First spotted at Crankworx Whistler last year in prototype form, today Specialized unveiled the covers on an all-new 2015 S-Works Demo Carbon. Aaron Gwin and Troy Brosnan will race the bike this weekend at the Mont Sainte Anne World Cup, and it will be available to the public in January 2015.

Prototype sightings have filled the forums in recent weeks, but Specialized insisted we keep things quiet until August when the bike is officially launched at Crankworx. Consider this a nice little sneak peek with full details to follow soon.

2015 S-Works Demo Carbon Highlights

Several details can be inferred about the new design watching the intro video and looking at the photos:

  • 650b wheels
  • 200mm travel
  • Full carbon frame
  • Custom tuned Öhlins TTX22M rear shock
  • Asymmetric design
  • Internal cable and brake routing
  • Press-fit bottom bracket
  • Molded chainstay, seat stay, and downtube guards
  • 12x135mm rear axle

“The goal when we started was just to make the fastest downhill bike that we’ve ever come up with. We wanted to lower the center of gravity, increase its capability in terms of handling, make it lighter, pedal better… everything we could think of we threw at this new bike. It’s got a whole new look and feel to it.” - Sam Benedict, Specialized Bicycles

The new asymmetrical seat tube is a weight savings measure meant to help keep the center of gravity low. Apparently it’s every bit as stiff the previous design. The design also allows for easy access to the Öhlins TTX22M rear shock.


[Updated] The bike's geometry is not yet confirmed, but various sources have leaked geometry for an updated 2015 aluminum version of the current 2014 design which will also continue into next year. Three sizes designated Medium, Long, and X-Long will be offered with similar seat tube heights. Here are the reported numbers:

  • 63.5 or 64.3-degree headtube angle
  • 76 or 76.8-degree seat tube angle (effective)
  • 393, 417, 417mm seat tube length (M, L, XL)
  • 430mm chainstay length
  • 347 or 357mm bottom bracket height
  • 1207, 1228, 1235mm wheelbase (M, L, XL)
  • 573, 594, 612mm top tube (horizontal - M, L, XL)
  • 419, 439, 456mm reach (M, L, XL)

If these figures are accurate and comparable, geometry will be on par with the 2014 Demo in many ways but feature slightly longer chainstays, a longer wheelbase, and longer reach.

“Handling wise there are a couple of things a little bit different about this one. The rear ends a lot lighter. It pumps in and out of the holes smoother. This bike definitely has potential to go faster than the other one.” - Troy Brosnan

The FSR suspension design utilizes a concentric main pivot at the bottom bracket - something not often seen anymore in the downhill world. Also interesting is the use of a 12x135mm rear axle with square shaped design for added stiffness. The move back to a 135mm rear end is likely the result of wanting less weight and more clearance in tight situations.

“It’s pretty crazy how good it handles. That’s probably the thing I noticed the most as soon as I jumped on it was how quick you change directions and how hard you can slam it into turns. It’s just a really lively bike but when you get it into bumps it eats them up really well. It’s kind of the best of both worlds. That’s kind of what we were really working towards. To get a fast bike but one that really takes the big hits. I think we nailed it.” - Aaron Gwin

Keep an eye on for more details. Is it truly the fastest downhill bike Specialized has made to date? We’ll have to see how things shake down in Mont Sainte Anne. Also stay tuned for our ride impressions right here on Vital MTB.

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  • ChrisG

    8/29/2014 2:25 PM

    A good analysis by Antonio Osuna of the 2015 Demo kinematics has been published at

  • esstinkay

    8/19/2014 3:04 PM

    interesting 2015 demo simulation:

  • ChrisG

    8/14/2014 8:32 AM

    Two articles, one on this site (,276) and one elsewhere ( confirm the substance of my earlier comments - things I supposedly couldn't know according to some. (note: I am not saying these writers share my opinions about the new Demo, they don't, only that they give the same account of the facts about the kinematics and structural features of the bike.)

    This siite - - helps give genuine information about how the linkages of real bikes work. You can know plenty about how a bike rides without riding it. The alternative is to believe the fields of design and engineering are a waste of time.

  • groghunter

    8/14/2014 10:23 AM

    Hah, being right on the internet seems to be pretty important to you.

    I'll take the bait: you were certain it would be prone to flex. you simulated the linkage in software. Did any of that account for a square axle that is supposed to take the place of the cross bracing? less movement at connection points can make fasteners an effective cross brace, & Specialized obviously accounted for the reduced stiffness & compensated for it, otherwise, in testing, somebody like Gwin who runs his bike's suspension super stiff would have complained that it was flexy, & they would have gone back to the cross bracing.

