion and manitou products and prefer my dorado over a 40 or boxxer. Does having kashima or fast black make you a better rider? Absolutely not.
  • + 2
 @Mtbguy87: oh don't get me wrong. I totally agree. I'm just a study of the market. The average consumer has different priorities than the specialized one.

In a head to head. All things being equal, the better looking product will be preferred.
  • + 9
 If the industry would stop with all the constant axle spacing/shock sizing/tire width standard changing nonsense we would probably see a lot more innovation like this. As it stands, everyone is constantly chasing standards and trying to one up each other at the expense of true innovation.
  • + 8
 My take... It would be pretty rad to build that thing up with a simple, super active shock that's made all for downhill like the one from stantec/extreme and have super plush suspension, yet super good climbing. And I'm even digging the color and graphics! Never change those!! Retro for the win ????????????????
  • + 2
 Or a nitro shox
  • + 8
 Cut the guy some slack- this is the first new suspension design in quite a while. The graphics will come around, as have a lot of style attributes of yesteryear. As for the number of pivots- lots of companies are using 4-link suspension or single pivots with motolinks (e.g. Canyon Sender, Scott Gambler ) - this is much more of a benefit. Most of the pivots are inside the front triangle and above the bb... out of harm's and dirt's way.
AND I do like the idea that this might help keep electronics where it belongs- in the office rather than on my bike.
  • + 10
 Who cares how it rides, it's all about out-bro'ing my bros in the trailhead parking lot. I'll stick to the cool brands.
  • + 4
 I assume there was a big ol serving of sarcasm dished up with your comment.
  • + 9
 Interestingly, there's no dropper post on this 160mm bike. Did you ever feel like it was missing while descending?
  • + 35
 Funny story. Brian didn't have any droppers on hand when he built the frames up, and I forgot to bring mine, so we had to old-school the downs, stopping at the top to lower our posts like the early freeride days. Been a while since Ive done that! RC
  • + 5
 @RichardCunningham: lol, thanks for the quick reply!
  • + 7
 @RichardCunningham: As I can't really afford a DP right now, because saving for another fork, stop and drop is what I've had to do for years.

After I get another fork for this other frame(Hornet), I'll be looking at Gravity Dropper. Though, for the sake of being a 40 year old MTB'er I'm patiently waiting for the release of the Orbea Digit Dropper just to check it out.

Digit Dropper would be the one extra part I'd like in my truck just in case my primary dropper goes south. Though, I don't expect maintenance issues with the Gravity Dropper.

Okay, sorry for going off topic. Keep on throwing down the awesome articles, and keep shredding!
  • + 7
 @RichardCunningham: after about 25 years riding I broke down and got my first dropper this season, after just a month can't image riding w/o one - wait, I can when i'm on my hardtail (26.8mm seatpost) and it sucks not having it!
  • + 5
 @Grmasterd: I'm sure, deep down in his parts bin, @RichardCunningham has a HiteRite you could borrow for that frame.
  • - 6
flag Mtbguy87 (Jun 27, 2016 at 19:02) (Below Threshold)
 It's at the point of dropper posts that I lost faith in mountain bikers. I'll take a QR and a Thompson any day over a DP lol
  • + 9
 @Mtbguy87: when the trail points down, kindly pull over because I will be going waaaaayyyy faster than you.
  • + 2
 @Mtbguy87:
Get real bud.
You must live where it's flat. Or have no clue what's going on out there.
  • + 3
 @jflb: I didn't know the pnw is flat. Also didn't realize having a dropper post means you live in a mountainous area Smile but what do I know i grew up in the flat Rocky Mountains as a young man lol
  • + 0
 @rglasser: well you better try to maintain speed. Majority of you endurbro riders are slower than a snails ass on the downward slope.
  • + 5
 Just curious, @RichardCunningham - did you happen to try it on any jumps? Particularly where you landed with the back wheel first? I'm curious if that'd keep the suspension locked up. (i.e. not provide the rearward force to activate the scissor linkage)
  • + 3
 Landing jumps felt pretty normal, I didn't do much back-siding because most of the jumps there are rock drops or natural outcrops where I was landing pretty level.
  • + 2
 Hi Gsnake. The suspension won't have any tendancy at all to be locked when landing from a jump. Because there is no pedaling effort to overcome resistance to forward motion. Without a significant pedaling effort, there is no possible way the suspension can even resist your body weight, which of course, is the only reason it will sag when seated, just like a normal bike.

The rearward force to activate the scissor action is only necessary when climbing or pedaling hard. Because that is when the "stiffening" effect is in action. If you are coasting, you will get an extra degree of compliance from this action, but the shock would never be at full extension with the pedaling biasing force.

Does that make sense?
  • + 6
 So where is the data? I want to see leverage ratio curves, anti-squat curves, etc. Show me how this is better, don't just tell me it does what no other suspension could do until now.
  • + 5
 Interesting design. It's surprising the designer didn't splurge on a top end name-brand build kit to make the frames look their best for the review. Instead, it looks like 'here's a frame you could hang those oddball parts you have lying around on.' Perception is important- CB is still around!
  • + 4
 I rode a transfer stage at an enduro race with Richard. Really nice guy and the bike is quite attractive in person. I guess I wasn't focused on the linkage because I had no idea who he was or anything about the bike except that it was his design. The frame tubing has some nice shaping and the bike had a very aggressive look to it.
  • + 1
 hey Jeremy, was that me, brian, at Sea Otter? Hope I didn't get in your way.
  • + 1
 @tantrumcycles:
Yo Brian. Yeah, sorry for the poor literacy. Don't know how I confused Richard. Good chatting at the otter. Best of luck and really nice looking bike! Hope I get to try one someday.
  • + 6
 Send this frame to Devinci's industrial design team and you'll have a gorgeous bike, their work on the current Spartan and Troy (more so) are works of art.
  • + 4
 I remember everyone talking about how lame the original Outland bike looked when it first came out in the early 90's. Apply some marketing magic and good industrial design and you now have Santa Cruz bikes VPP design. If it really does work as well as RC says with crappy low level X Fusion suspension imagine it with some real suspension and with nice carbon lines. What he really needs is someone with cash and marketing experience.
  • + 5
 Those Magic Link Konas actually ride really well, but got squeaky as hell. Less moving parts here, so shouldn't be an issue! I really appreciate these innovating types in the industry. Good job!
  • + 4
 Now this is new technology that is exciting! So much more interesting to read about than electronic suspension or e-bikes. I Really hope this works out. Maybe a big bike manufacturer will license the suspension so he can get rewarded for his invention and we can get a nice polished design...
  • + 4
 The other day pb did a poll of how can the trail bike advance. Well this is a step in that direction. A fresh approach on things. Sometimes i think frame manufacturers are so tied in with suspension manufacturers that they almost design frames around the performance qualities of the suspension. They have massive contracts with the suspension manufacturers that they kind of have to showcase their shocks. And we all know that the major suspension manufacturers are some of the biggest and influential, particularly when offering OEM packages to frame manufacturers. Glad he has a patent on it. Sure its early days and this can, in a way, be looked on as a prototype of soughts, but its exciting to see the mtb trail bike being approached from a different direction.
  • + 5
 I think the guy's a genius! It is essentially a simple design that actually works beautifully. Which often is the best. If it were a bit more polished round the edges you'll see everyone on the bandwagon soon.
  • + 7
 Coming soon, a ladies version . The Hissy Fit.
  • + 1
 There's already a waiting list. Starting with this lovely lady: www.pinkbike.com/video/159119
  • + 4
 I like this guy, I like his attitude, his ideas, his philosophy and I definitely like his suspension designs. Like it was said earlier, beef up the componentry and you'll have a trail tank. Don't hate, innovate!
  • + 2
 Sorry @RichardCunningham but this part bugged me a bit:

"'...pedal like a cross-country bike and descend like a DH bike.' (I’ve written that phrase more times than I should have)”

I know a guy that refuses to read MBA and other bike reviews because he swears they’re all puff pieces for bike companies. I’ve always presumed that you’re giving us the 100% low-down on a bike. Did that sentence mean that you’ve written that about bikes that didn’t really climb/descend as stated?
  • + 0
 No. It means (like so many in this biz) that I have used that cliche far too many times.
  • + 1
 @RichardCunningham: Thanks for the response! You of course get my benefit of the doubt. The sentence just perked my eyebrow a bit.
  • + 3
 I am 100% digging this bike. Everything from the graphics to the skin wall tires. I am a sucker for gimmicks and this gimmick seems like a great idea. I don't know if it would replace my VPP, but I'd give her a rip!
  • + 2
 In case any one missed the news. The campain is finnaly live at www.kickstarter.com/projects/812273700/tantrum-cycles-the-missing-link-in-full-suspension

Imoh a good read even for the less open-minded, sceptics and haters around ;-)

