Aaron Gwin's Modified Specialized Demo
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The 2015 race season is beginning to gather steam, which means that many of the top pros are spread out around the world to race national and local rounds in order to put in some runs against the clock. Some also use these races to evaluate new components or changes to their race bikes that they'd have to otherwise test in private - as anyone who's competed at a high level knows, you're going to take chances in a race run that you might not otherwise take during regular testing.
That fact makes these pre-season races, especially the hotly contested Fontana rounds, an ideal place to test anything that could give a racer an advantage when it really counts. That's exactly what Specialized's Aaron Gwin was doing at the last Fontana stop when his Demo race bike was spotted with a rather unique and definitely not production rocker link. A little digging showed that Troy Brosnan has also been using the prototype link, and he even won the Aussie Nationals with it on his bike. Reaching out to Specialized's Senior Engineer Jason Chamberlain, who actually designed the new link, revealed that there's quite a bit going on with it, and that both Brosnan and Gwin are fans of the changes.
How is it Different?
The production S-Works Demo, as well as the bike the team has been racing on up until recently, is fitted with an impressive carbon fiber link that's mostly hollow expect for some internal carbon ribs and a small amount of foam, and it's said to be 240 grams lighter than the aluminum version on the less expensive models. The rocker link pictured here on Gwin's bike, as well as the one Troy has been using, is actually a CNC'd aluminum unit that has been machined right in Specialized's Morgan Hill headquarters, and Chamberlain explained to me that it's just a few grams heavier than the S-Works carbon fiber link.
And speaking of weight, the prototype link rotates on smaller sealed bearings than what you'll find on the production bike, which helps to save a handful more grams. There's always a tradeoff, though, and the flip-side here is that the smaller diameter bearings aren't going to hold up as well compared to what's used on the bikes that the average consumer can buy, but that's not a concern to the Specialized Word Cup racers.
The production S-Works Demo, as well as the bike the team has been racing on up until recently, is fitted with an impressive carbon fiber link that's mostly hollow expect for some internal carbon ribs and a small amount of foam, and it's said to be 240 grams lighter than the aluminum version on the less expensive models. The rocker link pictured here on Gwin's bike, as well as the one Troy has been using, is actually a CNC'd aluminum unit that has been machined right in Specialized's Morgan Hill headquarters, and Chamberlain explained to me that it's just a few grams heavier than the S-Works carbon fiber link.
And speaking of weight, the prototype link rotates on smaller sealed bearings than what you'll find on the production bike, which helps to save a handful more grams. There's always a tradeoff, though, and the flip-side here is that the smaller diameter bearings aren't going to hold up as well compared to what's used on the bikes that the average consumer can buy, but that's not a concern to the Specialized Word Cup racers.
The rocker link on Gwin's Demo is a prototype that won't likely ever see production.
Gwin's FOX RAD DH shock - which looks like it came off of a production line, by the way - is the same length as stock, as is the RockShox Vivid that Troy uses, but the altered mounting locations mean that a short extension has to be used at the bottom end to compensate for the changes and preserve the bike's geometry.
The other big difference is the built-in adjustability the team now has compared to the non-adjustable shock mounting on the S-Works carbon link. Chamberlain actually employed the eccentric flip-flop chip from the old Demo, making for three different geometry possibilities, although he also said that both Gwin and Troy have stuck with the stock settings for now. The other two options give them a range of +/- 6mm of bottom bracket height, and less then +/- half of a degree of head angle adjustment if they choose to tinker with them.
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 Brosnan racing in Australia with the prototype rocker link on his bike. Photo by Kane Naaraat |
What Does it Do?
Specialized is not machining the prototype rocker link for the team to have more geometry adjustments, but rather for added bottom out control. ''The top ten pros do things with bikes that no one else in the world does,'' Chamberlain explained ''And one thing we have found is that they generally need and like more progression than the rest of the world, so this link has more progression built in. That means the shock does not have to handle bottoming with compression damping as much.'' The revised rocker link also provides increased sensitivity at the beginning of the stroke and also allows the bike to ride higher in the travel, all things that Gwin and Troy have really liked about the switch. ''Troy and Aaron have both been riding it for some time now and they like it better. They're faster on it, according to our testing, and more confident, which is the most important thing,'' he says of the World Cup team's feedback so far.
I know what you're thinking: is your nearly brand new Demo already getting updated? Very doubtful. ''Your average consumer wouldn't be able to tell the difference,'' Chamberlain replied when I asked him if production bikes will eventually employ a forged version of the CNC'd prototype link. ''We design for the ninety-nine percent, and then fine tune it for our pros.''
Main image by Scott McClain
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I would expect Troy to get a win or two this year, the Demo seems to work better for him despite the unstable ride from the too-low concentric pivot that produces instability and traction issues.
Neg prop me all you want, make alterior excuses for Gwin's shortcomings, or go full-blown-WakiBabble on me; The truth hurts. This suspension design is inferior, and Gwin moving to Specialized was the worst move any racer has ever made in the history of mountainbiking. Had he stayed at Trek he would likely be the all time leader in World Cup wins by now.
It's a multilink design, how can you make any assumptions about what it's doing by just looking at the position of 1 pivot?
Aside from riding one you can even see in slow motion film how poorly their demo (the last few versions) reacts to the ground, compared to the other high end bikes out there. They made a huge jump in the right direction when they ditched the double chain stay design. What a disgusting and unnecessary design in terms of un-sprung weight that was. However Theres been some issue with Spec's management of their WC DH team and management in general. After this last season Eric Carter was able to turn it around for the better. Although they werent the best team out there, he was able to give the riders some stability and comradery too, and improve on past year team results. So what does Spec. do? they can him because he doesn't fit the corporate model with power point presentations and numbers that Spec's NEW manager wants to see. Of course this also plays into the mental game along with not be confident in your bike. Im guessing Gwin will stay put for a while. Im sure the money is great. Hopefully Spec can figure out something that works for them.
www.pinkbike.com/news/interview-eric-carters-magic-season.html
Are you high?
