To The Point - Rake and Trail

May 21, 2013 at 0:09
May 21, 2013
by Matt Wragg  
 
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Murray Washburn started out racing BMX when he was five. He went to college in Colorado, where they issue you a mountain bike when you hit the state line, at the time when mountain biking was in its infancy. He worked as a shop guy in Colorado for many years, in sales and service, working with racers and wrenching for racers. In 1997 he started working for Cannondale and has held a number of roles since then, including sales representative, race mechanic and product manager technical representative. Today he is the Global Director of Product Marketing, which is the link between Cannondale’s Engineering dept and the outside world. He describes himself as a "supremely unqualified engineer, but someone who loves knowing how stuff works."


What is a fork-offset?

When you're talking about geometry and handling, there are three things that are interrelated.
First there’s head-angle, which is the angle of the head tube. If you a draw line right through the head
tube and steerer tube and take that all the way down to the ground, that's your head angle. Then there’s
fork rake, which is the amount the front axle sits off that centre line.For mountain bikes, it can also be
referred to as fork offset. It's been hovering around 45-50mm of offset.you can gain fork rake either through
angling the stanchion tubes at the crown, or offsetting the dropouts, but the net result is the same Rake
and offset together create a measurement which is called trail. This is a measurement where you take
that head angle line extended to the ground and then you find where the axle is and you draw a line
vertically down to the line. The difference between where the first line and the second line intersect the
ground is called trail.

Supermax diagram

Why should people care about this?

There is no easy way to think about rake and trail, because if you go too far one way, or too far
the other, the affect flip-flops. From a mountain biking standpoint, the easiest way to think about
is that head-angle controls and affects high-speed and low-speed stability. Meaning, the more you
rake it out, the more floppy to one side the bike gets at low-speeds, the more of a handful it is on the
climbs. But,when you're travelling at high speeds, it not only aligns your suspension with the oncoming
impacts, but gives it a really planted, solid feel that makes it hard to maneuver it off line. When people talk
about slack head-angles, they generally refer to it in relation to 45 to 50mm fork offsets. If you think
about what the demands are for all-mountain riding, you want a bike that's really stable at speed,
but you also want it to be maneuverable when it gets slow. You look at enduro riding, where they've
got massive high-speed sections, but they've also got tight hairpin sections, quick little uphills,
you've got all these different things. The idea would be that you've got a bike that has really nimble
handling at low speeds, but is rock-solid at high speeds. We've been playing around with different
head-angles and different fork offsets to achieve that.


How do you apply this to your bikes than?

The most obvious example is the Trigger 29. We took what is normally 45 to 50mm of offset, and we push it out to 60mm of offset. If you look at the SuperMax axle, you can see that there is a big offset of the dropout there. What that does is allows us to kick the head angle back to a relatively slack, 69 degrees, which if you kept that with a 45-50mmmm rake on a 29er, you would have the most sluggish handling bike in the world. It would be great at high speed, but the second it slowed down it would just be a pig. By kicking the head-angle out and kicking the fork rake out, it does the counter-intuitive thing of reducing the trail.

If this is so vital, why isn't this something we hear more about?

Most bike manufacturers design around industry standards and creating change within that world is slow and difficult. Suspension manufacturers build forks that are consistent to each other based upon OEM stuff and, like everything in mountain bikes, people accept things as standards and rarely think about them in a different way. Cannondale is a frame and suspension company first and foremost and we have the unique ability to change angles where we see performance improvements.

Doesn't a slack head-angle just mean poor low-speed handling?

If the head-angle was the only factor, the answer would be yes. Thankfully though, this stereotype
is just that. Handling is one of the things that, up until now, has been holding back longer travel 29’ers. 
At low speed, there is a natural tendency for the big wheels to be sluggish. Frame designers have been
using steeper head angles to help, but it was at the expense of high-speed stability. That is not a lot
of fun for a bike that naturally wants to go fast. By adjusting both head angle and trail, you can get a
bike that handles just as incredibly well at high speed as it does at low speed.

Photo courtesy Cannondale

Ben Cruz aboard a Cannondale Jekyll with a prototype SuperMax.


Why don't you just eliminate the trail then to make slack bikes that handle incredibly quickly?

You need trail to offer some stability to the bike. Without it, the front wheel would behave like the wheels on a shopping cart. It is the balance of these subtle ingredients that separates great handling bikes from the rest.
  

