Today a N.O.S. 2016 Stumpjumper FSR carbon frame set arrived, and I'm not impressed with some aspects of the way the carbon fiber front triangle appears. My CF experience is limited having only owned road forks with CF blades. Otherwise, perusing the offerings at a bike shop and a test ride or three and lots of reading about it generally covers my experience.

I am a believer in CF technology and feel it's proven itself as a worthy structural material. However, I certainly do not like the way it looks, especially as it is rendered on this bike frame. The following photos describe best what I mean, and while I have a multitude of questions, most are probably wanting subjective answers (fine by me, not this forum). Does the frame look "right" to you considering your experiences? I'm concerned about possible flaws or repaired damage. There was no indication from the seller that this was anything but a brand new frame, one of the first "6fatties" having a 148 boost rear end which is aluminum alloy (the rear triangle). More background: frame is a new, 2016 Specialized Stumpjumper FSR Carbon "6Fattie" 29/27.5+ purchased on eBay from the seller, Specialized_outlet_store that seem to be truly connected to Specialized though that isn't a certainty. The frame's serial number did register correctly on Specialized's website. The color scheme in the areas of concern is called, "gloss silver tint carbon." Also, I am taking these issues up with "them" (both the seller and the actual Specialized company) via email and will visit my LBS, a Specialized dealer, after the holiday.

The color scheme is "gloss silver tint carbon"

Pretty prominent facing aspect to be showing such rough weave

What exactly is this at the seat tube?!?

Do you feel this looks like a repair of a damaged frame? Amount of material effects weight, but why wouldn't or couldn't one put a layer of consistent weave for cosmetic purposes on the top to hide the inconsistencies of the structural direction? Who in their right mind (@ Specialized) thinks this looks ok, considering the areas of concern are key aspects that one's vision is drawn to? Finally, the seat tube area pictured: is this normal or a flaw? The surface is perfectly smooth and a tapping test doesn't reveal any changes in tone over the area. Thoughts? Opinions? Concerns?

  • 2
    Are you positive this is authentic? I'd have so many doubts.
    – Criggie
    Commented Jul 3, 2021 at 6:50
  • 3
    That's how a typical CF layup on bicycles looks like, you are worrying over nothing. I hope you did not look inside the tubes. Commented Jul 3, 2021 at 8:19
  • 4
    Have you tried registering the serial number on Specialised's website ? As the initial owner, it should be available for you. If the cloner has simply put the same serial number, or a made-up number on the frame, then it won't confirm. Do let us know what happens. Registration page is specialized.com/us/en/support/bike-registration you will need to "create an account" too.
    – Criggie
    Commented Jul 3, 2021 at 12:26
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    @Criggie Yes. I've registered both myself (already had an account but no bikes registered) and this Stumpy on Specialized's official website and it confirms the correct model, etc.
    – Jeff
    Commented Jul 3, 2021 at 16:20
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    I sense the frame is authentic but still wonder if isn't a cosmetic reject refused by a dealer or something like that. In researching the model year 2016 on the Specialized website, they did offer this model and color scheme as a frame set. This unit has no signs of having been built up previously. The "6Fattie" concept was brand new and focused on 27.5 wheels, 3 inches wide, and the whole 27.5 class of MTB was quite blunted in it's opportunity for growth by the surge in popularity of 29ers right on it's heels. Thus, I felt it reasonable that this frame was still on the market.
    – Jeff
    Commented Jul 3, 2021 at 16:58

3 Answers 3


You’d have to be the first person I’ve encountered who explicitly dislikes this “raw carbon” finish. It’s completely normal and just an artifact of the way bikes are made. That is, bike frames are laid up from small sheets of carbon; they are not woven together into a seamless contour or something. All you are seeing is the boundaries between carbon pieces.

As to why bikes aren’t wrapped in a weave finish, I would assume it’s because of market desire. People prefer seeing this raw UD finish instead of a woven one, so that’s what the manufacturers make. I personally think UD looks amazing, as I can see the figurative muscles, tendons, and sinews that make up your bike, which is just awesome. Some brands do do woven as the outer layer though, eg. Unno.

The downtubes of these Specialized bikes are post-processed internally I imagine to facilitate using the SWAT box. The inside usually isn’t that clean. Shreds of expansion bladder, epoxy drips, etc.

  • Is UD an acronym for something? Ugly Duck perhaps? Lol. Well, the trend continues as I've often questioned (mostly to myself) the reasoning behind what many others find desirable, tasteful, or fashionable. Some things are beyond me. I'm quite ok with that
    – Jeff
    Commented Jul 3, 2021 at 18:37
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    Uni Directional i.e. all fibres going in the same direction, not woven in a criss-cross pattern.
    – Michael
    Commented Jul 3, 2021 at 19:09
  • @Jeff why not paint it matt black if you don't like it. Numerous raw carbon frames have the finish you see on yours and there are many, many questions about it on bicycles stack exchange.
    – Noise
    Commented Jul 3, 2021 at 19:25
  • @JoeK ya, I noticed the red paint adequately covered the CF look I don't care for. Focus at the moment is getting over how it looks to me and deciding it's the real deal. I don't anticipate any changes to the finish until next year.
    – Jeff
    Commented Jul 3, 2021 at 20:04
  • @Jeff Yea, it’s just preference. I find the look of unidirectional really nice, as it has depth and you can see all the layers and stuff. In comparison, woven just looks like somebody slapped a bunch of cheap faux carbon vinyl wrap over the bike. I do believe woven is technically a better outer layer from an engineering perspective because it has better abrasion resistance, but market forces prevail.
    – MaplePanda
    Commented Jul 3, 2021 at 20:54