Also can I ask where you got your degree in armchair engineering from? I'm studying to be a real engineer now, but I'd like to get my armchair degree, just so I can flex on pinkbike.
That said I think they Specialised look on paper have a pretty good setup potentially, interesting like you they are tweaking it allot, yet SC, even Nukeproof for example seem to nail it first chop, fer sure they are always tweaking too, Ive always thought the Demo was a good bike and for some riders and works well, I rode a few a and while good I never could understand why some would tell me Id sell my current rig afterward, never happened, but everyones different and different things work for different folks.
No doubt in my mind Gwin and Trek were something special, ancient history now, what could have been will never know, lost on most people as they are branded, dont cross that, flame on!
Still I wish Gwin and Troy all the best for this season, I think it will be even more competitive this year, George Branigan break through imo, Ratty back, Troy for sure will be wanting more, and then Sam Hill hes gonna want that title this season, hoping good things for Brook and esp SammyB too, Norco could be just what he needs, everyting else is they're. back on point though, the RAD shock looks interesting, Fox comeback bigger than Gwin and Specialised me thinks in 2015, finally listening to the market and pressure from Sram success and others, think it will be a gold hear for Fox with new coil shock 25mm incre springs, new DH air shock yadda yadda yadda, Go Time!.
..he got 4th overall
www.uci.ch/mountain-bike/ranking
and was beaten by troy by over 200 points. so the demo works but not for gwin. it was more then impressive to see what he can do on a trek. remember val di sole 2013 where he was switching from medium to large - that is not something you do when you feel confident on a bike.
don´t get me wrong - don´t won´t to troll around and i really have great respect for every rider and gwin pushed the whole dh racing to a new level, but the demo simply doesn´t work for him at the moment and i agree that the psycological part of racing is for sure a big thing now (...after having two quite medium seasons speaking in gwin´s standards pre-specialized)
The competition didn't step it up as much as Gwin slowed down. The obvious proof of this is to look at his times on tracks such as VdS, where he was much slower his first year with Specialized, and the winner didn't come close to Gwin's dominant time the year before. Also, his only World Cup win with Specialized was on an Enduro, he has yet to win one on a Demo. Pretty stunning when you consider his success on a Session. But he is obviously still fast, and I wish him the best this year. But if Specialized really wanted to help him out, they would lengthen his chainstays by at least 10mm and raise the main pivot a couple inches.
@ZeGermans The main pivot largely controls the axle path on the Demo, which is the most upward and inward of any bike in the history of DH. I made this scale drawing awhile back to show it:
m.pinkbike.com/u/protour/album/2015-Demo-axle-path-Up-In-WTF
If having the weight lower in the frame is so important and the main pivot location doesn't matter(it does), then why not lower it even further, as I have jokingly speculated Specialized might do in 2016:
m.pinkbike.com/u/protour/album/Potential-2016-Demo
See anything problematic with that main pivot location, other than the back wheel hitting the frame?
Gwin was 2nd.
en.m.wikipedia.org/wiki/2014_UCI_Mountain_Bike_World_Cup
Just saying...
And if (I'm hoping when) Gwin does return to the top step of the podium on board the new Demo, you will still say he won "despite" being on a Demo. Which is utter nonsense. Any bike that is capable of winning a UCI Elite DH race is a machine that deserves respect. There is no room for "despite a bad design" on the top step of the podium- the competition is too fierce to win on anything but well refined design.
So I ask: Will it ever stop? I always stand in defence of the persecuted. Hereby I come forward and tear my clothes before you, I stand proud and naked, and I say this to you, free People of Pinkbike:
I AM SPECIALIZED!
Personally I think Gwin and Trek was a combo that was kind of like Hill and Iron Horse, it had some magic that just worked. Albeit Gwin's style might have suited the Session better for what ever reason. The Demo definietly have some peculiarities in how it rides, which imo dont go well with a monster trucking moto style. Gwin and Brosnan imo have very different riding styles. Gwins run in VdS when he smoked the field was everything but "smooth" he just held on and let go of the brakes.
So its not so much that the Demo cant go fast, it just caters to certain style of riding.
A small anecdotal evidence, Hill came back fast after he left Specialized for Nukeproof.............why is anyones guess. But he has also always just been a let go of the brakes and smash it kind of rider.
Face the facts Protour... even dominate champs often fall very fast and far, Jeremy McGrath went 15/16 race wins in 96 to come in dead last round one in 97 and only slowly got back on pace.
He started on a medium demo, did mediocre
He changed to a large right before a race, they didn't have one and had to get one from a local bike shop, he did mediocre
He got a custom rear end to lengthen the chainstays (who knows what it did to the compression curve on his custom tuned fox) he did mediocre
switches to a prototype 650b, he did mediocre
He starts next season on an enduro, he wins
Switches back to the 650b demo, does ok
forced onto an entirely new bike mid season by Spec, does worse
Now hes on a custom link that cost more to machine and heat treat than Eric Carters salary last year.
AG has been working out the kinks. when he first started with Trek, he wasn't dominating off the start.
I bought a demo in 2013 and I didn't get along with that bike, sold it to a friend of mine and he's having a good time on it. I am saying this because I do not hate specialized bikes, but I hate their marketing strategy. They have the know how to sell fur to sheep. They took Gwin after he dominated two season of wc on a Trek and put it on a demo and used this good marketing title "see why Gwin is the fastest man in downhill" he was the fastest on trek not on spesh... ironic, it kinda backfired.
If Specialized went with that design purely for weight reasons and missed the kinematics part, that would be a huge blunder for a company of their size and engineering proves.
A quick troll: but the Devinci also has a concentric BB rocker!
hamncheez with the closeness of the chainstay link and the axle, the two paths will be quite similar to each other. The upper link should rotate the wheel link backwards a bit and due to the geometry should move the axle path a bit more rearwards (compared to the pivot path), but not enough for the bike to give some more rearwardness.