Cannondale
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140 Comments

  • + 76
 You don't need a Cannondale brochure to teach you about rake and trail - instead, just start mouthing off on an MTB forum about how frame X isn't slack enough and some jerk will blow his lid about HA vs rake/trail and school all your arses in proper bikeology.
  • + 6
 Hahaha jerks arise, true
  • + 10
 Yup, I'm the jerk. Too bad the actual science is measurable, predictable. When you build your own frames, this stuff is important. Do you want the explanation of the real science behind chainstay length, STA, and BB drop as well?
  • - 5
flag WAKIdesigns (May 21, 2013 at 8:33) (Below Threshold)
 Willie, if there was "real science" behind it, don't you think that all those companies would find the perfect geometry for each kind of bike, long time ago?

Even high-end 26" XC racing bikes were using slightly different geometries between different designers, before 29" armada came three years ago.

Spec is known for dialed bikes and even them released geometrical nightmare that P.AM was, at the time when they released the SX Trail wonder that finaly debeiged AM bikes.

Everything is about compromises and priorities: and some are f*cked like chain stay length on 99% of bikes being a result of keeping production price low. It costs double or even tripple to make a short CS and keeping it stiff and light. If you just draw a tube all the way to BB/pivot you can't achieve anything short.

Im tired of people making a big deal out of bicycle design when so many good examples are available for comparison.
  • + 3
 willie1, yes please. do it in this comment section too.
  • + 19
 Waki, all the numbers we use are compromises. We have overlapping variables that cannot be removed from the equation. If you have dead average torso length, upper and lower leg length, and reach, a stock bike will likely work pretty well with you. A do it all bike that climbs and descends equally as well needs to center the rider's weight between the axles. The chainstay length and front center need to work with the BB to keep the rider's weight in the sweet zone. Seat tube angle is less important for DH and BMX, but for seated climbing, it is important as it affects weight distribution. There is a certain wheelbase that is the sweet zone for this as well. Finally head tube placement is a reference point within 50mm or so, but is adjustable with different stems and bar rises.

Now- shorten the chainstays to stiffen the rear end, shorten the wheelbase, and improve rear wheel traction. You now changed your wheelbase, and center of balance. Your bike won't climb as well. No prob, slacken the HTA to lengthen your wheelbase. Slacker is better right? Wheelbase is now normal, but weight distribution is rearward. Climbing is compromised, as is cornering. Lower the bars to get the weight down on the front end. Better high speed cornering, but your breathing is affected on the climbs, and slow speed cornering is off. The front wheel flops on slow corners and climbs (the trail is off, your body is in an awkward position, mechanics are off, excepting high speed declines, except the low bar shifts your upper body weight forward.
  • + 4
 I haven't even read this yet, but thanks Smile
  • + 7
 It keeps getting better. Since you no longer have the stability you had, you must kick out the front end another couple degrees, which stabilizes the downhills, but the trail is getting excessive, compounding the climbing and slow speed cornering. MAybe we should shorten the chainstays again to shorten the wheelbase. That will help cornering right? Wait, the weight distribution is getting worse. The front end feels vague. We need more stability!!! Lets slacken the front end out some more!!! and on it goes.

BB drop is very important. More BB drop generally allows a lower Cof G. The lower the C of G, the easier it is to get a bike to move side to side. This is offset by the gyroscopic weight of the wheels which want to keep you in line with the rotational direction. Larger wheels allow for more BB drop, at a certain BB height. The difference we feel with 10mm lower BBB height has more to do with BB drop than Cof G. This is a big part of the "magic" ride of the 650b. The BB drop, changes the relation to the wheel axles, keeps the C of G consistent with a 26er, the weight difference in the wheels is minimal compared to a 29er. Trail is more reasonable as we don't kick the front out quite as much, the rider weight remains more centered. There is more room to control rear wheel path than on a 29er, which would end up with a front biased C of G, as opposed to the 26er rear weight C of G.
  • + 2
 Willie - good stuff. i may add this: weight distribution is a very blurry subject because rider should be in neutral position, that is 99% of weight on pedals. Long TT eases up weight shifting as it allows you to do that more dynamicaly. Short chainstays do not compromise climbing as much as slack head angle which makes the front wheel wandering a lot. Slack is fine on fireroad climbs, but you won't get away with it on rocky path when negotiating between stones and roots. Problems with weighing front wheel on steepest gradients are non existent on my 405mm bike. You can also try to cover up the short cs with steeper seat angle but, that will compromise standing pedalling. Unless you run a stem that is 40mm or shorter, wide bars cover up for lack of stability of a steeper HA, what is often overlooked. In my honest opinion short cs gives you more by easing up pop the bike into the air and manualing that it takes from uphilling. Due to construction reasons and 2x10 chainsets using huge middle cogs requiring lots of clearance we don't see it almost at all.
  • + 6
 What happens to your front center when you lengthen the TT without going steeper in front end geometry? Overlapping variables. Short CS typically manual better, which is the last thing you want on an uphill. It all relates to all of the other numbers. Weight distribution is less important in MTB than road frames, as the rider does shift position a lot more, but seated climbs show us how the bike is balanced.