  • erwinmruiz

    8/1/2014 11:54 AM

    Great looking bike, the industrial designers sure did a nice job

  • Scrumpnation

    7/30/2014 9:53 PM

    Anyone know what the second song is? need it for my next 20 minute pov edit.

  • munichrider

    7/30/2014 4:09 AM

    Is it only me who is meminded of the well aged Rotec RL9 with Lawill suspension?

  • Oz_Taylor

    7/30/2014 5:33 AM

    Yeah I thought that with the big swingarm and concentric pivot, but this isn't a full floater, and the brake isn't floating either. I used to ride a Yeti DH9, nothing brakes like that that thing, you could literally back it in over braking bumps without the back end skipping around. Loved the Lawwill stuff!

    Edit - just realised you are referring to the latest Rotec with the single swingarm. Yeah it definitely has a look of it, especially with the upper swingarm blacked out like that.

  • ChrisG

    7/30/2014 11:51 AM

    Yes, the suspension linkage on this bike has more in common with the Lawwill link than it does with Specialized's own expired Horst-link patent. "FSR" is by now little more than a marketing term.

  • Oz_Taylor

    7/30/2014 12:03 PM

    I agree I guess it is a 4 bar linkage at the end of the day. I think the thing that set the early Lawwill bikes apart was having the rear caliper mounted on a floating carrier that pivoted around the rear axle, rather than having it mounted to the same link. I don't know facts and figures but in my experience, trailing the back brake and drifting that DH9 into bumpy turns made it awesome fun to ride! Things have moved on so far since then, and those early Lawwill designs were complex and heavy. This demo is such an elegant solution. In fact it reminds me of a Ducati 996, especially in red with the Ohlins shock. Maybe in 20 years these will become art for rich guys to hang on their walls :-)

  • ChrisG

    7/30/2014 12:11 PM

    Sorry, my post was a bit of a moving target - ill considered expression, my bad. You were posting as I was editing. I was very interested to read your post though.

  • ChrisG

    7/30/2014 12:37 PM

    The Yeti DH9 has been thoroughly analysed by Antonio Osuna (see who notes the big difference that the little floating carrier makes. You are completely right about the carrier being crucial to the good braking performance of the Yeti and other similar bikes.

  • glucia805

    7/30/2014 10:32 PM

    The lawwill type designs were evil without a floating brake. They truly brake jacked. Same goes with the old Storm Cycles system.

    All the dh bikes back then where heavy and pedaled like crap

  • Oz_Taylor

    7/30/2014 1:21 PM

    Interesting stuff, thanks for the link! Seems the brake carrier was there out of necessity to make the system function. One thing the graphs do confirm is that it pedalled like s**t., especially weighing in at around 45lbs :-)

  • Tifereth4

    7/29/2014 10:34 PM

    Pressfit bb on a dh bike...a specialized one at that. Lolol

  • ChrisG

    7/29/2014 7:43 PM

    Besides the carbon artistry what is new is the linkage. With any linkage what you are concerned with are its structural and functional - wheel path and kinematics primarily - characteristics. So how does this new bike rate on that scorecard.

    Wheel path and pedal feedback - not too dissimilar to the old bike (probably)
    Anti-squat - the new bike is greatly improved (i.e. more pedaling neutral)
    Anti-rise - braking will be different on the new bike but AR will continue to be low which is generally considered to be good for traction when braking
    Leverage rate - that was alright on the old bike, the new one won't radically deviate

    There is nothing wrong with or especially notable about these functional changes. The same result was readily achievable with relatively small changes to linkage pivot positions on the existing bike. Where the new bike is let down is in the structural characteristics of the rear end. The rear axle is mounted on two separate linkage pieces on each side of the wheel - the single rear end seatstay component that the wheel mounts to, common to all Horst-link bikes, is gone. These separate pieces on either side of the wheel join to the other linkage bars via a couple of pivots within the circumference of the wheel (looked at in side view). In general full width pivot axles are better than aligned pivots on either side of the wheel and if aligned pivots are used it is important that they are near a structural member bracing drive and non-drive sides together.

    I am not impressed by the new design - it appears to be prone to flex. To what extent that concern will manifest itself, is hard to say. Just how noticeable flex becomes will depend on the quality of the pivots, bearings and carbon structures used.

  • Nicholast

    7/29/2014 8:03 PM

    You could have saved a couple key strokes and just said "looks flexy."

  • sspomer

    7/29/2014 8:14 PM

    Lol nicholast wins.

  • ChrisG

    7/29/2014 11:42 PM

    Had I done that then someone could respond "doesn't look flexy to me". I prefer to make people who disagree with me work much harder than that.