I'm proud to have sign up for production frame NR:1 !!! :-)
  • + 1
 and thank you sir for being the FIRST!!!! woohoo. That's our first sale as Tantrum Cycles, balloons are being released as we speak. Your frame will be specially annotated as the first ever. thanks again, cheers, brian
  • + 2
 Would equip with Mattoc, and for shitz and giggles a 2016 DPS Factory or Monarch RT3. It would actually be awesome to see different shocks set up on this frame, with details to each shocks performance. I'm thinking that to many shock adjustment features might not be for this frame as the rear linkage is supposed to be doing what the control features of many rear shocks have been designed to mitigate. And, I could also be wrong. Looking forward to more info during production. I look forward to seeing your whip on the trails Mr. Berthold.
  • + 2
 Amazing! I can't remember any PB article or other bike tech article causing so many and great variety of clever and stupid comments? :-)
I suspect the Missing link patent is an invention that will become an milestone in bike suspension history. But since so many seems to be more concerned about how bikes looks then how they ride, I guess it might take som time.
Keep up the good work Brian! It world be so cool if Tantrum could grow to become a reputable brand by its own, and let the sceptics keep on tinkering with there platforms, switches and compromising sag-settings..
  • + 3
 Thanks for the brake from the yuppy larva fanny packs and press fit carbon suppositories RC - this is an article that actually didn't compromise my heart health. Keep'em coming!
  • + 4
 If this was Yeti, and the bikes had carbon frames and smooth looking lines, the industry would be going wild over these bikes
  • + 2
 As far as I'm in awe seeing what this man achieved alone, I cannot help but wonder:
Is it necessary? I mean, the climbing and decent performances of this cinematic sound otherworldly, but nothing is perfect and with shit-loads of links and an odd attach point for the shock come maintenance and weight ( mtbers are weight weenies at heart),and maybe others. My point is, today we have voodoo technology in shocks that allow us to radically transform how a bike climbs. Is it more clever to have a simpler design( vpp, 4bar...) and a lockout/climb-mode or a magic link? I can't help but smile when I read "Omg, that's uber-cool, I don't need to switch to climb mode to go up.", well, my 2009 remedy isn't that much of a climber at heart, but turning a flick makes it very easy to ride it uphill... while having 35+%sag for the downhill.

I don't want to sound negative, I am just rightfully wondering. And props to Brian for achieving this, an evolution is always welcome and doing it all by himself is impressive at least!
  • - 2
 i too prefer a switch on the shock to using the linkage for pedaling firmness
  • + 2
 @polarproton -> agreed. I like it but how does it measure up against active designs with voodoo mojo like Trek's re:aktiv damper, the mentioned magic Fox electronic valve thingie and the like. Did RC just inadvertently imply the design is mute due to super shock technology progress? Be that as it may I like the design and wouldn't hesitate to swing a leg over one. Nice to see some people are still thinking.
  • + 2
 The preference to use a high performance shock is fair, and typically, doing that will benefit suspension performance in a range of riding contexts, not just climbing. But, I think Brian Berthold's claims for the Missing Link go beyond achieving ride related adjustments to the feel of the bike. He further claims that there is a more or less automatic change to the geometry of the bike in high torque pedalling sitiations where due to certain characteristics of the linkage the bicycle chassis rises up on the suspension increasing ride height and sharpening seat tube and steering angles. Having a climbing mode on hand that includes geometry adjust in addition to firming up of the shock during high exertion pedalling is a more complete response to the demands of climbing than making shock adjustments alone. I believe, the closest analogous geometry adjust behaviour to that claimed for the Missing Link is achieved by Canyon's Shapeshifter, with the significant contrast being that to enter 'climbing mode' on the Tantrum bikes requires no deliberate invocation, i.e. no flipping of a lever, by the rider. The rider just rides and the linkage automatically makes geometry adjustments based on the way that torques are managed by the Missing Link design. The specific behaviour of the Missing Link bikes in various riding situations needs to be more fully documented but if everything works as described and there are no gotchas it would be quite unique in the ways I have outlined.
  • + 0
 @stillunimpressed: If the two links that connect at the shock could rotate such that the pivots were actually lined up or even past lined up, so that the shock mount moves toward the seattube more, this would actually function as Berthold claims. However, given that those three pivots don't actually move past a straight line, Vrock's assesment is correct: it's just an extremely low leverage ratio and high anti squat at 0% sag that sharply declines through travel.

The real bullshit is when Berthold demonstrates the function in his videos with the shock unattached, which allows the two shock-driving link to rotate more than they would otherwise. Then, it's noted that when the shock is attached the links don't actually hit the seattube.
  • + 3
 @b26-4-Life: Those pivots do not need to be in a straight line to have the effects I am describing. In fact, if they were, the response WOULD be more similar to what vrock has described. But, in fact, it behaves as I have described and as is shown in our videos.

The actual degree of rotation of the links in the video is not really relevant to what I was trying to show. Obviously, neither was the contact from having the link over-rotate. the demonstration was merely to show the direction of the horizontal forces as they are fed into the linkage. Those forces are real, as demonstrated and they affect the linkage as I am showing in the video. Once the linkage is re-assembled, the forces still act the same and affect the linkage as a whole.
  • - 1
 @tantrumcycles: All you have to do is publish your LR and AS curves and then we can see.
  • - 1
 @b26-4-Life: You have got me wrong. If you examine my comments below you will see that I agree with you as to the inadequacies of Mr. Berthold's explanations of how the suspension functions on the Missing Link bikes. If I'm not mistaken, I was the first person on this page to mention Vrock's analysis. In fact, I provided the link to it and I subscribe to the views expressed there. All I have said here is that, a degree of geometry adjust, sharpening seattube and steering angles, gained by natural pedalling action, a behaviour that has been documented by Mr. Berthold (in a video record of suspension extension) does make the performance of the Missing Link suspension rather unique. I am not trying to dissuade you from a preference to flip a climb switch. What I have said is ride adjust and geometry adjust are not the same and that on available evidence the Missing Link bikes appear to offer some degree of both. That I am happy to acknowledge the unique characteristics of the Missing Link does not mean I subscribe to Mr. Berthold's specific statements about how that unique behaviour is achieved.
  • + 0
 @stillunimpressed: We're on the same page here; i was posting in support of a traditional analysis, unrelated to my personal preference for neutral AS linkages. I agree that the linkage does what Mr. Berthold suggests to some degree, but through the mechanisms of AS and LR as discussed by yourself and Vrock.

My point is that in his marketing material, Berthold suggests that once in it's "locked out" position, the linkage will stay that way until acted on by bump forces (he specifically attempts to illustrate this in the video with the shock unattached), but I disagree. If there was some mechanical way for the linkage to go past top out so that it was actually pulling on the shock and stuck either against the seattube or stuck by trying to pull the shock past top-out until a bump force shifts the lower link (as he specifically demonstrates with shock unattached), i could imagine the possibility of what he is suggesting, but because of the clearly shown alignment (with the shock atttached) of the shock-driving links ensuroing that vertical wheel travel always moves the shock mount forward, and the fact that the bike always sags into travel without chain tension, it's obvious that any "lock-out" effect is momentary, very dynamic, and driven by high AS, and as pointed out by Vrock, aided by the falling rate LR. We are in total agreement, i was just using a more visual way to look at it.
  • + 0
 @b26-4-Life: hmmmm, but it really happens. You can disagree, but how do you explain that?
  • + 0
 @tantrumcycles: Look, i'm not going to argue this any more, but in a rational discussion, you can't say this:

"If you pedaling effort is reduced the sag will gradually and proportionally increase. As you reach the top of the climb, the sag will return to static level even as you keep pedaling to finish the climb." (as you do below in this discussion)

and then disagree when I say this:

"Berthold suggests that once in it's "locked out" position, the linkage will stay that way until acted on by bump forces (he specifically attempts to illustrate this in the video with the shock unattached), but I disagree...the fact that the bike always sags into travel without chain tension, it's obvious that any "lock-out" effect is momentary, very dynamic, and driven by high AS"

Whether it's right or wrong, you have to pick one of them to argue.
  • + 1
 @b26-4-Life: The suspension is only "locked out" when there is sufficient pedaling force, i.e. a steep climb, to induce this condition. It is while in this condition that the "knee effect" occurs.

So, while you say the "lockout effect" is momentary (as, indeed, it would very much be if only the product of AS), it is in fact, very consistent throuought a climb, as my videos clearly show. A high AS suspension cannot demonstrate this behaviour. It will relax into the travel at the dead spot in the crank stroke and inchworm its way up the climb. If you've ever ridden a C'dale super v, super 8, bullit or the like, you will know exactly what mean. Along with the real definition of pedal kickback. Those are all very high AS bikes. Bad. Gone. Good.

Again, the lockout only occurs at high pedaling effort due to climbing. It will stay that way until you hit a bump or cease climbing.
  • + 0
 @tantrumcycles: b26-4-Life is not alone in finding your account of the "lockout effect" unsatisfactory. That does not mean that there has been an outright rejection of the possibility that your suspension design may have been able to achieve an extensive effect that is "consistent throughout a climb". That is something that many us would like to understand better. But, there is no need to rush to explanations that appear tenuous. I, for one, would have imagined that the Outburst and Meltdown suspensions would have bobbed while climbing. That this doesn't appear to happen is, for me, a source of fascination. That is also why I called for a more complete account of the specific behaviour of the Missing Link bikes in various riding situations. If the extensive effect only occurs while climbing and never gives rise to suspension bob, whether climbing or in other riding situations, that would be impressive (although, in line with my other comments, I reserve judgement on whether that extensive characteristic is an exemplary design objective).