BTW, I didn't do the neg prop thing.
  • + 0
 I'm not a supporter of slack&low as my trails are quite slow and very rocky. To me, the head angle is something you design for speed the bike will be used at for most of its service. BB heights can go crazy mad low for a new school touch, if the bike is to be used for riding on machine dug trails with 165 cranks. People go a bit too crazy about slack&low for all sorts of bikes, as if someone found a fountain of youth, or a way for communist economy to work. One thing is true though that there are bikes that are hideous, long TT with steep head angle and high cockpit = fail as fk!
  • + 0
 My bike on 405 does not wheelie steep gradients, but I might have some technique fundamentals dialed and some sunday warrior might get upset if I sell it to him Big Grin I actualy wheelie often on purpose on technical climbs as it is an effective way of dealing with rock slab steps or larger roots. I also compromised by doing longer TT. But to me nothing screws up climbing more than sub 68 HA coped with high cockpit. If I switch my fork to 150mm giving me 66.5 HA, climbing even the easy rock gardens is nearly impossible. My next bike will have 399cs.
  • + 3
 @WAKI: I would not agree that "Spec is known for dialed bikes". Me, for one, do not like how they handle. And I am a fan of "Horst" link design for suspension.

What they are know for are the same thing as Cannondale - a lot of unnecessarily proprietary parts.
  • + 6
 @BigMedicine: You where saying?
  • + 4
 You guys have done a good job of identifying some of the challenges with higher order interactions which are further compounded by rider variability: inconsistent terrain, rider bodies, riding styles . . . This make finding optimal solutions very challenging. These types of problems have plagued manufacturing for a long time. One problem is we haven't had tools that can reasonably manage the literally hundreds of millions of potential solutions. Fortunately we have some relatively new tools available in computational statistics that are much more efficient at handling these scenarios where there are many variables and few observations. I use them daily in automotive marketing science and they are game changing, I hope some of these engineers hop on the wagon and increase the efficiency of the R&D work. Then again, maybe there are guys out there doing this already.
  • + 61
 I quite often have to rake my trail...
  • + 1
 When I read the headline I thought it was gonna be one of those trail building threads slating rake and ride trails.
  • + 7
 ...and you have to trail your rake to the work zone -- most riders forget this crucial step
  • + 54
 Psh, low speed handling.
  • + 13
 We don't need no stinkin' low speed handling!
  • + 1
 @Chainsaw, I see what you did there.. Wink Smile
  • + 20
 "(...)By adjusting both head angle and trail, you can get a bike that handles just as incredibly well at high speed as it does at low speed(...)"

That is off course true to a great point but let's not forget forks suspension performance. At steeper head angles the fork will not absorb high speed hits as well as a fork at slacker head angle, especially a standard fork that uses standard bushings unlike Lefty. While Lefty might cope better with a slider going into the bushings under side load, it will suffer a bit more from deflection, resulting in a slightly increased stability loss after bing struck by the bump.

So in case of a downhill bike going real fast where forces from bumps are acting on the bike more horisontally than on DJ bike particularly, the slack HA is a win-win. On an XC bike, steep HA and long rake is welcome. With Enduro bikes, sorry but we have few years to find the right compromise.
  • + 13
 .... - With Enduro bikes, sorry but we have few years to find the right compromise. - .... Haven't we had decent "enduro bikes since at least 2010 ? I think of these as the Trek Remedy's, Giant Reigns, Intense Tracer... Etc, Etc, Etc.... Didn't we just call an Enduro bike, and All-mountain bike ?? Or a 6inch trail bike ? I'd have to say I think all these 6inch trail bikes had dialed geometrys, light weight and strong build kits that you could have fun with at your local XC race and then go play at the bike parks with your friends. This was great until someone thought it was a good idea to introduce 29-ers to the world of mtn biking. Sure 29-ers for XC specific bikes doing nothing but firm flat ground. But whats really wrecked these sweet 6inch trail bikes are these goofy ass 650b wheels.
  • + 4
 pushingbroom - "Haven't we had decent "enduro bikes since at least 2010 ?"