Does it even have any reawardness in the axle path? How high is the BB, around the wheelbase line?
And yes, the split pivot also has a concentric rear axle pivot, which in effect makes it a single pivot, when it comes to axle path and pedaling. But not when it comes to braking performance!
I knew there'd be at least someone that would get caught up in that detail, quick troll successful then.
www.youtube.com/watch?v=i2gZ0aulUt0
It's a modified version of horst link with an axle path similar to that of a single pivot. Just like a session, or a wilson, or a gambler.
@samsq - (not criticizing you by an ounce, on the opposite happy to see this) as informative as this video can be, it is exactly how I imagine many people judge mountain bikes: bike and terrain, that's it, where as world cup rider weighing anywhere between 60 and 85kg has a dramatic influence on what suspension does, he makes half of those bumps there to act with greater force than depicted and he will barely smidge half of the obstacles, where as every single aspect of suspension, SAG, rebound, compression will be adjusted to his preference and have even different outcome. SLippery or dry conditions, will provide even more different forces on the bike, not only by themselves, but also due to riders input who applies different technique depending on conditions.
But the way of a fool is to take all that complexity and narrow it down to idiotic comparisons between chain stay length, leverage ratio, head angle, spring medium whatever comes up. Cross out one bike, one rider, all things that make humans' life, all the things that make human body and nervous system and put it down to fkng 1cm of difference on linkage bar or pivot location, and that is because some people are so stupid they cannot see how fkng dumb they are. Bike plays a role sure, but even most pros don't know in what way, and if common sense is not enough I have that from the mouth of Steve Jones. and let me play this card that he may not be the God of MTB but his word, through his riding skill and what he has seen in his journalist career is worth 1000 times more than all trolls together.
You've just gone in the other end of the extreme spectrum.
And no, singlepivots are NOT useless. But they do have limitations when it comes to being influenced by braking and when it comes to antisquat properties. With a virtual pivot point, that is moving around through the travel, you have much more freedom to play around with the design and achieve what you want.
Ofcourse all of that can backfire badly on you.
Also, if two bikes have THE SAME axle path, regardless of the underlying suspension system, they will ride the same. But two singlepivot frames can have a wildly different suspension path, much more so than a single pivot a virtual pivoted bike, depending on the design.
In the end the suspension system is just a tool for the engineer to achieve what he wants and the marketers to slap a bunch of buzzwords on the bike to make it sell better (Transition's COCK and BALLS comes to mind here).
Neither Gee nor Minnar ever had a dominant season, at least not in comparison to the two years Gwin had with Trek Not even Nico or Hill ever had a World Cup season as dominant as either of the seasons Gwin had on a Session. So your point is mute.
Primoz: "Does it (the Demo) even have any reawardness in the axle path?
No, especially when you consider the sag from rider weight which lowers the BB even more.
Waki: "Every argument with him left me feeling angry and displaced."
Not surprising considering you rarely have facts to back your ideas with and instead rely on predictable eccentric sarcasm and meaningless personal insults. Know your strengths and stick to them Waki; your's are in creating science fiction mtb drawings.
He started on a medium demo, did mediocre. He changed to a large right before a race, they didn't have one and had to get one from a local bike shop, he did mediocre. He got a custom rear end to lengthen the chainstays (who knows what it did to the compression curve on his custom tuned fox) he did mediocre, switches to a prototype 650b, he did mediocre.
He starts next season on an enduro, he wins, Switches back to the 650b demo, does ok, forced onto an entirely new bike mid season by Spec, does worse.
Thanks for the accurate historical analysis hamncheez. The people who claim it wasn't the bike that slowed him down are essentially disagreeing with Gwin himself. If it wasn't the bike he wouldn't have been desperately trying so many changes, especially during his first rough season with Specialized. It's interesting to watch the denial and the excuses people make for Gwin's drastic downfall with Specialized. Even though I predicted it in my first post here, people still trot out the same old disingenuous excuses and dishonest arguments, It's as if they simply can't believe that Specialized would produce a bike that would cause a rider to go slower, when all the evidence obviously points right to that fact.
Waki: "I AM SPECIALIZED!"
You two at least have a couple things in common: overhyped and a bad ride for many. But you lack the lawyers and the lawsuits.
Too bad it comes down to the rider, not the bike. When Gwin loses, unless it's by a really narrow margin it's his fault, not the bike's. And when he wins, it is his victory, not the bike's.
Edit: come to think of it, it's a little early to criticize the new demo considering it was released to the general public before the 2015 season even started...
If for some reason you are unable to contact any source of reference for your assumptions (these are not even theories according to academic terminology), from any company in the world please tell me; I shall fix you any contact, any rider, any engineer, any journalist. I give you an opportunity for some quality journalism but I am not going to do it for you because I argue with you for the sole purpose of entertainment, while you try to win an argument, which nobody cares about. Nobody wants to win an argument with you, that's my assumption off course.
And science... do you even have a Master degree?
The proof in this is the nem Commencal Supreme, which is a high pivot with an idler. Or Ghost's DH bike. Or Bull's. Or a Canfield Jedi, same story, they all have idlers. Or any Nicolai gearbox bike, which have their pivots on top of the gearbox in most cases, so yeah, higher up, giving a more reaward travel path.
The extreme case in this? Zerode.
Now, the logical question would be, why don't all bikes have really high pivots? And the answer is really, really, stupidly even, simple. Pedal kickback. The higher the pivot (or instant centre of rotation) is, the mor echain stretch you have (and therefore also more antisquat). If you don't want that, you need an idler. Or just something, to move the chain line (the line between the sprockets, not the left-to-right position concerning front rings) higher up. Like a gearbox right under the seat (Zerode again).