The suspension behaviours that we are discussing are sufficiently interesting and important that they rightly command our attention despite the lack of agreement over how the effects are produced.
  • + 5
 Anyone else think, looking at the geo chart, that it's a generation behind on current reach and HA standards
  • + 4
 Head angle with its 66° seems ok I think, but 73° seat tube angle seems pretty low. Alo reach makes me really cringe. 399mm for size M? Wonder what the seat tube lengths will be, 399mm reach would be more suitable to a size S, and even there I'd consider this an outdated value nowadays.
  • + 3
 @sp00n82: The bike looks great, but that reach seems really short
  • + 3
 Sorry, forgot to mention, new geo chart for production bikes soon, longer reach/shorter CS/27.5+/boost rear OPTION, yadayadayada. Seriously. And final frame sizing choices still being sorted, how many of each, etc.

Hey, my first one was, gasp, 26" wheels and 135 mm rear end. What was I thinking?? Fun bike, though.

The website, etc, will all be updated soon. With production graphics, don't even ask, I haven't seen any concepts, yet.
  • + 1
 @tantrumcycles: good to hear! Looks like a great bike - whats the pricing in the UK going to be?
  • + 0
 @sp00n82: Indeed, there some issues with geo. But, I think the somewhat slack seat tube angle (judged by today's standards) must be looked at in light of the claimed performance characteristics of the linkage. Brian Berthold, the designer of the bikes and the "Missing Link" linkage, maintains that the rear suspension extends during high torque pedalling (i.e. uphill mainly) and that there is a sharpening of seat tube and steering angles of at least a few degrees in that situation. If that is true, and the claim is backed up by video evidence on the Tantrum bike site and by RC's statements in the article, then the slack seat tube angle wouldn't amount to much in practice. I have many questions about this linkage but, considering the information that has been presented, I am not greatly concerned about this aspect of the geo.
  • + 1
 @WAKIdesigns: I rode this bike yesterday with Brian and rode it along the lines of dirt bike. Throw it into corners, try and maintain corner speed and squirting out. This bike rails corners and then when it comes to stamping on the pedals on the exits, I didn’t feel the usual softened bob on back end of the bike on every downward pedal stroke. On the straighter, more level sections, I would speed up and literally feel the rear suspension firm up. It was like there was a hidden pump somewhere, which sensed when you pushed down on the pedals and would add some air to the shock and it would extend! The same was true when it came to climbing, the rear end would harden up, the shock would extend and you could feel the bike go forward and not bob and go forward. The bike has a neutral feeling, it rails corners with confidence and did not feeling top heavy. Also it wouldn’t get out of shape when hitting roots in corners at speed. Normally I would expect a bike to feel “skittery” in situations like that, but this bike felt planted, both front and rear. This one of the best f*cking bikes I have ever ridden. It’s in the “one bike for pretty much does everything” category.
  • + 1
 Demo rides near Boston area in mid august. If anyone is interested, please drop me a line from our website, www.tantrumcycles.com

The bikes are med/small and there are limited spots, so let me know if you're interested. We'll have the 160 x 27.5 Meltdown and the 125 x 29er Outburst.
  • + 4
 I enjoyed my magic link bike, but those graphics might as well be comic sans.
  • + 1
 Hey Richard...in order to get your heavy duty fans believe in the promising Missing Link there's a thing only you can do: grab one of each type of frame, dress them up to you're own preferences...till you can say us they are your dream bike...as in your Intense Tracer days...definitive for all your fans. You're great man. You rule !!!! Cheers from Valencia, Spain!!
  • + 2
 Would be nice to try one out. If its affordable wouldn't mind snatching a frame myself. Also paint job would've been better just all matte black with white letters or something of that sort hahaha.
  • + 1
 Wonder what the spring curve is like . The only thing that I thought the old magic link fell down ride wise on was being to linear for jumping. I did try altering the volume on the main shock but it messed the very fine balance of the magic link right up so that wasn't a option. And if he wants some UK testing sign me up
  • + 1
 i.imgur.com/iZKJ2sP.jpg --That's Antonio Osuna's guess at it, based off a picture.
  • + 5
 I guess I look like an idiot with my answer on yesterday's poll.
  • + 1
 I thought we were past looking for 100% pedaling performance in long travel trail bikes and we are happy with good pedalling (which most bike offer) as long as the suspension offers amazing performance on the downhills? Or is it 2003?
  • + 3
 why not strive for the best of both worlds and have amazing uphill and downhill performance. this new design may or may not be the answer but its great to see something new and killing innovation on the basis that what we have is alright just seems stupid to me.
  • + 3
 Somebody else mentioned it, but if this means a 175mm rear travel bike can pedal like today's 6" bikes with no further changes, then it's a significant advancement towards actually performing like a super dialed park bike, but be usable as an everyday driver.
To me, the mid travel 29er is attractive, since getting a bit more pedaling efficiency is always nice on a bike that can keep it so well, with more capability in the bank for rugged all mountain use.
  • + 1
 I don't care how well it rides if it means more maintenance. I also don't care if my mini-DH bike has 5% bob on the way up instead of 0% like a hardtail. It's not worth all the other trade offs.

Kudos for pushing the envelope though.
  • + 2
 I like the idea of frames doing more work, rather than getting crazy e-shocks on my bike. Also, my X-Fusion shock works really well.. 4 position switch instead of 3 position is actually pretty rad.
  • + 1
 "Each time I showed the Missing Link, the response was the same," said Berthold: "It works great, but bikes are pretty darn good right now and we don't want to allocate the time and expense to develop a new suspension."

I have zero understanding of suspension design, but that sounds odd. Yeti recently spent time and $$ on two unique suspension designs. Specialized and Santa Cruz built premium brands around patented suspensions; patents that just expired. Now competitors are selling those same suspensions for less. I imagine Specialized and SC are desperate to find a new market differentiator and would love to license a superior new suspension. They must have a reason for passing on Berthold's design.
  • + 2
 All of those companies have huge investments in the molds, marketing and looks. They're selling tons of bikes and have their model year pipeline invested years in advance. Not to mention a little belt tightening, industry wise. I don't blame them. Some of these people are my friends who would love to do it and have no budget. And maybe some companies, I have yet to decide to approach, for various reasons. are some afraid of this? Of course, as many of you are. I don't blame them for this either. For various reasons. I'm not asking for a free pass. I'm putting my money where my mouth is. I'm forcing the issue. Timing is everything, so it's time for me to get this out there so people can ride it.
  • + 1
 @tantrumcycles: Id love to try one, I cant afford one at this moment but what is the suggested msrp gonna go for? And is there any type of warranty? BTW, great job! HArd work pays off and I wish you much success!
  • + 1
 @tantrumcycles: Extremely true over everything, especially with lots of brands having been caught out by one standard or another in just the last few years (27.5, 148x12/110x15 boost, 1x drivetrains, long reach/shirt chainstay geometry, 27+, 29+, etc.).
Add on the costs for molds, development time and costs (why Specialized and Santa Cruz still have an edge working with Horst/VPP designs), and the fact that certain markets have hour early saturation points (primarily because most every bike rolling onto an LBS doesn't suck our break prematurely) and it's hard to make a risk justification to invest huge money into something new and different if status quo is still profitable.
  • + 1
 @tehllama: Maybe Specialized and SC are content with what they have, I don't know. But Canyon seems to be interested in new suspension tech. Lapierre has been developing electronic suspension controls. Cannondale redid their suspension recently. Yeti did too, twice. So some companies think this is a good area to invest R&D $$.
  • + 1
 @barcolounger: The answers in the two cases you listed have been shapeshifter, and E:I respectively, which are non-kinematic workarounds for solving the same problem.
Cannondale are mostly closing of the Dyad pull shock add a technological oxbow, and moving back to conventional suspension and linkage driven single pivots. Yeti figured out how to make a translating pivot not work poorly, though in my experience it's very much a dual-link type experience with really high anti-squat that blows off into mid travel and feels critical regarding chain tension and LSC tune.
To answer your question, the only one of those trying something unproven already had switch infinity prototypes, and it's easy to recoup R&D costs when selling $3400 frames promoted by a top notch EWS effort.
  • + 4
 I also want to mention that I am still having conversations with various companies and there are certainly many more that I have not even had the chance to contact. I would love to spread it around, yes, of course to make money, but my real goal is to get people on the bike, to enjoy what I've come up with. So I didn't want to wait. I want people to be able to ride my bike now. So Tantrum Cycles was born.
  • + 0
 Using VPP as an example is maybe a little bit of a stretch, as (until the latest generation, which are good) it was inferior to most designs for a lot of reasons, but I totally agree with your general idea.
  • + 1
 Anyone got som thoughts about the DVD Topaz upgrade?
As this linkage is made to work as intended without complicated and expensive propedal and I would guess a advanced piggyback shock might be overkill for me q since I also have 25% to face and also intend to cash out for 1x12 drivetrain, good brakes and decent wheels.
  • + 1
 (as in.. 25% VAT! )
  • + 1
 I'm convinced with some time someone could design that linkage system to look a lot better. It's not ugly it's just not all the nice to look at. To be able to eliminate lockout cables or not having to reach down to clit play a switch seems pretty good to me, I'd be more than willing to try one of these out.
  • + 6
 I can't see the link when i'm riding the bike... and what's that about clit play?
  • + 4
 @scottzg: I can't see a lot of things when riding... some times those things are trees....