I thought so not so long ago but closer the World Enduro Series came and more I thought about, then I saw vids from Punta Ala. AM bikes are dialed but Enduro will redefine it, because it will add racing experience to them. BIkes are surely being developed with that angle in mind as we speak but it will take two years or so until that research takes form. Geometry and even wheelsizes will be put to the test in the most professional way it has ever happend to mid-travel bikes. For now no one can say which wheel size will be the best one in 5 years. Now we have the pressure for 650B, but racing will determine if it really is the one to go. ENduro will also be the prooving ground for electronic suspension, and unless it gets banned, this is where we will see that steepest development curve. And who knows what will happen because of electronics - will it increase the travel or decrease it and thus alter the geometry? Will it improve the pedaling efficiency so people will be able to have more travel, or will it decrease is because suspension will deal with bumps better?
  • + 1
 Tracks will mainly dictate wheel size. If tracks were very tight and techo(narrow lines that needed to be linked etc), we'd see 26er having more of an advantage, But we won't and 27" will hold it's own against it anyway. 27" is the future I'm fairly certain. It's nimble enough, but has slightly better rolling ability, and slightly more traction cornering(not sure if this is at the expense of feel). This whole rake trail thing, for 27" is mainly marketing so we buy 27" specific forks. The benefits will be minimal, if even perceivable.
27" should make the good old ZERO travel hardtail with 4.5" forks gain some performance ground back, even against electronic blah blah.
  • + 4
 I want a frank, honest 1 on 1 with a pro who is racing on a 650b. The bb-hub difference seems a little beneficial, but how significant is it? The slightly larger wheels: do you think you'd notice the difference in a blind test? Does it wallow when excellerating? These guys and girls ride a lot on a variety of rigs. If the differences are small and mostly good I would bet we will see this wheel size become the standard for most riding. Unfortunately straight talk is pretty rare.
  • + 5
 I'm pretty sure Barel said 650b wheels were around 1 second faster per 3 minutes on a pre-EWS Punta Ala video. To me that difference is very small - relevant to a racer but not me personally. Yes, there is a difference, but I (perhaps wrongly - bring on the flaming!) believe most people who are 'blown away' by the handling of a 650b bike are unable to isolate how much of that is down to the wheels and how much the new frame/components. Like you said, there is no real comparisons of similar bikes with the only variable being the wheels...

Oh, and before anyone goes there I've nothing against 650b...
  • + 7
 @Slimboyjim - It was Nico who said it.
@taletotell - straight talk is rare indeed. Fabien Barel did more straight talk in the bike tech vid for DirtTV than many pros did in their entire career, probably all together. I cannot thank him and Steve Jones enough.

If there's so few people with such spine and balls like Fabien, the industry will feed people with threir usual BS and they will forget it, and tinker "geeky facts" vs "troll assumptions". I wish more people would talk like Fabien. Bike world would be a better place.
  • + 3
 The question is whether the gains will be just as small in case of your average weekend warrior. I can imagine top pro's being more able to ride 'around' the differences between bikes or wheel sizes than we are.

A local magazine here in the Netherlands (up/down Magazine) recently featured a test, doing timed runs on 26, 27.5 and 29er versions of the same bike. All were fastest on either a 650 or 29er but the least experienced rider gained the most on the bigger wheels. Obviously far from scientific but still interesting nevertheless.
  • + 4
 A valid consideration: there is a skill threshold afterwhich mechanical differences concede only marginal gains. I could see someone who tries to plow through everything on a 26 gaining a lot from a 29er. I know i am past that point, but maybe a 650b would feel right to me. I gotta try one.
But then again, maybe training wheels just teach bad habits...
  • + 2
 Yes, good "all mountain" bikes have existed since the mid-2000's. the Santa Cruz Heckler being one of the first. Followed by the Blur LT, then the Nomad (a true race bike), then the Reign, Remedy, Kona Dawg, etc, all around 2005.
  • + 3
 @ Wakidesigns,
If you want straight talk, Brian Lopes dishes it.
" Why are you riding a 29"? Because its a new bike and we want it to get as much camera time as possible."

Same video, Fabien is a great rider for sure.

