I have a carbon trek Emonda bicycle. Today, my rear derailleur got caught in my wheel. As a result, the rear derailleur is bent, the rear derailleur hanger snapped off, the chain got twisted and the right seat stay got scratched.

Is the scratch on my right seat stay too dangerous to ride again? It goes about 1-2 mm at the deepest part of the scratch.

enter image description here enter image description here

  • 7
  • 1
    My uneducated opinion is that it looks okay. There appears to be a metric f*ck ton of paint and primer on that frame. I’d carefully chip off all the paint in that area to assess purely the carbon damage.
    – MaplePanda
    Apr 15, 2021 at 3:37
  • 3
    @MaplePanda: In the second photo it does look quite deep and looks like it could have actually cut some carbon fibers or glass fiber.
    – Michael
    Apr 15, 2021 at 5:24
  • 1
    It looks to me like delamination has occurred. I wouldn't ride it.
    – Andrew
    Apr 15, 2021 at 18:07

2 Answers 2


I would not ride that frame as-is.

Whether it is repairable or not needs a hands-on inspection by a competent carbon fibre frame repairer in person. So you need to strip everything else off the bike and send/take the bare frame to someone who can advise professionally.

  • Thanks, I will repair it just in case Apr 15, 2021 at 15:09
  • 1
    @Bubblesphere be prepared for the fact that repair may not be (economically) feasible, then be happy if it turns out to be so!
    – FreeMan
    Apr 15, 2021 at 16:12

The seat stays are always in compression, take very little load and have no side loading. If you ride the bike on smooth roads you might not experience any further failure, but this is not ''sensible.''

The damage is absolutely repairable and may actually not cost very much. Certainly worth doing.

However, your lifetime warranty is no longer valid.

  • 2
    Thanks, I got a quote of 350$ for the repairs Apr 15, 2021 at 15:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.