As for clit play... you heard me lol
  • + 1
 I count seven pivot points on one side. That is a great deal of bearings/bushings to deal with. No matter how awesome the bike may be, those pivots will require maintenance. I applaud Mr Berthold's imagination, however adding complexity to such efforts historically has not paid off (see Cannondale Gemini, etc.). In contrast, Dave Weagle's DELTA system is ridiculously simple and has received rave reviews.
  • + 1
 The idea here is actually not so far from the dog-links of future past GTs and Felts, prone to breakage in both designs. Critical in this execution will be the transition from "locked pedalling" to major a big hit compression. The frame and bearings has to tolerate a major load and have an easy transition into rotation of the links and compression of the shock. Pivot placement and angle of the driving link is key
  • + 3
 An enduro bike with dynamic, mechanical lockout that has plenty of room for a water bottle. I want one.
  • + 0
 Missing link ?? Yup that would be aesthetics. it is a great design theory, machine work, welds, etc, just not a fan of the look. However there have been some fugly bikes over the last 25 or so years that have been less than attractive and have done well in sales and cult followings, so...
  • + 1
 Crazy stuff going on there, reminds me of when I first saw the old Demo and was trying to figure out wtf was going on with all those links. Anyway, cool engineering, cool gumwalls. Respect.
  • + 0
 The linkage is distantly related to the Felt Equilink and like that linkage it is a 6 bar Stephenson I link, I believe. I don't think there is any special significance that follows from the biasing link - Equilink on the Felt bikes and the short link sitting behind and just above the more elevated rearward mount of the shock on this bike - attaching to forward projecting sections of the lower and upper short links in the manner of a rocker. That is just one of many ways to govern the relative motion of the lower and upper short links using a third link that determines the bias/relative rate of rotation of the two mainframe mounted links thus connected.

I looked at the video explaining this linkage - see
www.youtube.com/watch?v=uh44UMTOmB0&feature=youtu.be
That is a weird experience. Brian, the guy doing the talking, disconnects linkage pivots in order to explain how the linkage works. But, that is an entirely invalid move, because the linkage can only work at all as a connected whole, that moves as one system, not as a series of free parts.

Also, a claim is made that chain tension from pedalling can hold the linkage in a position that keeps the rear suspension in a fully extended state. First, that claim doesn't amount to much because for a bike with a properly adjusted SAG, there is no amount of chain tension (that can be generated by a rider) that can somehow lift the bike up and hold it there when its natural tendency on the contrary will be to return to SAG. Second, in the only imaginable circumstance where chain tension might produce the said effect - after the suspension fully extends due to a dip or leaving the ground - if chain tension holds the linkage and suspension in a fully extended state, that would be a very bad thing. Chain tension would be overriding the normal and correct behaviour of the suspension to return to SAG according to its natural and correct function with a ill considered operational scenario of holding the bike in an extended state for no reason. As the claim is very probably untrue, in any case, perhaps, there is little reason to worry about this. Finally, not just the claim about the effects of chain tension but everything that Brian says is dubious. He talks about a lot of forces that don't exist and fails to talk about the one that does - anti-squat. A normal analysis of this linkage and bike provided by the Linkage program or something similar will give the true picture of how this bike acts when pedalled.
  • + 2
 Never owned a bike with a magic link have you. Because guess what chain tension does have a effect on the linkage quite easily. If I set my magic link up soft or if I'm really cranking hard you can see the magic link shock unloading and moving to fully extended if you look down. And yes it does work great. I can be smashing a dh with all the super smooth squidge I want then put in some pedal strokes between corners and get actual acceleration like no other as the suspension is firmer under pedal power. The man knows his stuff.
  • + 6
 I think you missed a few things - especially about how the system uses chain tension to actuate the linkage. Give it another look.
  • - 2
 @markg1150: There is no shared nature between the Magic Link and the Missing Link. I am sure Brian Berthold would tell you that himself if he became aware that the two were being conflated. This linkage is a 6 bar linkage in which the motion of the linkage is determined by the particular connection between the bars making up the linkage alone - the linkage tracks the same path every time the suspension is compressed. The Kona Magic Link, however, was a 5 bar linkage in which unplanned or irregular motion of the linkage could not be ruled out on mechanical grounds. The claim of Berthold was to turn this apparent disadvantage to an advantage by pre-loading one of the links with a one way force - that is what that little spring in the linkage does - that acts to overcome uncontrolled linkage motion and to render overall linkage motion in action more regular and predictable (although not exactly predetermined i.e. where motion of the linkage doesn't admit any variation relative to the degree of suspension compression) when met by other forces such as chain tension and shock compression force. These forces were opposed in interesting ways to achieve the very unusual action of the Magic Link. I did not say and don't say that the Magic Link didn't work as advertised (although it would have required attention to keep it working that way). But this linkage doesn't work like that! The only things that can cause a change in the relative positions and orientations of the links besides bumps and dips (i.e. trail input) are acceleration and deceleration. There is no equivalent to the Magic Link that despite its connection to the other linkage bars, due to its partial mechanical freedom from them, can be shunted about (in a controlled fashion) by careful use of external interference or application of pressure on that bar.
  • - 3
 @RichardCunningham: as my response to @markg1150 should make clear there are good reasons for not accepting that chain tension can achieve that effect in this case. I am not saying there is anything wrong with the Missing Link, only that it needs a conventional analysis like any (true) six bar, because that is exactly what it is.
  • - 2
 @RichardCunningham: That conventional analysis I suggested is required has already happened apparently - see Vrocks entry at forums.mtbr.com/all-mountain/new-inovative-suspension-tantrum-cycles-any-thoughts-1009862-2.html

He says,
"At the end of the day this bike follows the sames principles as any other bike. It's a Virtual Pivot with a "Spike" of Anti-squat at the beginning of the travel 180% at 0% and 120% around 25%. The Leverage Ratio has another "Spike" at the beginning of the travel where it goes really low (1.6), but around 25% it's quite normal (2.7)."

"If you are pedalling slowly, the bike it's going to stay around sag like any other bike and work the same as any other bike with 120% of Anti-squat. If you start pedalling really hard it's going to extend, top out, and stay there for a while, because that LR (combined with that AS Curve) works "as a trap" for the rear wheel. If you hit something and you keep going the bike it's not going to absorb the bump, but I think that there is an instinct to relax a bit when you hit something really big, if that happens the suspension can react to the bump."

So, interestingly i) there is an extensive effect from pedalling (which I didn't expect) but ii) it is largely due to acceleration and an aggressive anti-squat curve and not at all due to the effects of chain tension, except insofar as the latter causes the rear wheel to turn and the rate at which it turns as well as an aggressive LR curve that complements the aggressive anti-squat curve with a very stiff pre-SAG LR spike stiffening the ride even more and finally, as I already suggested iii) the extensive effect seems to serve a purpose that is probably ill considered.

That all this can appear to be the effect of chain tension arises from the fact that the anti-squat kicks in when a rider really get on the pedals at or around SAG.
  • + 2
 @stillunimpressed: so there's NO shared nature. Apart from the altering of stiffness depending on chain tension in pedalling. My assometer says different in the real world but keep flinging those numbers about I'm sure you right somewhere but not necessarily in a relevant way to how it actually works when riden. Numbers aren't everything. Humans can adapt and alter to get the best out of something sometimes subconsciously sometimes not. And it seems @richardcunningham mtb tester of I don't no how many bikes suspension sytems and years says the ideas got legs I'm inclined to agree especially having riden a extremely similar idea bunches same guy for years.
It a couple of extra bearings and some links instead of a mini shock to control it is the basic gist of it and that sounds good and reliable to me
  • + 1
 Bunches? Stupid phone. From
  • + 1
 The linkage is very very distantly related to the equilink in that there is another link in there somewhere. But the excecution and forces are quite different. Do a free body analysis of each link and you will see what I mean. But it is not a 6 bar linkage, the wheel path is controlled by a 5 bar linkage. Disconnecting the link is to allow you to see those forces as they act individually. When the link is connected, those same forces are continually modulating the spring force, softer or stiffer. It IS POSSIBLE for a suspension to go to full extension purely from chain tension induced anti-squat. Take a ride on an early Cannondale Super V to see what I mean. But those bikes would also compress into, what you call, their natural state, at the dead spot in the stroke because that's what too much anti-squat can do. The Missing Link does not do that, because it uses the link to modulate the frame force as opposed to relying on anti-squat. Take a look at the videos showing the shock go to full extension on a steep climb. It does as I claim. And when the wheel hits the roots at the top of the climb, the shock absorbs the bump and then goes back to full extension to finish the climb. By the way, Linkage is not the best tool to use when analyzing this linkage. It is a canned program with limits to what it can do. Do a free body diagram and calculate the forces through each link. You get a much clearer picture than anti-squat curves and leverage ratios. You get to see what's happening.
  • + 2
 @stillunimpressed: So, after the two links, (the one above and the one below the upper shock mount) are vertical and "locked," explain what action triggers their release, and where that force originates.
  • + 0
 @tantrumcycles:
I have not said at any stage that a rather unique management of forces couldn't have been achieved by the Missing Link. What I said was the linkage can and should be analysed in conventional terms because it is a 6 bar linkage. You are now publicly stating it is a 5 bar linkage but anyone can count them and after counting them will conclude otherwise. Regarding the conventional analysis of the linkage, I have already deferred to Vrocks analysis (I provided the link) and acknowledged that it is possible for a suspension "to go to full extension purely from chain tension induced anti-squat." And, indeed that is what is happening here. Chain tension induced anti-squat lies at the heart of the way this linkage works and a very low pre-SAG leverage ratio also features and firms up the ride in the way you have claimed. Still, it would be a fantasy to claim that chain tension on the Tantrum bike works like it did on the Magic Link bikes. On those bikes you could actually effect a small change in the dynamic geometry and wheelpath of the rear suspension. Nothing like that is possible with the Missing Link. That you are employing anti-squat to achieve certain functional characteristics of the suspension and (with the support of an LR curve that complements the AS curve) a ride performance that makes these newer bikes similar in feel to the older Magic Link bikes is part of what makes your new linkage, per the optimisations you have sought, interesting. That I am somewhat disapproving of those optimisations, ought not be something that bothers you. If I were you I would want to be taking credit for the unique AS curve and LT curve that you have crafted and how you have been able to emulate the feel of the older Magic Link bikes, without any of the compromises of such a design. And it is clear that the AS curve and LT curve are not accidental so it is strange that you fail to mention them. Meanwhile, people are describing what you have achieved in utterly mystified terms that obscure your actual achievement.
  • - 1
 @RichardCunningham: Let me say initially that I have not claimed and do not subscribe to the notion that anything gets locked out with this suspension. It would be a strange if I did because I have stated very plainly that, per my understanding of things, it is an excess of anti-squat that explains everything about why the bike extends towards, or goes all the way to, top out. Naturally enough then, once acceleration is removed as a factor affecting the suspension, e.g. the rider stops pedalling or during lulls in acceleration while pedalling, the bike will start returning to SAG for all the normal reasons, which apply to any laden bike.