Also note, this is not a slam on 29" bikes, it is more of a proof that racers don't always race what they want. They race on what they're paid to race on.
  • + 1
 Yes, off course sometimes they ride what manufacturers want them to ride. I don't think though that Brian did a team order. He's too big and Ibis is too cool. It was either being polite or he really felt fastest on the 29er. It's not a relation rider-manufacturer like for instance Santa Cruz and Josh B. Fabien really stuck his head out, even though he didn't have to. That's why I appreciated it so much.
  • + 3
 To WAKI's point, Lopes has much as said he's riding select races for the fun of it but will still try to win. He's no longer interested in titles. Ibis needs the Ripley getting exposure, so Lopes is doing just that because it's fun and a challenge and it's what the brand needs. If he really wanted to gun for the win and wanted to do so on an HD, he would have done such. Ibis is a *very* small company. They need Lopes more than Lopes needs them. No way they are "ordering" him to do shit. besides, they are super cool dudes, just is not at all their style to be agro and corporate and lay down BS directives.. That and Lopes is 43, he needs to be thinking in terms of the long term. Rep'ing the brand and providing more camera/people time at events is what will continue to bring in the sponsor contracts. He's a hall of famer, he doesn't have to win anymore, he just needs to place well, look good doing it, and be cool at the events.
  • + 1
 Pushing a losing design advertizes that it is a losing design, and losing isn't good for business.
  • + 1
 Bliss - tgat was more or less what I meant. Willie - yup! Marketing will erase DirtTV Bike Tech vid from Punta Ala from the memory of many of those who have seen it, and most of potential clients will never see it. Fabien might indicate that CTD and 15mm is not good for hardcore AM bikes, but after few press releases only few will remember. Off course unless Fox crtitque on board and brings back 160mm 36RC2 and offers it for both 26 and 650B. Im sure guys at RS who watched it, are going, shit we could give 20mm axle to the PIKE - 20g, who the f would notice...
  • + 6
 Willie - Ibis is a small company with small marketing dollars and a smaller race budget. Having Lopes in a big event pimping the Ripley is good soft marketing regardless of his race result. they simply don't have the money to market big. They have Anne, Lopes, and Even because they do win and are good ambassadors for the brand. The fact that Lopes took 15th against a stacked pro slate, most of which were European with much more SuperEnduro experience along with experience at the venue, at 43 on a 120 mm 29er is actually impressive. Those in the market for $6k to $10k bikes are not gonna say "oh, Lopes lost in the first Enduro World Series race, no way I'm going to buy the Ripley now."
  • + 3
 Bliss I agree with you. Lopes is 43 now? He's exposure for Ibis, not a future champion. Look what his videos did to open peoples minds about carbon with the original Mojo, tranny, and then the HD. Even X Fusion is an "acceptable" brand now that he's with them.

I'm commenting on the idea that the manufacturers push designs that are inferior to 26ers simply as marketing. If the product was inferior, it would lose consistently. If last year's champ has a hard time breaking into the top 5 after a team change the next year, the new company looks inferior. 29ers have won several lighter duty DH races. That in of itself shows they are not only XC machines. They can work in many arenas, and we will likely see DH 29ers along with the 650bs that are upcoming.
  • + 1
 Yep, agree with you as well.
  • + 1
 WAKI,

What are you yammering about? FOX makes a 2014 36 Float and TALAS RC2 20QR 26in forks...

Cheers,
Will-burr
  • + 1
 Not at 160mm of travel. Only 180 comes in RC2. I thought there is no 36 160 anymore. They were pushing RLC into 160 series since 2011
  • + 12
 All I got out of that is that is big wheels make it difficult to make a bike that is fun to ride..... Soooooo what was wrong with 26 inch wheels again ?
  • + 6
 They fall into holes easier, have trouble rolling over things as easy and have less traction. You asked what was wrong with them. Smaller wheels have many benefits too.
  • + 1
 Not difficult, but they don't use the same geometry such as HTA, BB drop, CS length, or trail. Don't compare a larger wheel geometry to a smaller wheel bike. The numbers won't be the same for two bikes with the saem purpose, but different wheel sizes.
  • + 3
 The problem is that they are SO NOT COOL dude! Just kidding, 29 is gay, and 27.5 are there just to rob our money!
  • + 2
 Caiokv is going palces guys.
  • + 4
 omfg..
so its harder to ride 26er compared to 650 b or 29er.
sure its hard to ride hardtail with 150 mm fork too. its fun that matters. and if you nail rough section on hardtail , its priceless.
its not bike but rider. 10% is bike 90% is rider . why buy new frames/bikes when you have not reached even 70% of bike potential? Perhaps because you can reach 65% of new bike potential that would be same as 70% of your old because geometry is more refined?
look at Chris Akkrig for instance. Wonder how would he stack in enduro race. he should try it too..
  • + 3
 He did start in some British Enduro and did the top 3 if not won the thing. I don't remember. He is a freak.
  • + 1
 From some of the statements above, we've learned that that bigger wheels are worse and 26 is the best.

So shouldn't 24" be even better?

