im wanting to try my first tri this spring, I don’t have a road bike so im needing to get one and im cheap and don’t want to spend a bunch of money in case things don’t work out. anyway, my dad has a road bike with a carbon frame that broke this summer, it has a complete but pretty clean break across the small bar that runs between the back tire and the crank, a few inches from the back tire hub that he would probably give to me cheap or for free since he just went out and bought a completely new one. Ive heard its possible to repair carbon frames, though there isn’t a ton of info out there so im wondering if it doesn’t work out often. also most of the videos ive found on you tube aren’t complete breaks.
anyway, I was thinking about trying something like this; was wondering if anyone else has tried it personally, and how well it has held up/any specific recommendations for epoxys or carbon cloth etc.:
basic procedure- remove paint around the break, I was going to buy some 4inch carbon fiber cloth for the wrap, drench it in epoxy, wrap it several layers thick then sand it smooth and repaint. I also thought about reinforcing it from the inside which isn’t pictured in this video by possibly filling the tube with some epoxy putty or getting a wooden dowel or small piece of pvc or metal pipe or something of that nature coated with epoxy putty and sticking it into the tube to reinforce from the inside.
think this would work for at least a year or so to get me started? or would I be better off being less cheap skate and just picking up a frame for a few hundred bucks or buying something used on craigslist?
Considering that has the potential to go really wrong in a hurry, that isn’t something you should do on your own without a good deal of experience working with carbon. (although you probably could do it and use the bike as STRICTLY a trainer bike).
for safety’s sake, better off picking up a cheap road bike from the classifieds or craigslist / ebay…
That bar is called a chain-stay. A friend of mine broke one on an aluminum bike while riding and it was not catastrophic. He thought it was a wheel issue until he stopped and looked. Maybe your Dad’s experience was similar.
That’s not to say it couldn’t go really bad. It looks like a pretty high stress area, I wouldn’t risk it. If you aren’t sure whether you want to stick with triathlon, get a road bike with some decent tire clearance. You can do lots of non-triathlon things with it like commuting.
I’ve repaired carbon rims that have cracked at the nipple and they seem to last.
A complete break like you have will require a very good patching job. Never tried it myself. But if the frame is free you could give it a shot and see how the final result looks. Most likely if put several layers there and taper it, it will be stronger in that spot than elsewhere.
Haven’t bought cloth and epoxy in a long time, but I think I got it from TAP Plastics. Make sure the cloth is woven and flexible (small fibers).
Though I’ve never done it, if I had a cracked CF bike in my basement I wouldn’t hesitate to give a repair a try; that sounds like a great project. But only if it’s something that interests you. I wouldn’t do it just to save money, as I think it the options are : 1) spend $100 on materials for the repair, spend a bunch of time doing the repair, and wind up with a frame with $0 resale value. or 2) buy a 2006 Specialized Allez frame (or any other equally unremarkable, but completely adequate frame) for $125 from craigslist, ride the heck out of it, then sell it for $100 a year or two from now. Good luck!
Do it. Carbon repair is not exactly rocket science. It is a low tech solution that amounts to splinting the broken tube. Overbuild the area with a lot of wraps and it will likely be stronger than the original chainstay.
Back in 2000 I had bought a used Vittus Carbone 9. I road that bike in my first three Ironmans. After the last one I noticed that I would drop my chain every time I stood up on the pedals. Took me a while to figure out that the seat tube had become detached from the bottom bracket. Every time I would put pressure on the crank the top tube would unseat about a 1/2 inch. Luckly the tube went into a lug, I tried a DIY repair. Cleaned the lug and inside of the tube as best as I could and applied a generous amount of epoxy. It held, for about a day. I always believed that it would have been a permanent fix if I could ever have cleaned the inside of that seat tube completely; too much grease and it was just too hard to get a rag in there. I was sorry to see that bike bite the dust as it had a very smooth ride (and it was my first decent bike I owned).