Carbon fork crack - is it just the surface?

stanko

I noticed some damage on my carbon fork after my last ride (photo attached). I don't have much experience with carbon (I rode this fork only for about 2000miles) so I wanted to ask if this looks like a surface "scratch" (maybe from a small stone) or like a fork that needs to be replaced? I tried to bend the fork a bit and to lean on the handlebars with all my weight and I did not hear any suspicious cracking sounds.

In the next day i will probably get it to the local bike shop to get it checked out but i wanted also to hear your opinions before I do that.

Thanks!

Bozman

Probably just the clear coat. Going to the lbs will give you piece of mind.

Monty Dog

Looks like some impact damage

stanko

its on the inside of the fork and that's why i am wondering where it came from. maybe a rock hit it but i am not 100% sure. sometimes i ride on some rough roads and maybe the potholes stressed it too much?

i will definitely get it to the lbs and if they think i should replace it, i will do so...

Monty Dog

Paint is brittle but carbon is a lot tougher - looks like something narrow has struck the fork e.g. sharp stone rather than it being due to ridden on rough roads IMO

stanko

thanks! if i keep the fork i will inspect it regularly and ride slowly on the next ride or two and check if the damaged area changes...

Bar Shaker

Paint on bikes has a plasticiser in it, so it doesn't crack. That is not 'paint only' cracking.

This is damage to the structure below the paint and I wouldn't ride until you are 100% certain that the fork isn't damaged. Imagine pulling on a lot of front brake or hitting a speed bump, on a fast downhill section!!

From the photo, I suspect the carbon is damaged and the crack would get worse very quickly if subject to stress loading.

term1te

Bar Shaker wrote:

Paint on bikes has a plasticiser in it, so it doesn't crack. That is not 'paint only' cracking.

This is damage to the structure below the paint and I wouldn't ride until you are 100% certain that the fork isn't damaged. Imagine pulling on a lot of front brake or hitting a speed bump, on a fast downhill section!!

From the photo, I suspect the carbon is damaged and the crack would get worse very quickly if subject to stress loading.

If the paint is "flexible" and the carbon brittle, why doesn't the paint hide the damage to the carbon, rather than show it up here? As someone who has a set of aluminium forks let go on me, I'm quite cautious about damage on my bike, but as others have said, this looks more cosmetic to me, but best get someone more knowledgeable to have a look

Bar Shaker

When you say 'cosmetic damage', the paint is microns thick and is chemically bonded to the carbon below it. How would this paint be so damaged if the carbon below it wasn't? If you look on the right hand side, you can see how the stress steps across in small overlapping lines. This would indicate a major overload of the structure beneath, rather than a scrape. The bit along the bottom show multiple crack lines, from repeated over stressing.

If you pull the fork away from the damaged area, you may even see it move.