  • Oz_Taylor

    7/30/2014 12:42 AM

    Have you seen wheel path diagrams? Have you ridden the bike or spoken to somebody who has first hand experience of the pedaling/braking characteristics? Do you have any facts and figures for the stiffness of the frame? If the answers are no, then your entire comment is pure speculation.

    Whilst we are speculating, I'll do a little bit of counter speculation for arguments sake :-) Looking at the thickness of the chainstay and the size of the main bearing, I don't think stiffness is going to be an issue. It also looks plenty wide where the upper link attaches to the main frame, so this should help lateral stiffness. In my opinion a bike can be too stiff - engineered flex can be a good thing. In any case, I'm sure Specialized have done their homework and I'm looking forward to having a ride on one.

  • ChrisG

    7/30/2014 12:54 AM

    I emulated the new linkage using a modified version of the publicly available Status linkage geometry in the library of bikes that comes with the Linkage program. That is not an exact method but the speculation in my comments is well informed speculation.

  • esstinkay

    7/30/2014 10:32 AM

    To dismissively say you're not impressed with the new design is just arrogant.

    Some thoughts about your assertion of flexy based on my *assumptions*:
    - quote "lighter while maintaining the stiffness" would suggest that rigidity was a priority in the design. I know first hand that previous year models are not flexy
    - the upper linkage (attached to shock) appears pretty beefy
    - the lower concentric pivot is about the size of my wrist
    - the lower stays are one single piece

    here's a good angle:

    How you've determined the other characteristics from watching a video is a head scratcher though.

  • ChrisG

    7/30/2014 10:08 PM

    By the way, I didn't determine anything from watching the video. I used the geometric method of calculating anti-squat and anti-rise from the perfectly good photograph on this page. I had already looked at the dynamics of this sort of linkage from an emulation I tinkered with in the Linkage program quite some time ago. As it happens there is now a carefully developed emulation of the new Demo by Kryatof Jetmar that sits permanently in the public domain library of Linkage and it confirms the points I made about the new linkage function, although while the new bike is more pedaling neutral the improvement is modest rather than great. With the new details that are available our understanding of how the suspension functions will get more accurate but the general picture is already clear.

  • ChrisG

    7/30/2014 2:37 PM

    There is nothing arrogant in my comments. It has all been common design practice up until now. Look closely at the image you have made reference to. Imagine pulling the axle out and moving your arm forward in the open space between the two sides of the (multi-part) swingarm. You arm will go past two sets of pivots without cross bracing between the drive and non-drive sides before being obstructed by any sort of structure that joins the two sides of the swingarm. There would be very few bikes like that out there. That is because t is not a good idea to have too many pivots in the suspension linkage without proper cross bracing to create a stiff or flex free structure. Dual short link bikes commonly use full width pivot axles and Horst-links have always had a single piece seatstay that braces the seatstay/rocker pivot very effectively. Without much flex elsewhere and with the rear wheel axle also binding things together the unbraced chainstay pivot of the horst-link has worked well, without much flex, in practice. That you can move your arm around freely in this big void between the two sides of the swingarm of the new bike without finding any cross bracing near either of the mentioned pivots means that Specialized has thrown out the rulebook that everybody previously used. The point I have made is old school. From my standpoint (and I would say the standpoint of prevailing engineering practice) Specialized is violating a basic rule. No doubt, they would say, carbon changes everything.

  • boomslang

    8/16/2014 8:41 PM

    @ChrisG Great effort in applying sound engineering judgement. Your approach is good though your conclusion leaves out a number of factors. We have discovered that the new rear triangle is actually STIFFER than the old bike, through both controlled lab testing and field testing. This was achieved by oversize tubes, specific carbon layup, the addition of 2 bearings, upsizing of 6 bearings, wider bearing stance at the pivots and the rear square axle. All at reduced weight.

  • ChrisG

    8/29/2014 2:51 PM

    @boomslang I am very interested in what you have said. You seem to have an intimate knowledge of the new Demo. Are you connected with the Demo design group or are you researching this in some other capacity?

  • boomslang

    8/29/2014 9:17 PM

    ChrisG - I am the lead engineer, Jason Chamberlain from Specialized.

  • ChrisG

    8/30/2014 9:51 AM

    @boomslang Well, thank you for your informative comment. I'm sure that there is a lot there of general relevance for DH bike frame design and construction. You wouldn't be too shocked to learn that there are those of us who continue to consider the older frame design to be the better one overall. So, I welcome the news - widely reported and I hope reliable - that a 27.5in version of that bike will continue to be available in aluminium.

  • scarface

    7/30/2014 2:59 PM

    Y'all lost me at "so I haven't actually ridden this bike yet..."

