Bicycle Mechanics - minor incident with Trek 2100 carbon stay - is this frame trash?

I hit a pothole on a bridge today which caused my stay-mounted blinky light to drop down and rotate inwards, where it was caught between the left seat stay and spokes and spun forwards. This is my recreation based on the damage - at the time I thought it was just a broken spoke from the sproingy sound. I have trued the wheel but I found some damage on the inside of the stay.

I attached a few photos of the inside of the stay where the damage occurred. The vertical marks seem to just be surface scratches - the horizontal mark is actually where the surface material is separated. It is less than 180 degrees around the stay - there are no marks on the outside. Not understanding a lot about how CF materials are built, I'm not sure if this is merely cosmetic, or structural. I'm taking it to the Trek dealer tomorrow but I'd like some unbiased opinions of how serious or minor this might be. I have a charity ride this weekend that I hope I can ride in with this bike.

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Seatstays are the most forgiving of all the frame tubes. The failure of one rarely leads to a crash. I'd clean it up, cover it with a foul piece of trim to seal it and continue riding the bike. I'd also inspect it from time to time for any sign of spreading damage.

If you're concerned, you can also splint it a number of ways which will keep it together.

It appears to me to be cosmetic damage but let the Trek dealer decide. Clear fingernail polish if applied carefully in thin layers will do a pretty good job of covering the scratches.

In picture #2 u can see a tiny crack, the good news is that u could fix it yourself using duct tape! :D

Now seriously, some companies sell kits to fix stuff like that. Doesn't look that is that hard either.

Second option is to use the thing used to glue carbon frames and cover the tiny crack, then sand and reclear because doesnt look like that bad. At least is fixable. I would use a CF patch to play safe tho.

Good luck and put the light somewhere else now :)

Trek 2100 is 3 main tubes carbon with aluminum stays both chain stays and seat stays.

Trek 2100 is 3 main tubes carbon with aluminum stays both chain stays and seat stays.

This is true, only the 3 main tubes are carbon fiber. The stays, head tube, and lugs are aluminum.

This is true, only the 3 main tubes are carbon fiber. The stays, head tube, and lugs are aluminum.
Not necessarily. My 2007 Trek 2100zr has an aluminum mainframe and chainstays, with oclv carbon seatstays.

Trek 2100 is 3 main tubes carbon with aluminum stays both chain stays and seat stays.

Don't know what model year yours is, but the 2005 also had OCLV CF stays with a Alu frame http://www.trekbikes.com/us/en/bikes/2005/archive/2100

It's carbon and there is a good chance of failure, I wouldn't risk it, repairable yes, but would have to weight up the cost of a professional repair vs a new frame. Have a look at Busted Carbon for stay failure.

Wouldn't hold much hope for the ride at the weekend as it is, would expect it to fail when you are furthest from any kind of support.

If you are the orginal owner, would be worth looking at the Trek crash replacement policy.

Given there is a giant "OCLV Carbon" decal on the seat stay, and it fractured unlike metal, I think I'm safe in assuming it's carbon. I was thinking it was a 2006 model (see my sig) but those say TCT carbon so this is probably 2004 or 2005.

Missed that bit in you sig; so would say OCLV stays, would get it checked out by you local dealer.

Sorry missed that so Calfee Design in California could repair the stay and they have a price list online.

Seatstays are the most forgiving of all the frame tubes. The failure of one rarely leads to a crash.

Yea, if it was any other tube, I'd be leery of riding it, but a couple of turns of duct tape or something will see you right IMO.

Cause it's in compression, it should be fine... just keep an ear out for further damage when you sprint on it.

Personally, I wouldn't trust the integrity. I'm 99% sure if you take it to a Trek dealer, they'll say it's toast. They'll either offer to send it to Trek for repair (check your warranty) or recommend a carbon fiber repair shop. You may not have one locally though.

What do you have to lose to have some look at it?

What do you have to lose to have some look at it?

Time.

Most shops won't want to risk tarnishing their reputation by saying a questionable gouge is safe to ride. The safest thing they would say is: I wouldn't ride that....here's a brand new bike that looks like it would fit you.

Maybe if the OP knows of an experienced mechanic personally who can give a honest opinion or better yet a custom carbon fiber bike builder...good luck.

I've repaired much worse damage to a Trek carbon seat stay using a kit I got from Carbonology (http://www.carbonology.com/kit-no-2-the-tube-repair-kit-size-b-p-240.html). I rode the bike for 5,000+ km after that with no issues.

The safest thing they would say is: I wouldn't ride that....here's a brand new bike that looks like it would fit you.


Give that man a cigar! I did take it to a Trek dealer as promised, and the mechanic's final statement was "I wouldn't ride that." However, he said the Trek warranty might give me some (not much) money towards a new bike/frame even though I'm not the original owner, he also gave me the name of a local shop that builds and repairs CF, and he recommended the repair route as the most economical.

For a bike that only cost me $600 nearly new (maybe 10 miles on it) on ebay, I'm not sure that it's worth what's probably $200 minimum to repair.

Honestly all I wanted was a judgement of whether the damage was cosmetic or not; I fully expected to be told not to ride it if the damage was not obviously cosmetic, as the shop simply has no other choice in today's lawsuit-happy environment.

Thinking about this a little more, it almost seems that with the fragility of CF, it only makes sense to buy a frame with any CF components only from a dealer, fully expecting that there will be a failure during the "lifetime warranty". Even if I can get the same thing for half price on ebay, if it fails once, I'm already at about the same price.

Oh, and I did a 4-mile test ride on Friday, then the 44-mile charity ride on Saturday, with no ill effects. There are no changes in the dimensions of the crack. I'm looking at repairing and/or replacing the frame anyway, but it doesn't seem like I need to rush. If I had been on the ball I could ride one of my old bikes, but they are both in the midst of very slow complete rebuilds.


I've repaired much worse damage to a Trek carbon seat stay using a kit I got from Carbonology (http://www.carbonology.com/kit-no-2-the-tube-repair-kit-size-b-p-240.html). I rode the bike for 5,000+ km after that with no issues.
Thanks very much for that link and your experience! I am very much a DIY type and it definitely looks doable.

Give that man a cigar! I did take it to a Trek dealer as promised, and the mechanic's final statement was "I wouldn't ride that."

Any bike dealer will give you the same line regardless of brand or any specificity related to each individual accidents. There's no easy way to test the frame for soundness, economically. No one will ever say that your frame is ride with anything that even looks like it could be a crack.

Any bike dealer will give you the same line regardless of brand or any specificity related to each individual accidents. There's no easy way to test the frame for soundness, economically. No one will ever say that your frame is ride with anything that even looks like it could be a crack.

Right, that's why I said "I fully expected to be told not to ride it if the damage was not obviously cosmetic, as the shop simply has no other choice in today's lawsuit-happy environment.". However, 531phile deserves a cigar for predicting the EXACT words that the mechanic said.

Now, what do folks think about my question whether frames that include CF should only be bought from an authorized dealer, since they seem highly susceptible to fail and need warranty replacement?

Now, what do folks think about my question whether frames that include CF should only be bought from an authorized dealer, since they seem highly susceptible to fail and need warranty replacement?

Any material can fail, not just CF, most of the time, if the CF would fail, then so would any other material, If your seat stay hadn't failed, then the force would have been taken by the wheel, and you would probably have lost several more spokes & been thrown off.

Authorised dealer normally = bike shop, whcih is where most CF bikes will be bought from in the first place.