Bzzzzttttt. No soup for you!
  • + 1
 @ iamamodel: you didn't actually read any of the article and posts did you? None of this was about better/"wost" but how the geometry needs to be adjusted for different applications to work together. In fact 650b requires the least amount of compromise in the design to get a balanced ride.
  • + 1
 Willie, check the first comment. But anyway, fair point. I'm just sick of people going on and on about wheels size, but they are thinking it all the way through. I should have put that comment on a different thread. Perhaps I will.
  • + 1
 But what is hard with getting a balanced 26er? Wheels are small so they are really easy to move around and 99% of the strangest user demands can be met with the use of straight tubing meeting at the joints, even in full suspension bikes, using almost any suspension design.

iamamodel: 24" will be more popular soon, as there's more and more die-hard riding daddys who will be ready to lash out some $ for more developed gravity-bikes for their kids. As soon as bigger companies will smell that market can recieve expensive small bikes, they will push more for kids to emboss their brand on them as early as possible.
  • + 1
 Waki, that means 26" is the 29er for little kids! ha ha. Or is it the 650b? I guess it depends on the size of the kid.

Someone needs to develop a person size versus wheels size versus intended use matrix. I think you are the person for the job.

Forget that frame you are working on, this matrix is what the MTB world really needs!
  • + 3
 Yes! And if you are 6ft high and want to ride a BMX you better pick a 26" one! Stop right now and ride what you are told by the people that know better than you! They have matrix for everything.

After a new bike? Just answer a few questions: First question: How tall are you, Second question: What is the size of rocks you have on your trails: give the smallest and the biggest (height above the trail level) - 3rd question: how would you describe your current bike:awesome/gay/not sure - 4th question Were you ever masturbating in your car when stuck in a traffic jam? yes/no 5th: have you ever masturbated only by stimulating your prostate analy. yes/no/thought about it - Thank you the D8 system will now process true facts with use of actual science and give you a nonsense free, logical answer...Processing... You should ride 650Bzzzzzzzzz
  • + 2
 Waki, its the BB drop that makes it harder to get the most out of 26" We are just used to the ride of a 26 so we don't realize how much better a bike with better BB drop can ride. After owning a road bike with dialed geometry, I realized the lack of refinement in my MTBs. The first ride I had on my 650b gave me a similar feeling to my dialed road bike. Nobody SHOULD ride anything, but on the other hand, no one should hold back the development of the technology because they don't know any better either.
  • + 2
 Yes true! But just as we spoke above, there are few factors that play role in specific riding characteristic - like stability. The thing is that not everyone is after the stability. Longer the wheelbase more stable the bikes is but it is easier to manouver a short bike in the air, like Spec SX is great if you are after tricks. Super fast bikes like enduro racing and DH rigs definitely are after stability, they combine low BB height, long TT and slack head angle(long trail Wink ). But slower bikes like hardtails, 5" trail bikes can't go that fast as they have too little suspension, then they go for compromises like giving up stiffness for the sake of cutting the weight. Lower the BB drop, harder it is to pick the front wheel up. That's why for not so tall people, 29ers suck at flying or pumping: combination of long CS and considerable BB drop. 29ers will never ever be film stars.

I feel that 650B will be the future of "ticking clock driven" mountain bikes for competitive people, and along with 29ers they will be the best choice of beginners. It will be interesting to see what comes out of 650b vs 29" in Enduro. But 26ers will redefine themselves as "the shit" as "bike handling connesseurs" bikes, kind of gokarts of MTB. At least that's the future I'd like to push forward with my (hopefuly) future designs. Not everyone has trails on which you can use 26ers potential to jump around. We'll observe a massive yet not complete die out among die-hard 26" riders, in the same way that dies the spirit of riding among people getting into a big change in life, be it finishing school and getting a job, or getting kids. I imagine them to be a niche product in >500$ segment by 2020.