It's interesting that Protour is labeled a troll. Sure, his manners COULD be better, his execution of his views and points as well, but dammit, the guy does have a point. Though i'm beginning to wonder, maybe you must be an engineer to understand him?
stickman so he likes the new bike better. He's still not as dominant or as fast (supposedly), as he was on Trek.
The new demo doesn't have a dramatically forward axle path. Most horst link designs essentially have a mild virtual pivot point. Protours dumb drawing has his arc following the horst link, not the axle. There is an acute angle on the link on the chainstay, and it pivots obtusely, lengthening the chainstay. As it cycles through its travel, there is chain growth. I bet its somewhat comparable to the old demo, Trek session, and other,more traditional suspension designs.
So for that fact alone the big S will always get a big thumbs down from me.
Was a fun bike atleast when not in the stand!
@stickman5000 i was aiming at the point that his times from a few years back haven't been equaled yet. I haven't checked those facts, i'm just putting them up for consideration. The rider is a big, BIG part, even more so in cycling. But you can't say the bike is not important at all. That's just impossible. It has to have an effect. I'm not saying the Demo is the sole reason for Gwin's worse performance, i'd say it's mostly him, he did change every single piece of gear he has had in Trek days, apart the suspension manufacturer. That should shake a guy up a bit, adding to that the legal battles and all. And it's then easy to get into a funky mood and not deliver results wise for 2 years.
@hamncheez i've said that the pivot and axle paths are not drastically dissimilar, though indeed they are not equal. It's simple, a low main pivot will pull the chainstays and the rear pivot inwards instead of outwards. Only the pivot-to-rear-axle distance can then make the path rearward, if the whole wheel link rotates counter-clockwise. But that's hard to achieve and would give TONS of brake jack.
Yeah, not many (if any at all) high pivot bikes have won the WC, but i think there's a different reason. Most of the winners have had really good support from the manufacturers, so we're talking about established players in both regards. And established players (brands) tend no to do something extreme, since people don't really like these extreme things. Therefore none of the big players has made a high pivot bike. Or any of the bigger (or larger) players with a high pivot bike hasn't had a world class rider yet.
Observe this animation of the 2015 demo.
www.youtube.com/watch?v=i2gZ0aulUt0
Notice how the axle path is mostly vertical. Also notice how the seatstays barely rotate with this design (ie: no brake jack). You can quite clearly see that as the chainstays rotate clockwise, the seatstays stay the same.
How is a rearward axle path extreme? It's been done hundreds of times. If it were the superior design, it would be completely illogical for multi-million dollar companies like trek and specialized to not have built a bike with it. However, they obviously haven't.
What a rearward axle path is good for:
-Plowing through rock gardens
-Casing jumps/drops
Problems with a rearward axle:
-Requires an idler pulley
-Corners poorly due to lengthening chainstays
-Lack of pop off of jumps due to lengthening chainstays
The cornering point is the most important, as that is where people lose speed in races. Not rock gardens. At race speed a few bumps isn't gonna slow any rider down, it's the corners that get them. That right there is why rearward axle paths are uncommon.
www.mtb-news.de/news/2013/04/08/nachgefragt-mit-aaron-gwin-zu-gast-bei-specialized
(Yes it's in German)
There is some company that provides all sorts of data on many suspension designs, I don´t remember the name, they are maniacal on graphs and curves. They made a bike with what they see as the best suspension system out there... and it looks like crap. The bike looks like their dea for a business would go: Step 1. Get funds, Step 2. Design suspension, Step 3.? Step 4.Profit
"Neg prop me all you want, make alterior excuses for Gwin's shortcomings, or go full-blown-WakiBabble on me; The truth hurts. This suspension design is inferior, and Gwin moving to Specialized was the worst move any racer has ever made in the history of mountainbiking. Had he stayed at Trek he would likely be the all time leader in World Cup wins by now."
1.bp.blogspot.com/-sgPEPGusHIM/Ti0-tWnYk1I/AAAAAAAAFTE/zg7MksB_V74/s400/Trek%2BSession%2B99%2BCarbon%2B2012_LevRatio.gif
leverage of gwins trek session 2012 (quiet linear leverage, low brake squat (approx. 50%), low kickback, medium pedal efficiency
3.bp.blogspot.com/_XzSTrx00Xx4/TTModrFz5UI/AAAAAAAAEPE/d7TlWXlNans/s400/Specialized%2BDemo%2B8%2B2011_LevRatio.jpg
leverage of specialized demo 2011 (identical to 2013-14 sworks cinematics), low brake squat (approx. 30%), almost no kickback, low pedal efficiency
Pls. argue with facts when talking about suspension design. Both designs are quiet similar in suspension characteristics, the difference in both bikes is based on the geometry, thus chainstay length.
Nobody can tell how he would perform if he was still riding Trek, but there are much more parameters than the bike. Simply put the blame on a bike is quiet biased, especially without background information on suspension design without any prove by facts but your personal opinion.
As for extremenes and reaward paths, i was talking about extreme rearwardness in itself, not that rearwardness is already extreme. It's not. Most bikes have at least a slightly rearward path, at least in the beginning. That's how it's done, a bike with a low main pivot location, if it's a single pivot, will pedal like crap. Raise the pivot, you get antisquat and you also get some rearwardness. Same goes for virtual pivots.
As for why the big companies haven't done it, they make bikes to sell, to look good, not to work good in the first point. An ugly design won't sell, just like waki said. That's how it goes on the open market.
And a reaward path does not require an idler pulley, like the vast majority of full suspension bikes prove. It's just the extreme ones that need it. And BTW, all bikes have a lengthening chainstay design, apart from concentric BB pivot designs. And pop off can be fixed in a different way (shorter chainstays).
What matters when you talk about chainstay length is the horizontal distance from the bb to the axle, not the actual distance. This is because less horizontal length means you can get you weight farther behind the rear axle, giving you more leverage when you pulls the bars up, and a shorter turning radius.