  • esstinkay

    8/21/2015 8:43 AM

    a year later and the bike is actually performing quite well

  • groghunter

    8/21/2015 9:22 AM

    Only without a chain :D

  • bjenson

    7/29/2014 6:02 PM

    lol at the "zoom" noises added during gwin's riding section around 2:07. zoom zoom!

  • Mr. P

    7/29/2014 5:35 PM

    That mono seat stay is pretty cool, but the really interesting bit is what Specialized is doing with that Horst Link. Concentric BB main pivot, dropped chain stay pivots and short seat stay pivots... kinky! I'd like to hear the thinking on that.


  • bturman

    7/29/2014 5:44 PM

    Count on hearing more in a few weeks.

  • Mr. P

    7/29/2014 5:32 PM

    I miss the aesthetics of 26" wheeled bikes crazy slack head angles...

  • monstertiki

    7/29/2014 4:17 PM

    New bike looks rad! But this new bike better not hurt my fantasy dh team. I have both gwin and brosnan on my roster...

  • MoneysWorthLife

    7/29/2014 1:29 PM

    It still has a derailleur!

  • F1234K

    7/29/2014 1:43 PM


  • Bigburd

    7/29/2014 1:57 PM

    Did you watch that video about the SRAM pit truck and how many mechs they went thru at Leogang and Ft bill ? it's clear there is shit load of money to be made from people replacing the archaic rock testing device..

  • iceman2058

    7/29/2014 12:27 PM


  • OCsponger587

    7/29/2014 12:17 PM

    the seat tube height stays low through all sizes. i wonder if troy will ride the long or xl on fast tracks? troy has done good on the current bike this year. i bet he doesnt want to switch yet. i wouldnt

  • onenerdykid*

    7/29/2014 12:27 PM

    this bike wasn't designed in the last month or something- it's been in the works for at least 12 months (as the spy photos prove). I'm sure the aluminum 650b he has been using was designed as closely to this as possible.

  • OCsponger587

    7/29/2014 12:40 PM

    the suspension layout is totally different. there ride may feel the same but knowing the bikes are different could be a total mind f*er for a top pro who has won on one bike and now has to change in the middle of the season. just sayin

  • onenerdykid*

    7/29/2014 1:28 PM

    true, but he's shown this year that he can bounce between different bikes at different races and still keep it totally together, rather successfully. He's said he has put time in on the new bike and I bet he looks forward to being on it.

  • Bigburd

    7/29/2014 1:59 PM

    Troy has more talent than should be allowed for one person , you could put him on a v-10 or a kona operator and he would slay like normal.

  • Nicholast

    7/29/2014 12:10 PM

    I had a current generation Demo and swapping shocks and springs or removing a shock for service was a tedious and slow chore. They really took that feedback to heart on the new design, didn't they. Not sure I love the looks of that feature, but from a functional standpoint, that should make shock tuning a whole lot more welcoming.

  • savdog

    7/29/2014 12:21 PM

    undoing 2 bolts & pulling the shock out of the frame is tedious & slow ??

  • Nicholast

    7/29/2014 1:07 PM

    I thought so. Wiggling a Vivid Air in and out was chore; it certainly wasn't quick and simple.

  • groghunter

    7/29/2014 1:40 PM

    Until recently, I had an '05 demo, which was far harder. as in, remove the whole top linkage, which uses loose washers that you have to try to keep together with the bearing while putting the middle of pivot back between them. had to resort to "gluing" them in with grease, & still trying about 20 times before I got it.

    edit: I also forgot that it didn't use a standard DU bushing at the rear shock eyelet: instead, two conical shaped washers with the same retention problem, plus because they're conical, they would move so far off the bolt axis that you couldn't get the bolt through, or wiggle them into place. page 15:

  • ryan_daugherty

    7/29/2014 12:10 PM

    The 12X135 axle is a new/old ploy for a new/old standard to force all of us to up/downgrade our current bikes and then be dicks to the sucker 12X150 hold outs. #12X150ISDEAD #GETWITHTHETIMES

    Next we'll see them go back to 26" wheels to save weight.

  • Cougar797

    7/29/2014 12:20 PM

    Well in all fariness to them, the demo has always come in or had a 135mm option. 2011 was the first year they had a 150mm rear end but even then the sworks and high end models came with 135mm. Frame only and the "lower pricepoint" builds were the only ones sold in 150mm.

  • groghunter

    7/29/2014 1:41 PM

    Specifically because the racers wanted it, too, there's lots of quotes where they praise the skinnier rear end.

  • esstinkay

    7/29/2014 3:01 PM - hm sure enough, 135mm rear axle on the demo 8 II and the sworks models.

  • onenerdykid*

    7/29/2014 12:04 PM

    Thanks for providing more details on the specs and features than other websites! I heart Vital.

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