Your carbon bike is cracked broken or you want to close holes from rivets? I show you how to laminate carbon fiber simple at home with good results. The simplest way to tell if carbon is cracked is to run a clean rag along the tubes to see if it snags on loose fibers. You can also tap on an area that's been impacted and listen to the sound — a dull 'thwack' is a bad sign, but a clean, crisp 'tick' might mean you're okay. Whatever the material, there are many things to look out for when buying a second-hand bike. However, carbon has its own peculiarities that set it apart and make it trickier to assess. My carbon fiber road bike had a pretty serious gouge in the downtube from dropping the chain. It happened years ago and I’ve ridden it probably 15,000+ miles since then without issue. I figured since my frame hadn’t broken in the intervening years, the damage wasn’t structural. It was, however, an eyesore.
- Tell If Carbon Fiber Bike Cracked Leg
- Carbon Fiber Road Bike
- Tell If Carbon Fiber Bike Cracked Skin
- Carbon Fiber Road Bike
I'm wondering how many people with carbon frames have had problems with cracks. And if so, what caused them?
I bought a Madone 4.7 WSD back in October 2010. Just over a year later, I discovered a crack in the top tube while I was cleaning the bike. I have no idea what caused it -- I've never crashed, I haven't dropped the bike or knocked it over or dropped anything on it. There has been no significant impact to the frame.
The LBS manager sent it to Trek, where they looked at it, scratched off a bit of paint at the end of the crack, and said they thought it was most likely caused by an impact (and therefore not covered by their warranty). In order to give me a definitive answer, they said they would have to cut off the top tube to look inside. After doing the math to determine the cost of buying a new frame under their replacement discount program (20% off) vs having the crack repaired, I asked the LBS manager to tell Trek to just return the bike to the shop so we could send it off to Calfee for repair.
I'm still waiting to get it back -- apparently Calfee has finished their work and it's in transit now.
I know carbon fiber can be very strong. But now I'm starting to wonder about the strength of mass-produced bike frames. Has anyone else had damage that was not caused by an obvious strong impact to the frame? Is this a fairly common problem or did I just get a lemon?
BTW the cost estimates were ~$1200 for a new frame, including replacing a few components that attach differently to a 2012 frame vs the 2010 model, vs < $400 for Calfee to repair the top tube and paint it gray to match the rest of the bike. For an extra $75 they would have repainted the Trek logo on it along with a white stripe that was part of the original design (but was actually painted off-center), but I saw no reason to pay extra for that.
Chris: I damaged the chain stay near the chain rings when the chain got wedged between the two (from the bottom up, not the top down). There is a “chip” missing from the carbon, no hole and no crack that I can see. What are my options for repair?
Hey Chris! Sounds like you were laying down some serious watts. So, first, pat yourself on the back for being awesome. Next, pat your bike to see how the carbon’s doing. You might be just fine to just repair the cosmetic damage with a method like the one we wrote about here. To see if it’s really just cosmetic, or something more tear-inducing, I’ve laid out a few options for you below.
As an aside, if you’re having trouble with the chain jumping and causing this in the first place, you might want to check out a chain catcher as well as a your high-low limit screws. But that’s preaching you didn’t solicit.
Step 1: Check the Carbon’s Integrity
The easiest way (and probably the best idea) is to take your frame in to your LBS for your trusted mechanic’s advice. They should be able to tell you if the carbon is unsafe or the chip is merely cosmetic. The other good idea with this is that if your frame has any type of warranty, you’ll be able to find out through your LBS.
You can do a quick check yourself, though. Take a quarter and tap it gently around the chip–if you hear a difference in the sound (like a dullness) from other parts of the frame, then you’ll likely need to repair the carbon.
All in all, the only true way to be able to tell whether the carbon is structurally damaged is to have a repair shop do an ultrasound or something else as equally fancy on the frame.
Tell If Carbon Fiber Bike Cracked Leg
Step 2: Get That Chip Repaired Properly
If you do need to get that missing chip put back somehow, you’ll want to find a credible repair shop. In my experience, it’ll run you around $100-250, but that’s just a ballpark. You will find self-repair kits online, but without really knowing what you’re doing, these could be dangerous. Trust me, a little knowledge makes for nervous descents at 45mph.
Manage all of your InBody data with the Lookin'Body Web Cloud Database Management Solution. LB Web allows you to look at your data anywhere, anytime. Hit enter to search or ESC to close. Data Management Software. Lookin’Body 120; Choose another region or country. InBody Korea; InBody US; InBody Japan; InBody China; InBody India. Software for lookin' body shop. Products Data Management Software Lookin’Body120. Operating System: Windows XP SP3/Vista SP1/ Windows7(32bit/64bit)/ Windows8(32bit/64bit).
Carbon Fiber Road Bike
Be sure to go with some trusted repair companies too. Not just Blake’s Bestest Bike Repair (although Blake does true a mean wheel). Your LBS might also be able to recommend a good local repair shop. Barring that, here are two composite fixers that have years of experience and offer guarantees for their work: Ruckus Composites and Calfee Design. Grab a free quote or two online and go from there.
Tell If Carbon Fiber Bike Cracked Skin
Here’s Luck
Carbon Fiber Road Bike
Chances are, it’s probably not structural or a big deal at all. The key here–be safe. Get it checked by someone who’s properly qualified, and I’ll keep my fingers crossed for ya.