Um... Why would you want your weight over or rather behind the rear axle and pull up on the bars, when you are cornering? You're supposed to be centred over the bike, loading both wheels about the same, giving both of them the same amount of traction. The only problem with an extremely rearward travel path in this regard is that the 'bike centre' is moving backwards, since both the front and the rear wheel are moving backwards. With a more conventional design, the wheels are coming closer, leaving the bike centre more or less the same, i.e. the front centre to rear centre ratio doesn't change much, so you don't need to move your weight around depending on the amount of suspension travel.
You're right, that was badly worded. The reason shorter chainstays give you a better turning radius is because the bike is shorter. Not only that, but (this is hard to explain without drawing something, so bear with me) with shorter chainstays you can slide around corners better. This is because your feet are closer to the rear wheel, so you have more leverage to push the bike side to side. With a lengthening chainstay design, as you apply pressure to slide the suspension compresses, lengthening the stays, and making the corner more difficult. This does not apply to perfectly groomed bike park berms, but since actual race courses don't have too many of those, it can be a problem.
The whole 'weight behind the rear axle' thing specifically refers to how easy it is to pull front wheel off the ground. IE, popping off of jumps, manuals, etc...
@Primoz the new demo has a rearward axle path; I bet is comparable to the older demo and the trek session.
As soon as I saw it I started criticizing the concentric BB main pivot, and I have no intentions of letting up so long as nobody can counter my criticism of its clear lack of stability, the compromise in traction it creates, and the momentum killing imbalance of the front and rear suspension axle paths.
When the rear axle path is going in nearly the opposite path of the front, it radically shortens the wheelbase and makes an over-the-bars situation much more likely. When rebounding, the suspension is essentially an ejection contraption when compared to traditional design when you consider the arc of the upward and inward axle path when it is rebounding.
Also consider the effect the radically changing wheelbase has on the traction when both brakes are applied(most likely in steep terrain also). The tires are more likely to break loose because the wheelbase is changing so radically.
Lastly, consider the effect the near opposite directon of the front and rear axlepaths. The wheels are essentially fighting each other in tough terrain, which in addition to creating the problems described above, would also have a negative effect on the momentum of the bike.
That's funny that you say that. When I challenged Jason Chamberlain ( @jason-at-specialized ) to refute any of my serious assertions of the Demo design, his only response was that nobody had ever thought about it or noticed it. He never once attempted to counter any of the flaws in the design I described above with a technical explanation. Nobody else ever has either.
Considering it wasn't a win, that hardly convincing considering he won about 75% of the World Cup races he entered while on a Trek Session. Compared to his previous unprecedented dominance, mediocre is actually a fair description for his performance aboard a Demo.
I never made that assertion so maybe you are out of your mind? I have no doubt Gwin falsely convinced himself that he could go just as fast on a Demo, especially considering the considerable raise in salary he reportedly received by switching to Specialized.
It's a classic story, one that young Pinkbikers can learn from:
Girl has wonderful relationship with sorta nerdy not-so-rich guy from Wisconsin (Trek). He treats her like a queen, the sex is great, the communication is great, and she is the center of his world. The relationship is special. Then some good looking rich brat from California (Specialized) comes along and flashes his riches in a moment of weakness and steals her away.. Turns out he is a narcissistic jerk who treats her like crap, ignores her, looks at other women, and they have terrible chemistry.
When you have something magical, hang onto it at the cost of everything else in the short-term. Because I'm the long term you will be better off and happier. Now that Gwin isn't nearly the dominant racer he was with Trek, he won't be able to demand the salary he is getting from Specialized once his contract expires. In the long term he would have been better off staying with Trek. But Martin Whitely is sort of a nerd, right?
I actually do have the 'numbers', and they are pretty convincing:
www.rootsandrain.com/race688/2012-jun-3-uci-world-cup-2-val-di-sole/#helitem
www.rootsandrain.com/race1504/2013-jun-16-uci-world-cup-2-val-di-sole/#helitem
In 2013, the year that everybody supposedly 'caught up' to Gwin on a Specialized, nobody even comes close to matching Gwins time the previous year when he was on a Trek. And Gwin himself is considerable slower on a Demo, both in qualifying and finals. You are right that every rider has different times, but none are as dramatically slower as when Gwin switched to a Demo.
Uh, every graph you can find on Google images proves your assertion COMPLETELY WRONG. This was the axle path on the old Demo, BRFORE they lowered the main pivot by a gigantic 2":
img181.imageshack.us/img181/9642/yeti3032007axlepathnm9.jpg
Graph of shorter travel fsr axle path:
fcdn.mtbr.com/attachments/shocks-suspension/94657d1123183878-four-bar-vs-single-pivot-fsr-axle-path-jpg.jpg
So now, with the concentric BB, it is all upward and inward with the 2015 Demo axle path. No rear motion at all.
A horst link has very little effect on the axle path:
members.home.nl/vd.kraats/ligfiets/pa/pa41.html
Let's join our forces and raid! Let's unleash our fury on a road cycling or Miniature train forum! Our main weapons are distraction, persistence and irritation
NOBODY EXPECTS A TROLL RAID!!!
I honestly don't consider this fighting or even arguing, it is simply a comparison of ideas between different people with different opinions and assertions. I hardly take any of this personally, It's just guys typing into keyboards or smartphones about DH racing and suspension design. There are much more important things in the world, admittedly. But I don't find them as interesting.
But for some It's good to remind ourselves that we do all have one core thing in common: a love for mtb.
Also, that animation is not a really good shower of the axle path, imo. It's best if the frame is fixed for that
@Protour we were talking with WAKI and i kind of missed the point, the rear pivot on the wheel link is quite a lot lower on the new demo than is on the old one. So it's not THAT bad.
ep1.pinkbike.org/p5pb11289313/p5pb11289313.jpg
www.sicklines.com/news-images/2011_specialized_demo_8.jpg
It's about the same.