Ok sorry, got carried away, that discussion gave me more than everything all together here since few years.Thanks!
  • + 1
 Not to go on and on, but BBdrop does more than just stability. It provides a sense of "stuck to the ground- tracking/traction' for lack of a better term. This feeling occurs in both stable and nimble situations. The downside is ground clearance. I don't know if there is a drawback to going too low, as it isn't possible with crank driven bikes.
  • + 1
 You can go too low, very easily, depends where the bike will be ridden. Where I live: no way - too much cranking over large rocks. In my hometown in Poland I could go a full 1cm lower as you climb on fire roads and ride with cranks leveled for the "gnarly" bits. Things are also waaay faster in big mountains, and require stability and feedback, while on rocky hills, you need something to manouver around rocks, whoch are too big even for a 29er to plow through, on flat and uphill sections (That's why I am selling it). That's what I like with the idea of "local" stuff and custom bike building, you get a chance to get the right stuff for the job. Large companies selling thousands must cater all terrains and people's sizes, so we end up with compromises. I hate suspension design patents, as there are very few reasonable ways to connect the rear wheel with the front triangle.
  • + 12
 Definitely cool to see manufacturers exploring variability in fork geometry, and not just frame geometry.
  • + 8
 Interesting read. If you need anyone to check your grammar and punctuation, just get in touch;-)
  • + 2
 Yeah, seriously. Every new article I read on Pinkbike seems to need more editorial review than the previous one...
  • + 5
 "Most bike manufacturers design around industry standards and creating change within that world is slow and difficult."
Come on ! This industry has no standards... In the last 10 years we got 2 new wheel sizes, two new handlebar diameters, a bunch of BB systems, 2 X 10 , 1 X 11, 142 rear axle size, 135mm offset rear (pugsley), giant OD standard, 2 chain guide standards...
Slow and difficult to change ?
  • + 3
 He means standards *within* companies. His point is that the majority of bike companies use OEM forks, so they design around Fox specs for example. Because Fox is getting input from a boat load of customers (private and corporate), they have to weigh the data, and then slowly introduce changes overtime so not to piss everyone off. This is limiting to designers, as they have to design around what is avaialable, not what they can create. Murray's point is that Cannondale makes their own forks, so they can do whatever they want to optimize their bikes geo's.
  • + 0
 This Bliss feller has a point, despite how repugnant the idea of cannondale being innovative is. I'll stick to my Pivots.
  • + 7
 Do you guys proofread this stuff before putting it up?
  • + 2
 yeah, stuff like "45-50mmmm rake"
  • + 2
 " What that does is allows us to kick the head angle back to a relatively slack, 69 degrees, which if you kept that with a 45-50mmmm rake on a 29er, you would have the most sluggish handling bike in the world."

I think you are a bit confused here and if not you're definitely overstating the effect of trail. A Fox 34 29" fors run 51mm offset, are you saying all the sub 69 degree bikes on the market running this fork are sluggish?
  • + 1
 51mm offset isn't 51mm trail. You need to do the trigonometry to get the trail number, which depends on offset, HTA, A to C distance, as well as outside tire diameter.
  • + 1
 Yep I get that. Where are you reading 51mm trail?
  • + 1
 Actually, the Cannondale spokeperson's comment is reasonable. It is jarring to hear that even as fork offsets have increased, they haven't increased nearly enough. Also, there is this wrongheaded supposition about that Gary Fisher has resolved all of the issues around fork offset with the so called "G2 geometry" - 46mm for 26in and 51mm for 29in. Trouble is that "G2" is not consistent, not if the idea was to allow 29ers to be as slack as their 26in cousins. A 51mm offset on a 29er fork results in the same mechanical trail - the crucial parameter for steering response - as a 39mm offset on a 26in fork. But if the G2 philosophy is really about slackening the head angle and compensating with increased offset, i.e. to give a similar mechanical trail and thus steering feel, then 29ers should have offsets in the 58mm+ range. An offset less than that means that a 29er must always have a steeper steering angle than a 26in bike (with 46mm offset) for the steering to feel similarly responsive. Please don't take my word for it, check it in one of the web bicycle geometry calculators. Use "bicycle trail calculator" in a search engine.

It seems to me that Cannondale is just continuing what Gary Fisher started. They are to be commended for picking up this dropped baton. Also, do not be surprised if in two years time we hear that the right offset for a 27.5in bike is closer to what we are currently being advised is appropriate for 29ers! My crystal ball tells me offsets in future will be in the following ranges: 26in - 46 - 48mm, 27.5 - 51 - 53mm, 29in - 58 - 60mm. Head angles will be slacker by about 1 degree. That's my guess anyway.
  • + 2
 I'd totally thought the index-tabs for setting a front thru-axle was the start, a cam-feature to bring in and out fork's trail. That was... 5 years ago!!! Proper addition to the tuning-factor of a bike however. Adjustable Headsets are a terrible product... let the neg-props begin!!!
  • + 6
 That was extremely long leaflet.
  • + 5
 I knew this was going to happen, sell your slack angle frames and buy new steeper ones with a short rake fork!
  • + 2
 No no no. Go slacker with more offset ;-)
Steep forks are dangerous. We have shorter stays to help quicken up the steering.
  • + 1
 This topic will be obssessed over and redesigned til the end of time. Always looking for that perfect setup that can handle high/low speed and all in btween. I think alot of it is personal prefference, riding skillz and type of terrain. My phylosophy is spending more time on same bike allows you to learn how to handle every diff situation. Some riders find a flaw then switch frames, forks go crazy. Sometimes its just you, something your not doing right in bike handling. This is a good topic and much thought needs to go into it for every rider. Even bmx racers think about this. Tire height and suspension setup can also affect the overall handling and should be taken into account when deciding fork rake-head angles.
  • + 1
 Nice geometry talk. Those new Mondraker with bigger top tube and zero stem... intresting to think about having diferent drop out length to change the lower of the fork to fine tune the bike geometry. Not only tweeking with adjustable aheadsets and shock frame ajustments.
  • + 1
 i had a cannon dale Jekyll in shop and it looks so strange and theirs so much stress on the hub because of that fork design i would never ride. its just to weird for me i like my traditional fork suspension. but then its all up to the rider
  • + 1
 All well and good designing a bike around a customised fork that has a non standard rake/trail - but nightmare if you want to replace/upgrade the fork (although if you do buy the pictured Cannondale you have non standard rear shock, front hub, headset etc. already. so what's another nightmare).