Perhaps, you imagine there has to be a more dramatic "triggering" condition than that, where mechanical effects arising from chain tension are removed before the suspension can start to move back to SAG. Well, I take it we would agree that ceasing pedalling, at least, will trigger the return to SAG even if we are inclined to make some additional points about this. I think you may be sadly disappointed in the hunt for some mechanical force, somehow exerted though chain tension, that could hold the suspension in a topped out state, for a linkage like this, except insofar as that chain tension leads to a surfeit of anti-squat. You must already be aware that believing in such a force or effect is totally inadequate. You must be able to explain how it works in sensible terms before you can expect anyone else to accept your account of things. I welcome such an explanation but so far I haven't seen one.
  • + 4
 @stillunimpressed: When defining a linkage, you must define it in terms of the input or output you are looking for. With the Missing Link, it is a 5 bar linkage controlling the wheel path and axle kinematics. Why not 6 bar? The 6th bar you see could be completely eliminated in terms of those parameters. It has no effect on the axle path whatsoever.

Remember the old argument about 4 bar vs. faux bar. The faux bar was indeed a 4 bar linkage in the general sense, BUT, it was a 2 bar in terms of axle path, basically a single pivot.

So if you are trying to evaluate this in terms of a 6 bar linkage, you will get seriously flawed results.

Which brings me to vrock. I have pointed out to him some serious errors in his analysis. He prefers to believe his answers. They do not reflect the way the bike actually behaves.

Is this not your quote

" Also, a claim is made that chain tension from pedalling can hold the linkage in a position that keeps the rear suspension in a fully extended state. First, that claim doesn't amount to much because for a bike with a properly adjusted SAG, there is no amount of chain tension (that can be generated by a rider) that can somehow lift the bike up and hold it there when its natural tendency on the contrary will be to return to SAG"

Are you not there basically saying that what I am claiming cannot happen?

Chain tension, pedaling effort, yes. They affect the bike much more like the Magic Link than a traditional AS effect. No, there is not an additional degree of freedom, but the similarity is in the way the horizontal forces on the chainstay, fore and aft, modify the spring force. This is just not possible with any conventional design, or any AS or LR curves.

I do mention LR, but in a way that matters more to the rider. The LR, in isolation, is meaningless. Just read how many bike tests mention they wish the shock had a larger or smaller air volume. This is ALWAYS because the LR and air spring curve are not well matched.

So instead of using LR as a defining factor (it plays a small part), I am using the wheelrate, which is the actual force to compress the back whelel under varying conditions. This is a performance parameter that really matters. And the Missing Link allows me to modify that for conditions in ways that conventional suspension cannot.

You are correct in your point that some of the parameters I am using are to help it emulate SOME of the desirable characteristics of the Magic Link. The pedaling support of the Missing Link does allow me to have a falling rate for the first part of the travel, for exceptional small bump performance, especially when combined with the Missing Link's "softening effect". But the Missing Link goes further. It allows for full extension, for maximum geometry change while climbing and maximum stiffness, for absolute hardtail effect on a smooth climb.

So, while you and vrock have some idea of some of the effects happening, you are the ones obscuring what the linkage is doing, by trying to describe in in conventional terms, with conventional measuring sticks. Vrock, by his own admission, is also using a scaled photo (and a canned software program), which is fun for shiits and giggles, but hardly worthy of a serious engineering discussion in absolute terms, which was how he was presenting it.

Open your mind a little bit. Please do the free body diagram for yourself and get back to me.
  • + 2
 @RichardCunningham: This is the key. It is the horizontal forces on the CS, fore and aft. They originate at the tire/ground interface. At the moment the tire hits a bump, any bump, the first contact is not vertical upward, it is horizontal, rearward. When you think about it, this is the same fact that makes bigger wheels roll over bumps easier. The larger the wheel, the less horizontal component of force exists to retard the bike's forward motion.

I am using that horizontal force to trigger the release instantaneously. As the wheel hits the face of the bump, the horizontal force pushes the wheel and thus the CS, to the rear. That force is translated through the Missing Link into the top of the shock. In one of my videos, I liken this effect to a locked human knee, very strong vertically until you kick it in the back of the joint, at which point it buckles immediately. Same exact effect.

www.youtube.com/watch?v=uh44UMTOmB0
  • + 1
 @stillunimpressed:

Please keep in mind

1) this is based on a highly inaccurately scaled photo

b) it is a "conventional" analysis, i.e. has no bearing. It's in a vacuum

3) canned software with limited options for open mindedness

It's a good guess, but not quite right.

There is one comment that needs to be clarified. You seem to want to separate chain forces form AS. There are, in fact, the exact same thing. Right??? AS does not exist with chain tension. More chain tension,= more AS.

Of course you can have chain tension without AS, but not the other way around.

You also make a comment about the extensive effect serving an ill-considered purpose. Would you not agree that a bike with 64 degree static HT angle might climb better with a 68 degree HT angle? Do you consider that ill-considered ?
  • - 1
 @tantrumcycles: I seem to have made some typos - where ever you see LT curve please understand LR (or Leverage Ratio) curve was intended.
  • + 3
 @stillunimpressed: Brian Berthold will tell you himself that there absolutely IS a shared nature between the 2 linkages. How could there not be??? My design parameters, my motives, my goals, were 100% the same.

To use the horizontal forces available to me to manipulate the suspension for better geometry when needed and better spring forces for various conditions.

One important aspect of the Magic Link was to use those force to help create the same "knee action" effect that I described earlier with the Missing Link. Using the horizontal forces to modify the geometry and spring rate. The fact that I figured out how to do it by inputting those forces into the upper shock mount allowed me to

A) eliminate the aux spring/shock

2) make it lighter/stiffer/cheaper/easiertosetupunderstand

c) have infinite spring stiffness when needed

4) have more geo change when climbing.

In return, I gave up the extra degree of rearward axle path and the series effect of the 2 springs in action, both of which were a benefit on square edge bumps. Which is why you will see a Tanrum DH bike with the Magic Link. For pure bump performance, it can't be beat.
  • - 2
 @tantrumcycles: Further on the correct descriptive characterisation of the Missing Link: You would be aware that what the literature calls as a Stephenson I 6-bar linkage is also sometimes described as what would appear to be a 5-bar linkage stacked on top of a 4-bar linkage. That description seems eminently suitable as a description of the Missing Link. Do you find anything wanting in such a description? If not, it would be helpful if you followed the terminological convention and grant your link is a 6-bar. If you do find such a description wanting, you should elaborate why because without some compelling justification, it is hard to see why anyone should defer to your authority rather than that of the existing body of knowledge and literature. So, where do you stand on this?

note: for those not knowing what is at issue here or confused by how the same linkage might (without error) be described in different terms (and with differing apparent bar counts) all that matters really is i) are well all talking about the same thing as we use these terms and ii) do we all recognise the way wheelpath will be governed given the particular form of a linkage assembly (once we can be sure we are talking about the same linkage assemblies despite any terminological peculiarities).
  • + 0
 @tantrumcycles: The way responses to one another's comments are being ordered here is unnerving. I gave way (explicitly) on whether (a great amount of) extension could be occasioned by chain tension ages ago - you will see that acknowledgement in my second response to Richard Cunningham where I expressed surprise that the linkage apparently could successfully fulfil the design brief. That said, I am unhappy with phrases like "chain tension" being used in highly generalised statements that abstract away too much of the dynamic context. For example, you haven't been entirely clear whether we must assume bicycle acceleration in addition to chain tension or whether the same linkage traits express themselves even in lieu of traction at the tyre contact patch, and thus acceleration. That is not a frivolous question - tyres can rather easily lose traction where water and rocks, say, are found. And, you could understand if I was sceptical about whether any of the more notable behavioural traits of the Outburst's suspension could be realised in lieu of actual acceleration (and traction at the tyre contact patch). So, I would be grateful if you could elaborate on this?