In actual fact, a reaward path will be more likely to induce an OTB, since less weight is over the front axle with the rear moving away from the rider CoG. With a more forward path, both the rear centre and the front centre decrease, if they do that at about the same rate (compared to one another, percentage wise), the balance should stay the same.
m.pinkbike.com/u/protour/album/2015-Demo-axle-path-Up-In-WTF
Do you know what a Horst link is and how it works? Do you even know what an axle path is? (Hint: it's the path of the axle, not the path of the chainstay pivot)
The bike was the main change, and he was obviously dissatisfied with it ot he wouldn't have been experimenting with different frame sizes and chainstays mid-season. If it wasn't his bike then what else was it? Changing to a TLD kit perhaps?
"Gwins time in 2012 is probably one of those one time everything just went perfect races"
Yeah I agree it probably was, and it was probably the greatest DH run in history, winning by 8 seconds in dry conditions. He and the bike were a perfect match, and I guarantee you he will never have a race like that on a Demo.
No bike in the history of DH has a more upward and inward axle path, and that is not a good thing when you think about how it correlates with the opposite direction axle path of the front wheel. Having two wheels going the opposite direction is what makes it so much more unstable, especially in steep terrain.
Also, What do you think happens when you are using your both brakes in rough terrain and the wheels are moving in opposite directions? Obviously it is going to cause issues with traction, because the wheelbase is changing so much. Probably wouldn't be as much of an issue on a short travel bike, but on a long travel bike with a slack head angle it is.
What's crazy is that Specializes created all these problems just so they could lower the center of gravity a little bit. This design won't last three test of time, give it a year or two, and the racers will be on a new prototype Demo mid-season after Specialized has sold out the remainder of their supply of this Demo. Especially if their racers are crashing more often. It will be interesting to watch but I wouldn't want to be the guinea pig on such an unstable design.
Hilarious, so this is why you are so butt hurt and want me to die? You are soooo sensitive, jeez. If you like the bike why worry about what others think? Do you need peer-approval from everybody for every choice you make in life, otherwise you turn into the insulting immature person you've obviously been on this thread? The one who had yet to actually yet to attempt to make a counter point to anything I've said? You write like a 10 year old with A.D.D.
Appropriate that you said fun as hell about your Demo, but definitely not fast as hell. Thanks for the laugh.
If by emotional you mean laughing at makripper, you are correct.
Gwin has become a much slower rider since he started riding a Demo. Why is this fact so difficult to accept when it's so obvious?
@stickman5000 says he thinks it's because Gwin is holding himself back... why in hell would a racer hold himself back? Possibly because he doesn't feel safe on the Demo, doesn't want to get injured? Like I said originally here, at this point his head is probably so screwed up in his head from all the negativity ever since he switched to Specialized he isn't gonna ever get it back. He's going to be a two year flash in the pan with a lot of question marks. Nice work Specialized, you absolutely killed the most successful racing career in the history of.the sport.
If Gwin is reading this(He has previously publicly acknowledged he reads some of my comments), I would encourage him to breech his contract with Specialized and move to another brand asap. It would be big news, but alot of fans would cheer it. He might pay a short term penalty, but he would be better in thelong run. He needs a fresh start, just like Sam Hill.
If he did breech his contract and leave Specialized before his contract expires, I doubt that Specialized would sue him for it. They wouldn't want the bad publicity, they already got too much of that when they tried to sue the war veteran in Canada and there was so much public backlash.
Revealing that you use the word 'manage' to describe Hill's underachieving time with Specialized. He didn't manage to win nearly as many races on a Demo as he did on an Iron Horse Sunday. He went from near-domination to mediocre, similar to The Fall of Gwin: though not quite as spectacular.
Troy hasn't raced on any other bike so there isn't any reference point. But I remember the time he slid out on the super-short chainstays Demo at World's, and its revealing that in his first race trying out the new unstable Demo he went over-the-bars.
youtu.be/bki2M-S8hwY
youtu.be/6uOaQPYEAlA
Gwin's winning percentage in World Cup races aboard a Specialized Demo: 0%
Butthurt Specialized Demo owners effectiveness at providing counterpoints to my assertions: 0%
I see a correlation.
You don't pay attention very well, do you?
Fact: Gwin has yet to win a World Cup races in a Specialized Demo.
As for Brosnan, one can't help but wonder how many more races he would have won last year on another brand, seeing how obviously the Demo has compromised Gwin's performance.
makripper (about 10 posts ago): "I never waste my time reading what you write anymore."
I think at this point it's fair to say you don't pay much attention to anything, including your own desperate, immature, and illogical statements.
I guess I forgot about Rppelato. He gave up racing DH on the Demo for the most part and resorted to using the Enduro instead. Still not successful in DH, he has now resorted to enduro racing. Pretty revealing. Based upon past history of other former Specialized racers, I predict he will switch brands, go back to DH racing, and become successful at it.
i'm all fine with your views, protour. it is just internet spit after all but i'd honestly wanna know why gwin and specialized that pulls this trigger for you? past experiences with both gwin and specialized? straight up no bs... just why. we all have reasons why we do things we do
everyone knows @Protour is useless.
Ps. Im laughing my ass off at you as I write this. Try and learn something new everyday. thanks for coming out kid
I'm not completely anti-Specialized, I actually publicly advocated their bib shorts to be the Pinkbike mtb product of the year last year and my advocacy for them got the top comment(143 + props).
m.pinkbike.com/news/pinkbike-awards-product-of-the-year-nominees.html
So there is clearly no strong bias from me against Specialized, despite what @WAKIdesigns insists at least one a week. He thinks of he repeats it enough it will become true and everyone will assume I'm anti-Specialized, but it's obviously not true.
But I am disappointed that their inferior DH bikes (both the old and new Demo) have killed all the momentum of the most dominant racer in the history of DH racing. I was enjoying Gwins dominance, and Specialized killed it. The old Demo obviously didn't work well for Gwin, and the new one is actually a worse design with its concentric BB pivot design that is unstable in steep terrain, compromises traction, snd kills momentum. All of these negative traits are the result of having axle paths of the front and rear wheel that are opposite of each other. The wheels are fighting each other, and the wheelbase is changing more radically than any bike in DH history. I challenge any of you to name a DH bike that has a more radically changing wheelbase in rough terrain. This is the part of the conversation where you all have nothing factual in response except insults and worn-out excuses.
