CrossChain

I jinked this evening and tapped my riding buddies front wheel....down he went at 18-20mph. Aside from his shorts and hip, a fork blade and a portion of his top tube got seriously scuffed. I saw no cracks or penetration. Question: Though an accident, I feel badly.......I'm unfamiliar with cf-- have I shortened the life of his frame or begun a process leading to a future frame failure?

fiver

Internal stress is very hard to detect, but if there is any bulging, chipping, or alignment issues, just make sure your friend mentions is to the mechanics the next few times he goes in for a tuneup.

Deanster04

Your friend was too close...it wasn't your problem...unless you braked suddenly and swerved. Tell him a little prayer before each ride might help.

stonecrd

You can only protect your front wheel, as long as you didn't brake or slow quickly there is nothing you could do about this. Inspect the frame closely, but CF doesn't really flex and fatigue it fails. So if you don't see any penetration of of the fibers or unusual flexing due to a crack the frame is most likely Ok. Trek use to have a film clip on their website on how to inspect a CF frame, you may want to see if it is still there.

capwater

Be very careful riding that frame, if you can't check it out get it to someone who can.

I crashed a Giant TCR in a crit last spring. I inspected that sucker completely, only finding a very small chip in the top tube's clearcoat. The handlebar had smacked it when my wheel got taken out by a downed rider. Aside from a broken bone in my wrist and a bruised shoulder I was stoked my bike was fine. So I ride it for two more weeks then go to clean it after a ride only to discover two 1 inch long cracks in the top tube. Bye bye frame.

Deanster04

Steel isn't dead it is just sleeping until the cycling public comes to its senses.
I just crashed heavily on my new Mondonico Daimond Extra Columbus Neuron tubeset with an older Pinarello steel fork. Had is checked out and needed the derailluer hanger coldset. No worries...and the bike is 17.8 lbs. There are some good and light steel frames still being built.

MyBikeGotStolen

Id tell your friend to get a bike thats not "plastic"

stonecrd

Yeah, an AL or Steel frame never gets damaged in a crash

waterrockets 

While I get your point on careful and repeated inspection, Calfee could probably repair that frame for cheap (much less than replacing a top tube on a steel bike).

Hobartlemagne 

Ride Ti. The good ones are very light, and you can be confident about crash survival.

MyBikeGotStolen

its usually alot more obvious when a steel or AL frame is damaged. I just look at it as a safey aspect.

Gus Riley

Can't get more obvious than this. Carbon frame.

A friend of mine was broadsided by a car at 40mph. He was not seriously injured. Wow!

wroomwroomoops

Jeez... it seems I'll never regret never having or wanting to have any CF part on my bikes, let alone the frame... There just never seems to be anything appealing about it, and a whole lot of appaling against.


EDIT: seriously, what's the appeal of CF? As someone already said, there are pretty light steel frames, not to speak of Ti. Is it the 300-400g less of weight? Take a dump and there you go - instant CF weight class you and your bike together.
I guess it's the higher price. The stupid "it's expensive, it's GOTTA be good."-mentality. Followed by cognitive dissonance "I invested too much money into this thing, I must defend it at all costs - this thing IS good otherwise I feel stupid".

jleslie

In aerospace, there is actually a "coin tap" test for damaged composite structure. Take a quarter or larger coin and gently tap the area around the scuffs. It should all sound the same. If it makes a different sound anywhere near the damage, you could have internal delaminations that might cause failure.

I love my steel Serotta...

Jim

Boss Moniker

You want a serious answer? Well, there really isn't too much of an advantage for CF, but the slight advantage appeals to some. People tend to believe that "road vibrations" are reduced with CF, although a well made aluminum frame can have the same effect. I think it's supposed to be stiffer, or at least the molding process can vary the stiffness around the frame, hence the ubiquitous phrase "laterally stiff yet vertically compliant". The moldabality of the material also helps make parts more aerodynamic, which really doesn't do much anyway because 90% of drag comes from the rider's body. But it is more attractive. And on average, carbon fiber frames can be easily made more lightweight than other materials.

Will 80% of riders notice or appreciate the difference? No, but certain time trialists and triathletes think that spending the $$$$ on lighter and more aero gear to improve their times is easier than training. Not to mention weekend warriors, . That said, I think CF has its place in cycling. A CF fork on a metal frame might save the rest of the frame in a crash because it fails quicker. This is somewhat important if your metal frame is very valuable. Having a CF fork and stem makes a big difference on certain aluminum bikes that ride harshly. I know, I ride an old Al C'dale R500 that has straight seatstays, non-ovalized tubes, and an Al fork. Can I still ride it? Yes, but I tend to think a CF fork would make it at least slightly more comfortable. Also, if you want to build an extremely stiff frame, as are valued in track racing, CF is a decent choice because you can get thick tube walls without increasing weight too much.