Please do not wait for me to prepare and consider any free body diagram. I am a well informed lay individual with a special interest in bicycle suspensions not a mechanical engineer.
  • + 4
 @stillunimpressed: But WHOSE literature??? For some cannned software sold to enthusiasts? That's not the important literature. A linkage, for any pupose of evaluation, most be described int terms of an input or output of some point on one of the links. In the case of wheel path, this is a 5 bar linkage and can only be evaluated as such. There is no literature that can change that.

It it were a 6 bar linkage, the 6th bar would have some effect on the wheel path, and therefore any anti-squat/anti-rise characteristics the suspension might have. But it does not. It can go away for those purposes.

To call this a 6 bar is just as inaccurate as calling a simple pivot bike with SS/rocker driven shock, a 4 bar. For shear definition, it is a four bar linkage, however, in terms of axle path, etc, it is a 2 bar linkage.

This is not my authority. Standard engineering terminology that has been around for eons. I'm a mechanical engineer.
  • + 3
 @stillunimpressed: The thing is, chain tension, acceleration, pedaling effort, climbing effort, they're all the same thing. One creates a force that is transmited through the entire physical system. Those forces can be calculated anywhere along the line and they better agree with each other, no matter where in the system you make your calculation.

So, without the chain tension, there would be no traction, no acceleration. If the tire loses traction, so must chain tension be lost, as well as acceleration. In a way that is linked mathematically and can be calculated. The problem is that these terms get tossed about interchangeably. And while they are all inextricably linked, the effects by one force on another have infinite possibilities for modification.

So, once you know what the force is at any given point, whether it is chain tension, acceleration, torque on the crank, etc, you can calculate the forces anywhere else in the system with my beloved free body diagram. It's a lot of work.

The best term to use might be acceleration. This is a good representation of what happens will climbing. At a constant riding speed, you are accelerating uphill. The rate of acceleration is directly related to the stiffening effect of the Missing Link. This is also true of AS, just in a different way.
  • + 3
 @stillunimpressed: sorry I missed this earlier, because you make a great point. "Naturally enough then, once acceleration is removed as a factor affecting the suspension, e.g. the rider stops pedalling or during lulls in acceleration while pedalling, the bike will start returning to SAG for all the normal reasons, which apply to any laden bike"

This is EXACTLY what is does. In fact, you don't even have to stop pedaling. If you pedaling effort is reduced the sag will gradually and proportionally increase. As you reach the top of the climb, the sag will return to static level even as you keep pedaling to finish the climb. the stiffness will remain (until you hit a bump). But we no longer require an exaggerated steep geometry, so we let it come back to static for level ground.

The triggering effect occurs whenever a bump is encountered, whether on a climb, flat or descent. It is most pronounced at full extension, where it must be to absorb the bumps in a steep climb, so you can still have max steep geometry, max pedaling stiffness and yes, max bump absorption and traction.
  • + 0
 @tantrumcycles:
"You seem to want to separate chain forces form AS. There are, in fact, the exact same thing. Right???"

Anti-squat (on a bicycle and most motorcycles) originates with chain force/torque/tension but they could hardly be the same thing. For a chain driven vehicle anti-squat can always be broken down into two dimensions or components - the chain based component, which while necessary (it is where all motive force comes from for a chain driven vehicle, obviously) as a condition for the existence of anti-squat is not normally the key determining factor of actual anti-squat force, and another component based solely on vehicle and suspension geometry and kinematics that is both key to the determination of actual anti-squat force and must be present in order for chain force to become an effective component that is partially determinative of the actual anti-squat profile of a vehicle.

Very briefly, without traction and a spinning wheel, which are clearly not 'chain tension', but rather its transformed result (if we are lucky and things go to plan) we have no squat or anti-squat of any kind or in any magnitude and no way for the chain component to exert any effect - chain torque without traction doesn't generate anti-squat just a wheel pointlessly spinning on the spot and anti-squat is irrelevant in that situation. The implications of this are not only that we need traction and acceleration, i.e. a motive vehicle and not just chain tension, before we can meaningfully start talking about anti-squat, however. On the contrary, what this amounts to is that the vehicle geometry and kinematics based component, which is straightforwardly and independently calculable without knowing anything about chain tension must always be there as a background, i.e. modelled in terms of a fully realised moving vehicle with a rotating wheel driving forward and pushing against the vehicle chassis with that driving force mediated through the particular suspension linkage geometry, for the chain based component to ever gain any purchase or come to have any definable effect on the behaviour of the vehicle during powered acceleration.

So, no, AS and chain forces are not the same or at least it is misleading to talk in that way about AS, even granting that the direct relationship, increased chain tension = increased AS (magnitude) holds (where traction exists). AS is a complex phenomenon that gets distorted by trying to reduce it back to its origins. That it originates in chain force, like driving force and squat, as well, doesn't mean that it is validly describable within those terms. That point of view leaves out the key role of the rotating driving rear wheel and vehicle kinematics which are the conceptual centrepiece of a comprehensive account of AS (not only for chain driven vehicles but also chainless powered vehicles as well).
  • + 3
 @stillunimpressed: You are correct on one hand, but disconnect your answer on the other. Anti squat originates with the chain force, we have some tentative agreement on that.

In the next paragraph, you state, " chain torque without traction doesn't generate anti-squat". This is sort of true, except that there is NO chain torque without traction (excluding from friction) so thus no anti-squat force from the ground wheel interface, (although there still is an AS component from the direction of chain pull).

For any given system/suspension layout, would you agree that you can calculate the anti-squat force once you know the chain torque?

And we're not talking about chainless vehicles here, which obviously have no chain torque.

On another note from an earlier post, I apologize. I tried to correct my post but couldn't. From a classical mechanical engineer perspective, it IS a 6 bar linkage that drives the axle path. I made the obvious error of not including the ground link (frame) in my count.

But here are the classic versions of 6 bar linkages, including the Stephenson:

www.rehab.research.va.gov/jour/03/40/1/images/jinf01.gif

Take a look and you can see critical differences. The main one being that, in the linkages shown, there are 3 joints attached to the ground link and only 2 links which do not attach to the ground link at all. In the Missing Link, only 2 links attach to the ground link, the Missing Link itself and the main rocker. There are then 3 different links which are NOT attached to the ground link: the chainstay, the seat stay, and the link that drives the shock from the rocker. So, while it is technically a 6 bar linkage, it is not in the same genre as the Stephenson linkage.
  • - 1
 @tantrumcycles:
"...although there still is an AS component from the direction of chain pull..."
I'll concede that. I am being a bit over zealous in some of my formulations.

"So, while it is technically a 6 bar linkage, it is not in the same genre as the Stephenson linkage."
I have looked very closely at the Missing Link and can see no reason it wouldn't be considered a Stephenson I linkage, viewed from a classical mechanical engineering perspective.
  • - 1
 @tantrumcycles: 1) In your website there is this really clear solidworks image nebula.wsimg.com/2d36d0caa316c20182f533650a6b3d57?AccessKeyId=0ABA55171382F27F717E&disposition=0&alloworigin=1

2) Bearing friction is negligible. How can affect it in reality? You can take it in account for the most realistic calculations but the influence is minimal and the complexity will be very high.

3) If you don´t have the Linkage program, how can you say this? You can model the Missing Link properly (6 bar). The program gets the instant centers of rotation to get the kinematics. With a CAD you can obtain very accurately results. It also analyzes the entire system not every linkage independently, which could give completely different results and therefore conclusions far from reality.

And following Gruble's criterion it can´t be a 5 bar. You're not considering the frame. With 6 members and 7 joints you got 1 freedom degree, with 5 it isn´t possible. So this you say is a big mistake.

Anyway, it would be good that you publish your calculations and graphics to end this controversy, if not always remain the doubt that can be simply marketing.
  • + 0
 @tantrumcycles: One thing that must have some relevance to the behaviour of the rear suspension of the Meltdown and Outburst in different riding situations is shock tune. Things could hardly be otherwise, because, shock tune is something that has an impact on any and every suspension type whatever form of analysis we are inclined to use to account for the defining performance characteristics of the suspension linkage. So, despite the disagreement about the terms of such an analysis - I support Vrock's conventional analysis whereas you insist that a different approach is required to account for the Missing Link's performance characteristics - there is still a list of factors, e.g. spring rate and tune of the shock as well as the suspension geometry determined Leverage Ratio curve, that must be taken into account to get a fuller picture on observable suspension performance. So, in that light, I am wondering whether there is anything special about the shock tune on your bikes? If so, I would be grateful if could you elaborate on that.
  • + 0
 @MrBlackmore: Sir, I'm really not sure what your point is for #1. Also, #2? I personally don't use bearing friction and don't recall it entering the discussion.

As for #3, I've played with the linkage program. When I say played with, I don't mean that in a disparaging way, but it is a bit underpowered. I also find that software like that can lead to lesser understanding of the system, with more tendency to make errors of assumption or data entry.

It is a 6 bar linkage.
  • + 1
 @stillunimpressed: Regarding shock tune. 1) I am able to ditch almost all of the low speed compression damping. I'm estimating 60-70 % of this is for pedaling only, simply to dampen still over active suspensions. The Missing Link does not need that at all, so I can have a shock with a much softer small bump response. But, this is not necessary, just that I can take advantage of it. The design still demonstrates it's traits even with a shock of conventional tune.

The other change is the low volume air can. This is to provide a rising rate when the liknkage goes linear for the last half of the travel.