Wrong again, surprise, surprise.... Nothing ever changes with you, and you never have any convincing responses. Anybody who reads all your replies on here and is honest will see that you are clearly the troll here. A very weak one at that.
Also have you actually put the Demo's axle path onto a computer program like Solidworks or a proper graph? You act like it's a straight up forward axlepath when in fact there is a good deal of chain-growth/anti-squat built in. Spesh engineers aren't stupid you know? They have actually screwed together a few decent bikes...
Check yourself before you wreck yourself, peace x
It is a straight up-and-in axle path, I'm not acting. I have analyzed it and taken the horst link into consideration. It actually causes the axle path to be more upward and inward, not less. There is no chain growth on the bike, when you sit on it and compress the suspension the chain only gets shorter.
makripper: "fullbug you won't get a reply to that"
makripper: "lol I said that so he would reply. I win"
Yawn
@Protour the BB pivot is lower. but so is the chainstay pivot. And the rocker pivots. The whole system has been moved lower down. Now, does that mean the axle path is the same? Hell no. Different positions on the floating link give different paths (pic lower down). But it still probably isn't all up and forward.
@makripper the Fury actually has a quite high pivot, even more so for a single pivot. The thing that rescues GT from having too much chain growth is their floating BB.
In all actuality, most bikes have at least some rearwardness in their path.
dl.dropboxusercontent.com/u/2426014/paths.PNG
These are the paths different points on the floating link line would have (if you made a triangle out of the link between the pivots A, B and the point, of which the path is shown). This is more or less directly applicable to bikes.
Primoz, the chainstay pivot is lower, but that makes no difference if the main pivot and the rocker are BOTH going upward and inward. How is the rear axle going to go outward(raerward)? Magic? Also consider rider sag, which essentially lowers the BB even more. This is all pretty obvious stuff when you look at the drawing, surprised you are resisting it.
But we can put this to rest. Luckily i have the personal version of Linkage and both bikes are in the library (the old Demo in it's 2012 incarnation though, not the latest 27" version).
dl.dropboxusercontent.com/u/2426014/2012.PNG
dl.dropboxusercontent.com/u/2426014/2015.PNG
I suppose the filenames are self explainatory.
scontent-sjc.xx.fbcdn.net/hphotos-xta1/t31.0-8/11146395_10153174137994323_7424563354647911672_o.jpg
it is so sad. armchair engineers everywhere. no idea of the true amount of relevant parameters, no idea of suspension, no idea of mechanics and physics, no idea of hydro dynamics, no idea of damper design (ports, shims, ...), no idea of lubrication, no idea of sports psychology .... no idea of anything - but talking sht like monkeys on cocain -.-
@Protour i respect your opinion - but i would like to see you riding, because it seems that you have no idea how the things you re discussing about really feel like. you re just discussing theoretical sht, and everyone with a decent technical knowledge knows that it's irrelevant in real life application. you say that the wheelbase of the demo changes to much when the suspension is compressed (it shortens soooo much), which leads to instability and more OTB moments (i hate this term, it's so armchairy). okay - so you mean there are less OTB moments, when your front-center shortens and your rear-center enlarges? if you take a look at a first lesson mechanics topic like this www.maschinenbau-wissen.de/bilder/skripte/mechanik/statik-balken-03.jpg you should realize, that in your prefered case the force on the front tire becomes higher ... which in fact (if it was as important as you think) would lead to more OTB moments (deeper into the front travel = steeper HA) and more inconsistent ride characteristics.
in the case of the demo, the forces stay more balanced - and that gives you a more controlled, more predictable ride.
especially with its short CS and long FC the demo is the last bike which gives you an excessive amount of OTB moments.
i try to keep it simple and use only inward and rearward ... inward is bad for square-edge hits because it works against the direction of movement. when a suspension with rearward axlepath expands its moving against the direction of movement - and the rearwheel hits the next obstacle with an higher velocity (speed) than the one of an inward-axlepath- suspension - which leads to higher "stopping"-forces ..... aaaahhhh confusion all over the place ... all suspension designs are shtty, the best thing are hardtails, because they have no fkng axle-paths with negativ side-effects!
truth is - it doesn't care ... everything has pros and cons. and no, the wheelpath or the location of the mainpivot is not the reason why a racer has a "not so good" season. hill won the '09 WC on a demo, got 5th at Maribor '10 with a time-costly crash only 5 sec off 1st, looked fkn fast in Fort William - crash - massive shoulder injury - then torn ACL - and so on - never fully recovered until last season. He has never been taking as high risks as before his injuries again, which you cann't blame him for.
Gwin started having problems with injuries at the end of the '12 season when he was on trek. he didn't seem to have fully recovered from all his injuries until this offseason - and suddenly he's ripping again.
as @WAKIdesigns said - the only thing i could blame specilized for is the bearing-quality - especially in the shock-yokes.
active suspension/grip under braking are way better than any other DH-bike i've ridden so far (w/o floating DM) - which in my opinion is more important on a proper DH track than pedalling efficiency. and the "bad" square edge performance (which i haven't felt till now) is compensated by the predictable geometry and stable yet lively ride-characteristics.
btw. it's not as if the session had that freaking much of rearward travel or high pivot ... think about it
ps: feeling quite armchairy now
ttps://dl.dropboxusercontent.com/u/2426014/2012.PNG
2015 Specialized Demo axle path:
dl.dropboxusercontent.com/u/2426014/2015.PNG
Thanks for posting these axle path graphs @Primoz. Pretty much is what I expected and confirms all of my ideas about the new Demo.
