Carbon Fiber Cuts

KM5BH said:

Well I realize this wasn't the smartest thing I have ever done, but I let my son ride the new bike and he managed to throw the chain before he got a half mile from the house. He wrapped it up pretty good and scored the frame in several places.

It all depends on how deep the damage goes, and it's near-impossible to diagnose this over the internet. Your best bet is to take the frame to a good bicycle store for an assessment, ideally one that is familiar with your brand of frame.

Dietmar said:

It all depends on how deep the damage goes, and it's near-impossible to diagnose this over the internet. Your best bet is to take the frame to a good bicycle store for an assessment, ideally one that is familiar with your brand of frame.

I just got off the phone with the dealer here in Houston. He said I should bring it by this weekend. Dang It! It is a week old today. That kid of mine is a walking advertisement for birth control. :eek:

Lewis

KM5BH said:

So what do you think? Just ride it or worry about it?

Hi there

You could post a photo

regards

KM5BH said:

I just got off the phone with the dealer here in Houston. He said I should bring it by this weekend. Dang It! It is a week old today. That kid of mine is a walking advertisement for birth control.

Uhmm, may I remind you that you had posted before that "Well I realize this wasn't the smartest thing I have ever done[...]"? After all, it was you who let your son, who is obviously less than experienced, ride that brand new bike? I'm just sayin... 😎

Seriously, I know how you feel, though. Stuff happens, and it may well not be as bad as it seems right now. Good luck!

P.S.: By the way, maybe it wasn't even your son's fault; it could be that the place you bought it from did not properly adjust the front derailleur, in which case you could argue the damage was ultimately their fault. Just a thought.

Dietmar said:

Uhmm, may I remind you that you had posted before that "Well I realize this wasn't the smartest thing I have ever done[...]"? After all, it was you who let your son, who is obviously less than experienced, ride that brand new bike? I'm just sayin... 😎

Seriously, I know how you feel, though. Stuff happens, and it may well not be as bad as it seems right now. Good luck!

P.S.: By the way, maybe it wasn't even your son's fault; it could be that the place you bought it from did not properly adjust the front derailleur, in which case you could argue the damage was ultimately their fault. Just a thought.

That is a thought, but as you say it is my fault. I knew better but didn't want to hurt his feelings. My bad!

I'll post a pic. The scratches are deep enough that I have no trouble getting fingernail down there.

steve said:

Hi there

You could post a photo

regards

I just did.

KM5BH said:

That is a thought, but as you say it is my fault. I knew better but didn't want to hurt his feelings. My bad!

I'll post a pic. The scratches are deep enough that I have no trouble getting fingernail down there.

That looks pretty nasty :eek: I don't know enough about frames to know if its terminal or not, getting it looked at if a great idea.

cheers

KM5BH said:

That is a thought, but as you say it is my fault. I knew better but didn't want to hurt his feelings. My bad!

I'll post a pic. The scratches are deep enough that I have no trouble getting fingernail down there.

Wow! Why didn't he stop pedaling as soon as the chain came off?!?

Regardless, if he had to scratch the frame ANYWHERE, the BB shell is probably the most robust place to have GOUGED it because of the alloy sleeve which is inside the shell ... small consolation, eh?

So, FWIW, the damage could have been in a much worse location on the frame.

KM5BH said:

Houston.

let me know if you wanna hook up and ride.

preston

Agree with alfeng. Assuming your bb has a threaded alloy shell, should be no problem. Even if the bb shell had been significantly weakened, it's not a safety issue that will put you on the ground (ie, not like deep gouges in your front fork).

You've just discovered one of the few disadvantages to a CFRP frame, ie the "plastic" part. As strong and light as these frames are, they don't tolerate rough treatment very well.

dhk2 said:

Agree with alfeng. Assuming your bb has a threaded alloy shell, should be no problem. Even if the bb shell had been significantly weakened, it's not a safety issue that will put you on the ground (ie, not like deep gouges in your front fork).

You've just discovered one of the few disadvantages to a CFRP frame, ie the "plastic" part. As strong and light as these frames are, they don't tolerate rough treatment very well.

I was worried about it being fragile when I bought it. But I thought I could handle it. It hurts to look at it on new bike, but I don't think I have hurt the structual integrity at this point. I am more concern about any delamination over time from moisture. It is extremely humid here and my thoughts and concern were more to problems over time with water entering the carbon fiber laminates.

Lewis

I agree with the others; the part you have damaged is by far the most sturdy section of the frame. Also, practically all modern carbon frames have one finishing layer of carbon weave on top, which is mostly cosmetic. Even if that is disrupted, the integrity of the load-bearing structure should not be compromised. You should still have it looked at, but chances are you can keep riding that frame.

dhk2 said:

You've just discovered one of the few disadvantages to a CFRP frame, ie the "plastic" part. As strong and light as these frames are, they don't tolerate rough treatment very well.

Yeah, you kind of have to treat these things like raw eggs with respect to anything other than the loads they were designed for. You can ride them over cobblestone at 30mph no problem, but you can destroy a frame simply by having it fall over and hit something in some unfortunate way, or by squeezing one of the main triangle tubes really hard with your hand.

You could get some auto clear coat or paint to seal the area against moisture, but I wouldn't worry about the looks at all. If you use your bike, this stuff is going to happen. My aluminum frame has the paint rubbed off there due to a similar chain dropping; suspect many others do as well. Besides, nobody really sees it there except the rider🙂

I took the bike to the dealer yesterday and he told me it would be fine as I have been told here. He also asked why I let anyone ride my new bicycle. ;-))

It rides great by the way.

Lewis