Just some thoughts

wroomwroomoops

Interesting points. But this one I quote, is kinda... funny. A carbon fork is better because it will fail quicker? A big WTF to that. I mean, if your front wheel goes, you go - down. And having your front fork fail kinda affects the position of the front wheel...

Regarding lightness: as I already said, visit the loo and there goes the difference in weight.


That said, I can aprecciate the things you discuss, as a point of view CF cyclists might have.


By the way, I really do notice the (only) Al-framed bike I have (now somewhat dismantled) rides more harshly than any of my steel framed bikes. Yes, I know tyres make the biggest difference, but I'm talking at parity of tyres.

MyBikeGotStolen

Maybe they are made for riders who like to ride around having to poo and dont want to carry the extra weight of the poo it self.

wroomwroomoops

Not quite sure what you mean; are you saying they're basically anal-retentive?

MyBikeGotStolen

Just saying that for thousands of extra dollars, you dont even have to make sure you poo before you ride your bike to loss an extra pound!

Boss Moniker

What I meant was there's this certain point where your going to fall anyway in an accident.. in fact, it happens pretty easily when on a bike. Now if there's an impact, wouldn't you rather it destroy just your fork rather than your fork and frame? I think you read the word "fail" as in a JRA spontaneous fail, which does happen much more often to CF than to anything else, and it is a fault that I forgot to address. But that's not what I meant.


Weight savings.. yeah, it's an insignificant difference, but it's still a difference and this is important to some people.

maddyfish

Time for a new frame.
My opinion-CF is a limited use racing product. You use it, then chuck it. It's time to chuck it.

wroomwroomoops

Well, I get what you say but I still have a bit of trouble wrapping my mind around it. I don't mind if my frame has a higher chance to be fubared in such a catastrophic impact, as long as I can trust my fork not to buckle under me, in all riding conditions.

What is a JRA fail?

Carusoswi

My LBS friend rode with Fred Landis at a charity event a while back . . . had a chance to chat with him. One comment that impressed my LBS friend was that FL says that he isn't particular or meticulously insistent on how his mechanics set up his bike . . . says seat/bar adjustments don't really make much difference to him and he probably wouldn't notice changes from one ride to the next.

I feel the same way about frames. Five minutes on most any frame, and that's the bike that I'm riding, and I can ride it all day. I'm no pro, but I do a lot of riding.

My old Schwinn was steel, my C'dale was aluminum, my Giant TCR is CF.

The C'dale frame was crumpled under the front wheels of a car. It's just a guess, but, in my mind, neither of the other two bikes would have crumpled like that. CF is extremely strong. If it doesn't break, then, I"m not too worried about it failing spontaneously. I think that characteristic of CF is over blown for practical purposes.

For all the discussions here about CF's propensity to fail spontaneously, how many can relate from actual experience, first hand? I doubt many. I'm not talking about failure in a crash. I'm talking about a frame that fails suddenly with previous damange limited to a scratch or some cracks in the clear coat.

In every day life for every day riders, it just isn't a problem.

We were chasing down some clicks on my TCR at the LBS. During the diagnostics, the mechanic put my BB under a lot of stress. I was surprised (and a bit stressed) as I watched how much flex there was in that frame (one of the criticisms pros voice over my particular TCR model), but nothing cracked.

I ride that bike with confidence. Have taken a couple of 25 mph falls (didn't crash into anything but the road). Everything continues to feel tight and solid.

If the tumble taken by the OP's riding partner didn't involve striking anything stationary except for the road, I would not be too concerned about some scratches or cracks in the finish.

As for fascination with CF, it does allow for some added design capabilities, it is comparatively light, for those of us who like the way it looks, then, it looks cool, it's in, it's comfy to ride (but all bikes seem that way to me), it won't rust, it works. So, without knocking any other tried/true materials, I see no reason to knock CF.

Caruso

stonecrd

If you want to read a bit about CF, Calfee has a nice whitepaper at

https://www.calfeedesign.com/whitepaper1.htm

Now since they make CF bikes I'm sure people will assume this is biased but you can make up your own mind. As waterrockets says if you do crash your CF someone like Calfee can repair it as good as new for a few hundred dollars.

Disclaimer: I ride a CF frame (also have ridden AL & Steel) and I love it and have no fear of failure.

George

Yes I read that article and many more about CF as well as most RAAM riders use the same bike from the shop like we do. I'm not worried about it one bit. I've seen so many pictures of bikes after wrecks, that makes you wonder how someone could live through. I rode motorcycles for years as well and I don't care what they are made out of they all look pretty bad.

To get back to the OPs question, yes it can be repaired. I worked on plastic boats for years and some of the work I've seen being done on them after being taken off rocks is amazing. You wouldn't believe how much a mast 100 feet high flexes and they sail them around the world. Yes some do fail, but that is very rare. I think the pounding that race bikes, boats made of CF, or any other material would fail under those conditions. I'm glad those people tested them before we got it, but again, I'm not worried about it and if a rider is worried about it they should pick a different bike.