Aside form those 2 items, I can use a much lower cost shock. I may even offer my own, even though that is a high market risk.
  • + 0
 I know Solidworks is expensive, but maybe we can start a Kickstarter to buy a seat - with the Motion Analysis plugin - for this Brian guy* so he can understand why this silly design doesn't do what he thinks it does. Hint for future napkin-sketch suspension designers: Any time you are modeling forces as acting in a straight line (like the extra pivots here) you are doing it wrong. The fact that RC signs off on this should be the dead giveaway that the emperor has no clothes.

Want to isolate the pedaling and braking from the suspension? Minimize chain growth and move the axle (more-or-less) perpendicular to the chain tension under pedaling. Tweak the leverage curve so that (when coupled with a properly matched and tuned shock) you have the highest leverage in the sag position - giving you the best rear wheel traction. I like lower leverage curves because the provide a larger tuning sweet-spot and are more forgiving of heat, but they come with a slight weight penalty and more sticktion. (...which the higher leverage in the sag zone mostly negates)

A Dual Short Link design (VPP, DW Link,etc.) gives you the most control over the leverage curve and axle path, plus lots of options for shock location and orientation. A Single Pivot with a linkage-driven shock can work just as well, but can be trickier to get the right leverage curve without taking up the whole front triangle. The big advantage of the Single Pivot though, is that the pivot itself can be significantly stiffer and more reliable. One large axle with large bearings will always be a better choice than 8 smaller bearings - all trying to work in parallel, but subject to manufacturing tolerances.

Unless your bike has rear cantilever brakes, there is no reason to ever put a pivot on the chainstays, near the dropouts. For some reason, almost 30 years ago, the idea that maintaining the relationship between cantilever brakes (this was pre-V-brakes!) and rims by connecting the dropouts to the seatstays got conflated into the idea that the "Horst-Link" magically isolates braking forces.

Nowadays the "Horst-Link" bikes are only useful for seeing which brands actually employ suspension engineers vs. designers who send .jpgs to China. More pivots = more flex = more weight, shorter service life, etc. If you really think you need an extra pivot to achieve the magical axle path you've dreamed up (you don't. you are wrong) just stick it up near the bottom bracket, (Dual Short Link) and at least you'll have the benefit of a stiff, one-piece rear triangle.

*I'd suggest buying a second Solidworks license for RC himself, but after 25+ years of being completely wrong about bicycle suspension, I don't think he's interested in actually learning anything.
  • + 1
 "this Brian guy" LOL
  • + 2
 Congratulations on speaking intelligably about suspension linkages. Its not a very good strategy to survive a popularity contest but at least knowing you spoke truthfully is a small consolation.
  • + 7
 Solid works isn't necessary for this analysis. Just a basic book on linkage analysis. well, that and access to the frame so I can measure the lengths of all the links. Without the real lengths of all the links you cannot actually analyze this suspension linkage.

You like Dual Short link bikes. That's awesome, so do I! but that doesn't mean they give the designer the most control. A horst link and a short dual link have the same number of pivots in the rear, four.

Why can a single pivot be stiffer and more reliable? just because there is only one? Why not use those same stiff pivots in 'more complex' designs? this really doesn't make much sense. Sounds to me like you have some preconceived notions about linkage design, bearings, and how linkages work that might need be let go.

Am I sold on this as the new best? nope. But I want to at least ride it before I declare it to be marketing BS.
  • + 2
 @gaberoc: The advantage of a Dual Short Link over a Horst Link is that you can have a unified rear triangle, mitigating the flex introduced by the extra pivots. Also, the shorter links are by their nature stiffer. With a Horst Link, you have 2 rather long levers (in the form of the seatstays and chainstays) that are supported only by the pivot bearings/bushings. This will always be either heavier or flexier or both.

Keep in mind that the lateral and torsional stiffness I'm talking about is not some idealized property that you want to beef up just for bragging rights. It has very real effects on the operation of the suspension and durability of the design. Flex effects bearing alignment and adds friction. Since most pivots in a bike's rear suspension only use a few degrees of motion when in operation, a tiny bit of misalignment gets amplified as the same section of the bearings/bushing take all the damage.

This is why I favor a single pivot design. (...with a linkage driven shock, of course) One big axle with big bearings will always be easier to keep in alignment than the 8 (or more) pivots in a Dual Short Link or Horst frame. It's also much easier to get the desired stiffness and strength in the bearings and swingarm. Not as sexy or patentable, and getting the desired axle path and shock placement are trickier, but much more practical.
  • + 5
 Please, please, please, upgrade my solidworks seat. '09SW is, well, '09SW. Maybe about 10k to my paypal account please, skip the kickstarter.

But you know, '09 SW is actually pretty good. And the information is there to calculate whatever you want. I prefer to do do direct analysis than rely on canned software, at least for the kinematics. You develop a tendency to understand the answers much better. Like when your math teacher made you derive equations.

In the end, the math doesn't matter if it doesn't ride well. If it doesn't do what I want, what I say it will do. And it does. Do you think I would come out here and have RC rip me to shreds for wasting his time? I don't mean that in a bad way, but the man has been around bikes for a long time. I may not agree with everything he's ever said, but I knew he'd give me a fair shake and tell it like it is.

You're kind of missing the point (or the link, HA) to the whole design. I DO NOT want to isolate the suspension from pedaling forces. Exactly the opposite. But the key is, how to use those forces. For what part of the travel? and how much? I chose to use those pedaling forces as a proportional measure. Certainly on a climb, you would want some increase in rear stiffness, right? At least to combat weight transfer to the rear? Can we agree on that?

And what about geometry? All things considered, would we want a steeper geometry for climbing? Especially with a 64 degree static HT?

So, my goal was to use the pedaling forces proportionally, to provide these benefits WHEN NEEDED. Again, that is the key. Those goals cannot be accomplished with dual short links, or any other links. They just do not use the forces in the necessary way. Because they can't. The layout and design of the linkage does not allow it. If it did, they would.
  • + 3
 @anoplura: There are no extra pivots in a horst link design. Dual link has 4 pivots. Horst Link has 4 pivots. With a dual link bike the "unified rear triangle" is a 'rather long lever' that flexes, which is only supported by pivot bushings/bearings. From a flexing/number of pivots/length of levers perspective they are quite similar.

I don't understand why you think it is 'easy' to get proper alignment on a linkage-driven single pivot, but 'hard' to get it on a 4-bar. It's the same amount of effort. Many single pivots bikes (kona, scott, ect) have the same number of bearings in their single pivot design as a horst link. Or do only the pivots along the chain stay count toward flexing on the rear triangle?

I agree that Dual Link offers some nice advantages, (and I think this missing link might offer it's own set of advantages) but i don't think that bearings on the chain or seat stays are bad or a poor choice.
  • + 2
 @anoplura: I realise this is a bit late but dear god please stop with the pseudo-physics. You clearly understand very little about the actual kinematics and vector calculus associated with suspension design. You are correct that when companies claim their design isolates breaking forces from the suspension, they arent telling the truth, but what designs like fsr acheive is actually very simple and effective. The break caliper is attatched to a member that does not change angle throughout the suspensions travel preventing the caliper from rotating around the disk. This means that the suspension does not lock when the brake is held. Anti dive is quite different however
  • + 1
 @anoplura: excuse my spelling of brakes and braking i only just noticed
  • - 1
 @Dhminipinner: Very, very wrong. First, read my explanation above about where the "Horst Link isolates braking forces" comes from. I was there. It had nothing to do with rotation of the rear wheel or caliper.

Second, the rear brake is not acting on the rear wheel in a vacuum. Yes, there is some rotational force acting on the caliper/seatstay/axle, but the greater force is the wheel acting on the ground, and vice-versa. The second greatest force is the rider's weight. Floating brake calipers, Horst Links, and rear pivots concentric with the rear axle are all - as they say - jive.

There is no way for a brake - acting only on the rear wheel - to lock out a rear suspension system.

I understand that for many people this seems counter intuitive. It took me a while to figure it out, too. Luckily, I started playing in mountain bike suspension in '89, and wandered into a career in engineering. Still, I didn't really get the idea that axle-path tricks are mostly bullshit until maybe 5 years ago.

It's not the easiest read, and there are a couple points I quibble with, but the Path Analysis site has some great info. Start with their "mirror bike" thought experiment, and dig in from there: members.home.nl/vd.kraats/ligfiets/pa/pa34.html#TheNaturalMirrorBike
  • + 4
 @anoplura: Sorry, anoplura, you are missing in action on your comment about floating brakes. I had a mechanical demo a few years ago that had a floater and non floater mounted to the same swingarm. You spun the cranks and hit the brakes. The non floater brake made the wheel jump up (with a very light spring). The floating brake just instantly stopped the wheel, with no movement at all.

Would you care to explain this in light of your above comment that Floating brake calipers are jive. You might also ask J Tomac how it kept him from ejecting over the bars on his lawill bike or how the Giant DH team did a back to back test at Big Bear before a big national. They loved it, but decided to race without it to save weight. After one practice run, they all came back and put it on for the rest of the weekend, even though they didn't want to. Oh, yeah, maybe ask Fabien Barel and Tracy Mosely why they lugged that useless thing around winning world DH championships.

