Thread: DIY fixing damaged carbon seat stay
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Old 11-22-22 | 04:24 PM
  #15  
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maddog34
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Bikes: 1982 Trek 930R Custom, '91 Diamondback Ascent w/ XT, XTR updates, Fuji Team Pro CF road flyer, Specialized Sirrus Gravel Convert, '09 Comencal Meta 5.5 XC, '02 Marin MBX500, '84 Gitane Criterium bike

Originally Posted by vespasianus
If you don't care how it looks, but just want it fixed, you can try this:

https://www.amazon.com/Carbon-Repair.../dp/B00UMATXWY

Seat stays are not really load bearing and there are plenty of people who fixed their MTB seat stays and huck the crap out of them.
Seat stays are under a high COMPRESSION LOAD when the bike is being ridden.

Other loading that occurs in a bike frame, when ridden, are Tension, Shear, Torsional, and Cantilever loading.

update: A squealing Brake can cause Extreme VIBRATIONAL loading of the seat stays... :-D ,,, might just Shake that Epoxy into Dust.

the compression loading of the seat stays reduces the cantilever loading of the bottom bracket/chain stay interface. the comp.load changes every time you pedal.... Load Cycling Fatigue (Loosening of the Epoxy's bond to the fibers) set in and the seat stay failed by turning itself into useless fluff and chips.I've seen one frame like you describe... it went into a dumpster after a close exam and being cut to prevent reuse... that obvious failed seat stay was only the outwardly visible failure... the head tube was trying to fail also. A broken seat stay will ruin your ride.. A broken head tube joint may end your life.

in the OP's case, I'd be looking for additional cracking at the BB/Chain stays junction...

my advice to him/her? BUY A NEW FRAME.
Last edited by maddog34; 11-22-22 at 04:49 PM.
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