After an overnight and much of today wondering if perhaps I'd been hoodwinked on an eBay deal that seemed quite legitimate for the few weeks I pondered this specific purchase, a cool breeze of relief arrived this evening in an email from a representative of Specialized bikes. In summary, the bike is authentic and the seller is truly a branch of Specialized USA. As a couple of fine Bicycle SE netizens tried to assure me, the look of the carbon fiber is entirely normal, and I'll be damned if many folks even like it. Desire it even. I'm not one of ya, but I'll deal with it. I'm certain that as the build progresses my mind will be opened to a few more "bike-worldly" things. Even now, I'm wrapping my brain around the fact that there are no less than 4 differing thread pitches for through axles and having a wheelset with Shimano Deore hubs does not necessarily mean one should rush out and obtain a Shimano E-Thru lever axle, thinking how wise to be mindful of getting the Boost model and not the mere 142mm hub version. After all, this Stumpy is one of the first to sport the broader 148mm Boost rear end. Well, I was wrong, and the words of a former coach came to mind: "Hargis, you think you know all the answers, but you really don't even know the questions!!" True, since in the case of this--and any-- rear hub's through axle, a significant aspect of being able to work for a particular bike after the more obvious details of correct diameter and shaft length, is the length of the axle's threaded portion as well as the thread pitch. These details must match up with the requirements of the frame's thru axle area into which the axle will be threaded. Well, not only are the specs for this aspect of a bike frame curiously absent from the laundry list of lengths, widths, and geometry nuances offered readily by the manufacturers, but also there exists about 4 different "standards" being used and even these may differ between the mountain division of a brand and it's road, sister division.

I wonder, is the pain I feel behind my eyeballs that of my mind becoming more open? Or the squeeze of growing cynicism? Perhaps the answer is in the beautiful weave of raw carbon fiber : - \ Anyhoo, here's the email reply from Specialized regarding the issues I continue to process in regards to my Stumpjumper FSR Carbon frame set. This was prompt and thorough, for which I am grateful. I sent my email to them maybe as long as 2 hours after the bulk of the Stack Exchange answers and comments had been offered (and thank you all for that!):

"Hi Jeff thank you for reaching out!

The ebay page in question in fact belongs to our company, and I can see the registration of that frame attached to you. So rest assured that as far as I can see, you've purchased an actual Specialized Stumpy frame! As far as the carbon fiber is concerned that is normal. The method in which our carbon frames is made is extremely guarded and proprietary to Specialized, but I can tell you that it is normal for a black raw carbon frame. All I can tell you is that it is a result of the layup of the carbon when the frame is being constructed. I personally think it adds to the charm of our carbon frames, as no two are alike and you'll be able to easily identify your frame by the small details you've photographed. Let me know if you have other questions!

Ride On!

René | USA Rider Care Specialist | [email protected]"

  • Easy way to avoid all this confusion is to stick with '90s/'00s 26" hardtails. You even get more chainrings for your money :)
    – Armand
    Commented Jul 4, 2021 at 5:43
  • @Armand Been on nothing but those for my mountain bikes. 08 Spesh Rockhopper and an '02 Stumpjumper. Time to get with the big boys
    – Jeff
    Commented Jul 4, 2021 at 5:59

tl;dr: if that shop is an official Specialized dealer, and that frame is sold by Specialized with all the accompanying license tags and co, please send me 1000$ as soon as possible.


Zainab Shamsuna Ahmed

Finance Minister of the Federal Republic of Nigeria

ok, more seriously:

a) the store does not look at all an official store. See the use of non-capital lettering, the missing "S" from the logo of Specialized and the complete lack of impressum/disclaimer and what's not. I am not an expert in decals&co, but those can be reproduced in a very realistic way without much effort. Add a layer of whatever primer and they will look like the original ones ... for a couple of years or more (or less), according to sun/weather/sweating exposure.

b) adding a layer of carbon for cosmetic purpose is not cost-efficient: it means you have to take the frame, and put it again in the press / oven where the frame was formed. Or you must have the master of weaving employee, whom would as is unique job fix the 10-100s of frame per month with some defect: much better to invest the same money in a better tool to produce the frame, reducing these wrong frame to 1-10s. If you have then 1% of the frame coming out "wrong", then you are good to go in throwing them away. And someone will pick it up and try to sell it as legit through doubtful stores ...

c) tapping the frame sounds ok? good, then instead of surveying it with some grams of a coin, try to "tap" it with your full weight plus a backpack full of stones. Something like laying it on the ground and jumping full force on it (put adequate stress spreader/shock absorbing material on the dropouts and other sensitive parts). If it is still sound, it may be good. If you do not trust yourself doing that, well, that tells you a lot about how much confidence you can have in that frame.

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