If that doesn't work, try some free body diagrams with an open mind.

cheers,

b
  • + 3
 @anoplura: I remember that website you listed from back in the day. Funny, one of the guys listed (in 2001) is now claiming the Missing Link is bogus. Just can't take some people happy, but it's all adding up now. Maybe some long simmering wounds.
  • + 2
 Looks good. I'd love a long travel bike with HT like pedaling without having to lock and unlock the shock. Send one my way. I'll let you know what it's capable of.
  • + 1
 This is interesting. The choice in graphics however is hideous. This might be subjective, but I think many will agree with me when I say a "less is more" paint scheme would fit them best.
  • + 0
 Without live action videos of the suspension working (and not while pedaling) this review is nothing but a friendly press release. The forward and aft motion of the swingarm sounds very problematic in rooted out sections of trail that you can't just either pedal or coast all the way through. Not mention what's the life of those lowest pivots like? What's the hardware involved, I really hope it's off the shelf stuff I can easily buy online or at the local mtb centric shop.
  • + 2
 I have plenty of live action video without pedaling. Through that same rock garden as shown on our website video. At a pretty good clip. But that's the relatively easy part.

That's why I posted videos of pedaling through that rock rock at low speed/high effort. To show that it is active while pedaling. When needed. But then on smooth climbs, infinitely stiff and at full extension if the climb generated enough effort.

I specifically quizzed RC on any feeling of pedal kickback or feedback. He said he never felt any at the beginning of the ride and never even thought of it after. And this ride was ALL rock.

Pivots are all standard bearings.And so far, very good life.
  • + 1
 @yzedf: yeah, that's another good argument for why it doesn't work as is claimed.
  • + 1
 @b26-4-Life: but there's no argument like reality. It does.
  • + 1
 Just curious, if it locks out while pedalling, but becomes soft on a bump, when you pedal while going down, does it lock or stiffen up? Is it possible to have it lock while pedalling down?
  • + 1
 Cover the linkage up with some kind of cowling type thingy cos it's old hat.supercool paint and graphics,xt groupo.decent ad campaign..don't see why not if it's a shit hot ride.
  • + 4
 its like i just googled 1998 mtb...
  • + 4
 TANTRUM!!! "shreds pillow in half" - HIMYM
  • + 0
 i don't get the ugly comments. i think it looks fine. interesting system sounds good. replaceable dropouts, plenty of room for a water bottle, straight seat tube, lots of standover(more would even be better), nice numbers especially the 9er. i guess my only concern is a lot of pivots. i hope that main one on the link is huge. wonder what the frame prices will be?
  • + 2
 I'll design graphics for free as long as you don't make the production bike with those god awful graphics, cheapens the look of the bike.
  • + 1
 Pantone 871 C. Done
  • + 4
 With a new paintjob / decals it would be a pretty nice bike.
  • + 4
 That is super clever!
  • + 2
 I never thought i would see my old kona Coil Air 2011 on Pinkbike again. I call it squeaky link. it keeps falling apart.
  • + 2
 First bike I have seen other than the Evil Insurgent and Canfield Jedi/Balance that I actually want to buy.
  • + 0
 Yeah ,lose the screaming face and the sissy stripes and I just might buy one. If this is gonna be a game changer it's gotta look more professional. Sorry, but I'm a fussy toolmaker.
  • + 1
 single pivot with a rising rate linkage connected to the shock... state of the art for 1989 cr 250... I'm sure it works great.
  • - 1
 Looks like a failed experiment from the 90's, like linkage forks & oval chain rings. We got enough gimmicks floatin' around here now bud, some even clawing their way back from the dead.

Even if it weren't gimmicky as fvck then it's still ug' as FAAAAAAACK! Everyone loves a superficial pivot or two on their concraptions nowadays though don't they? Just needs a bright yellow Girvin up front for a full deuce. Just lookin' at it makes me wanna hissy. :/
  • + 1
 The thing could look better but it is not a gimmick. Having lots of pivots is the consequence of electing to use a 6 bar linkage. Do you get anything in return? The information compiled by Vrock shows that the main suspension parameters of this bike are rather unique. You can see that information at
forums.mtbr.com/all-mountain/new-inovative-suspension-tantrum-cycles-any-thoughts-1009862-2.html

You have to judge for yourself whether the unique linkage characteristics and suspension behaviour, described on this page and the Tantrum website, are beneficial for your riding and whether any gains outweigh the costs.
  • + 2
 @stillunimpressed: Please keep in mind, by vrock's own admission, this was off of a poorly scaled photo. It is highly inaccurate.
  • + 1
 @tantrumcycles: For the time being I am happy to have an indicative picture of the AS and LR curves. I imagine that Vrock will eventually publish something on the linkage design blog and by that time, I expect, the accuracy of the graphs will have improved.
  • + 3
 Thoughts on the reach, seem a little short compared to current standards
  • + 1
 just what we need, more standards.
  • + 1
 Updated reach numbers S- 400. M- 435 L- 470
www.tantrumcycles.com/meltdown.html
Looks good to me
  • + 1
 Something else...put at work to the painter/designer of the Blue Tempest Rays Klein...it deserves a comeback !!! Go for it !!!
  • + 1
 @RichardCunningham It would be good if you guys could build one of these to your spec and ride for a few months. I see this as being a real game changer.
  • + 0
 still would have to generate a huge amount of anti-squat and pedal kickback to extend the rear to the locked position while pedaling, but i guess as it's actually locked out then pedal kickback isn't an issue?
  • + 0
 I have a lot of steep out of the saddle climbs and are fairly smooth in my trail system, so a bike like this seems like a perfect. Just don't like the idea of replacing all those bearings.
  • + 3
 QUICK! Patent that before Spesh sees it!
  • + 1
 I have always been fascinated by people wanting a full sus to feel like a hard tail. I prefer plush .up and down. to each his own i guess
  • + 2
 Very interesting, I would like to ride one at some point. Wish it had 60mm or more extra reach in the largest size
  • + 2
 Well, if can handle Simi valley up's and downs. It sounds like a solid bike. I would love to give it a go!
  • + 4
 That man is a wizard
  • + 2
 Could be the best suspension platform ever, but looking like that, few bikes will be sold.
  • + 0
 90s are over. No need for new suspension designs. Few popular ones work just fine and cover all use cases. Not that much difference between good ones anyway as far as measurable performance and comfort.
  • + 1
 Not pretty, but very interested in riding. Looks to lock out really well on pedaling forces. The head badge has to go, it's hideous.
  • + 3
 1990 called, they want their graphics back.
  • + 1
 I have no plan to change my bike at the moment but when I do this will be top of the list. Hopefully, at that time it will be going strong.
  • + 1
 Great innovation and creativity. Hope everyone's paying to where they should be taking their designs.
  • + 1
 As good as the review is how many pivots and links does a bike really need?
  • + 1
 Wonder which bike holds that record? My guess Scott gambler
  • + 3
 That's so cool!
  • + 1
 All the kinematics and free body diagram posts of yesterday were removed? What the hell PB?
  • + 1
 Actually that looks very interesting indeed! I would love to ride but please let someone else choose the paint job Wink
  • + 1
 Can the chainstay length be shortened in this suspension design? Just curious how the chainstay length was selected.
  • + 3
 Cool!
  • + 1
 @RichardCunningham Any chance they are looking for people to do some long term testing on those beasts?
  • + 1
 An Engineer's bike for sure, functionality taking priority over appearance. Sounds pretty damn functional to me!
  • + 3
 I like it.
  • + 0
 Make an XL in the 29er, price the frame reasonably and I might buy one, especially if I can use the pike and wheels (non-boost) off my current bike.
  • + 1
 Edit: I know the little video show's it but I would like to see in field application
  • + 2
 There is a link in the text to a rough-cut video that Brian shot which shows the suspension in action.
  • + 1
 @RichardCunningham:

In the video, when the pedal load locks out the suspension, the "missing link" appears to lock itself out by resting itself "enthusiastically" against the seat tube with a metallic "clunk" that would become worrying after 20,000 cycles...?

Did you notice this happening out in the field as the shock fully extends, or does the shock limit the movement of the linkage to stop it hitting the seat tube?
  • + 3
 @orientdave: No, the shock tops out and prevents the link from contacting the frame. Brian removed the shock in the video to illustrate how the two links lock and unlock.
  • + 1
 I wouldn't mind one of these for my next bike project.
  • + 1
 I'm just waiting for Protour...
  • + 1
 I'm having a meltdown with my tantrum

*ba-dum diss*
  • + 1
 Ellsworth has some new competition.
  • + 2
 Mh. Strange.
  • + 1
 A better Mantra. Meet the Tantrum.
  • + 0
 The paint job, decals, and frame shape are very WalMarty
  • + 0
 The '90s just called...They want their bike back
  • + 0
 IKR?!
  • + 1
 Kaboom!
  • + 0
 Love the design ,what's the price on frames?
  • + 1
 "Pricing: Available in July 2017"
  • + 2
 @XCMark: Pricing should be finalized soon.
  • + 1
 hey!
  • - 1
 Can we get a comparison to other innovative linkage systems: Canyon Strive, Yeti SB's etc.
  • - 1
 Lol people need to leave the designs alone ffs..looks like ass!! Spew bag included??
  • + 0
 Doesn't matter what frame you use, x-fusion feels like poop
  • + 1
 Don't put it up your ass.
  • - 3
 i counted 6 pivots on the rear triangle alone and the name...... ,,,,,,ya the name means it will destruct and you are beat. re think the name dude
  • - 3
 The real question for me is why would I want an fs that doesn't work when it's being pedaled?
  • + 5
 But it does. Go to his website it shows some vids explaining it and showing it in action
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