Catch 22, I suppose - stick with the standards and nothing changes, or innovate and to hell with standards.
  • + 3
 Those lefty forks make me cringe.. they look so weak! I know they aren't but still..
  • + 2
 I will be burn alive, but I don't like the concept of Lefty for AM. Don't know why, sorry guys. Anyway it's interesting article.
  • + 1
 Agree, a lefty seams like it is not balancing the bike which is kind of the point of geo talk, it all comes down to balance. I might tip over turning left.
  • + 5
 Careful not to tip over turning right with your entire drivetrain on the right side of your bike. You should probably balance it out with some extra weight on the left side just to be safe.
  • + 2
 Uh oh there is shifter on the right of my dh bike but there is no shifter on the left... Need balance :O
  • + 3
 Cannondale should make an 8" travel lefty and a righty and combine them into one bad ass inverted downhill fork.
  • + 1
 Thanks G-Sport. Nice supplemental reading.
  • + 2
 So is which is preferable - more trail, less trail.. or does it depend on head angle?
  • + 1
 Not too much, not too little, but just right!
  • + 2
 You need the right amount for the intended purpose of the bike, the components used, and intended ride.
  • + 1
 right, but what IS the right amount for each purpose?
  • + 1
 That's the problem Jerry - it's still being worked out
  • + 1
 The right amound depends on all of the other variables. The correct trail is one of many variables that work together with HTA, STA, BBdrop, CS length, TTlength, front center etc. There is no "this is the right number." All of these design parameters must work in concert. When things get skewed to an extreme, such as a trials bike, or a DH bike, neutral handling does not apply. The designs are for a specific purpose, and are lousy in other areas. Marketing has overemphasized HTA as the defining feature on frame handling, as well as high emphasis on CS length. How the bike is weighted is a design parameter as well. A touring bike, with racks and paniers, or a tandem has different frame loading (I don't build those- no experience with the design parameters and would likely screw it up royally) and therefore different trail numbers (longer IIRC.) With an enduro bike, 650b gives a better BB drop number than a 26" frame. 29ers would be great on longer travel bikes, but they take up too much room at the BB SS junction, so compromizes have to be made. 26" wheels have horrible BB drop numbers, resulting in the need o slacken the front end excessively. More BB drop generally equals better stability, and cornering traction. Pedal strikes are the problem though.
  • + 1
 Couldn't give a fuck about the details, just make it ride nice, job jobbed.
  • + 1
 i hate those forks! you look at the second picture and start thinking someones hacked off half your fork!
  • + 1
 "How do you apply this to your bikes than?" DOES NOBODY APPRECIATE PROPER GRAMMAR?!?!? WTF PINKBIKE.
  • + 2
 Gonna need to re-read that.
  • + 1
 Holy I would not ride forks like that.. Damn.
  • + 4
 There's a great video that illustrates how stiff they are - impressive stuff.

www.youtube.com/watch?feature=player_detailpage&v=_WlRqcAQr2w
  • + 1
 Trek has been doing this for a long time.
  • + 1
 Does Pinkbike proof read their articles...
  • + 1
 F$%#k this I will just go out and ride my bike.
  • + 2
 Zzzzzzzzzzzzzzzz
  • + 1
 #learnedMoreInTheComments
  • + 1
 Am i the only person who rides high rake?
  • - 2
 no matter how much will they put into them, over complicated over engineered crap will never pass. C'mon, pull shock and a lefty, on a bike that needs to sustain abuse as a DH bike and stay in one peace?

No way Jose!
  • + 0
 i was like, "this could be interesting" then i was like, "this is a fancy advertisement"
  • + 2
 I never knew they had "valley girls" downunder!
  • + 1
 Like lol
  • + 1
 g2 ! trek! they explain better
  • + 1
 Use the force!
  • + 1
 i would like to try it
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