The new Demo design has over 10% more inward movement (35mm vs 31mm) than the old design because of the lower main pivot, and also has about 10% less rearward travel.
But just as significant is that the new Demo axle path starts going inward at about 42 mm (vs 49 for old design). This means that when the bike is in a sagged position there essentially no rearward axle movement. When you look at the angle of the axle path when it is near the end of the travel in the new Demo it is surprising how extremely inward it is, of course the wheels are going to be fighting each other and creating negative issues with the traction, momentum, and stability that I've described previously.
What you have here is a very radically changing wheelbase, more than any bike in the history of the sport, and nobody in their right mind is going to have advocate the benefits of that because there obviously are none.
Obviously the bike can be ridden fast but it is a fact that it has been involved in 2 over the bars crashes in the short amount of time it has been raced on the World Cup. Psychology and preparation are the most important factor in racing results not suspension design.
One thing that's different than 2012 is the bigger 27" wheels. This actually causes an exaggeration of the negative effects of having extreme front and rear suspension axle path imbalance like the new Demo does unless you make the frame longer in proportion to the wheels.
Protour, you brought up the sag issue, where once it sits in its travel it has essentially no rearward movement. Do you think thats why him and Brosnan are on that new, more "progressive" linkage? To keep them higher in their travel?
Speculation is for Football. I like to keep some level of dignity
As per the filename, 2012 Session's rear axle path. Flame away!
2012 Trek Session axle path:
dl.dropboxusercontent.com/u/2426014/Session2012.png
2015 Specialized Demo axle path:
2015 Specialized Demo axle path:dl.dropboxusercontent.com/u/2426014/2015.PNG
If you look at the numbers the new Demo has almost twice as much inward movement as the Session. This isn't football, but anybody want to speculate on what positive performance benefits one might get from an extreme inward axle path that rapidly changes your wheelbase and destabilizes the bike as the suspension is compressing and rebounding? Please entertain me with your ideas, Lmfao.
It turns out that the wheelbase on the 2015 Demo can be easily switched to that of a dirt jump bike:
m.vitalmtb.com/photos/features/G-Out-Project-Fort-William-BDS-2015,8934/G-Out-Fort-William-Specialized-S-Works-Demo-8,91870/sspomer,2
A - if you are not riding at those speeds, if you do not put bike into paces that make it hit obstacles giving forces those shim stacks are designed t cope with, it WILL play at your disadvantage, as everything is set fkng hard and you will end up with less grip and less forgiving suspension.
B, those guys get all those toys set up on testing sessions unavailable for average joe. If you are Athertons, you go for a week or more to Malaga or San Remo, with Fox truck full of dampers and shims, that two or three actual engineers swap for you on the fly with different presets. Those people know everything about shock setup, translate potentially vague input from Gee or Rachel and turn it into certain solutions. As to Average Joe, I am sure that most of stock suspension could be adjusted to input he gives. A fox engineer could probably set up stock 40 for average Joe by just turning knobs and make him faster than what he thinks is a good setup for him.
NO FKNG Pinkbike engineer, has such capacity in his own private testing, he may read whatever he wants, how much he wants - he will not do in two years what those guys do in a week with all the equipment available to them. So... as brutal as it seems "just shut up and ride" is a very sensible thing to do. So such link makes top riders faster, but we are not top riders...
Here, however, there are plenty of things I can point out in the comments... which probably means that I should have explained things better in the article. Anyways, there will always be those who don't believe, which is fine. I just wish I stopped replying to these type of comments as it never goes anywhere because there's often no reasoning with the commenter: give an honest, thorough review of a bike that broke and you point out how I'm not defending it in the comments. Hello, it's not my job to defend the bike, only to tell you how it rode, how it broke, and what I think. Write a nerdy little piece about a near one-off prototype rocker link on a World Cup racer's downhill bike and be active in the comments to clarify things, and you assume the worst.
You can now put your tinfoil hat back on if you like, and keep an eye on those chemtrails for me, please.
*cough* Giant *cough*
we are glad you bought a new bike now add the ride like the pros link thingy for just a couple thousand more.
:pinkies up:
Ask Anno Caro, Lopes, Cedric Gracia and Missy Giove how it felt to be a pro for Cannondale!!!
fcdn.mtbr.com/attachments/cannondale/521854d1266586036-vintage-lover-let-me-see-your-stuff-brian-lopes.jpg
Gwin smashed the tricky section of the course, he flatted near the top and still came down with rediculous speed. I think race result are 80% rider, 10% bike, 10% luck.
If gwin needs to change anything, he needs to find a tire sponsor that can keep a tire inflated on the guys bike
so they have moved from 'De Carbon' style shock to 'Twin tube' shock then? Although, as you say, not naming, as such....
Yeah Gwin had an adjustment period when switching to the big S, so what? Adjustment to a new bike and team? Sure. The beginning of the Apocalypse? No. Specialized the corporate incarnation of Lucifer? No. The baddest ass group of elite level racers ever? Yes.
I don't expect to see, and don't want to see any one dominating year over year. However, I can't believe how relaxed the Rat looks when breaking mach chicken speeds on his way to WC wins. I'm guessing he's top 3 overall for the next 5 years. Stoked to see Stevie lay it down this year and see how the dust settles between him, Brosnan and Sir Bryceland. Can't wait!!!!!!
The top 5 overall I'd like to see this season -> Brosnan, Rat, Chainsaw, Gwin, Gee-man.
btw.: i understood the reason for the last article about the demo with the longer chainstays. after all, there was a whole controversy about it..
i totally understand why you showed it, i want to see such content. but what about for exaple "spyshots" of the brand new commencal supreme v4? the completely reworked the suspension.
also hinting at "sponsorship" of articles definitely does suggest criticism, as if you are suggesting the media is simply throwing down whatever brands will pay them to say about their products. The only sponsored news on PB is when brands want word to get out regarding new products, and PB puts up posts written by companies revealing new stuff.
you totally missed the point of the article