Minor Crack to Carbon Wheel

coL

Was changing my rear wheel (tubular) the other day when I noticed a small crack in the bead. Its hard to take a pic but the attached should give an idea of size and location.

What does everyone think? Is it likely to affect the structural integrity/strength of the wheel? Can I keep cycling on it and is it repairable?

benneca1

Is the issue keeping you awake very early to be posting.

On a serious note is there such a thing as a minor crack in a wheel consequencez of failure could be pretty high.
?

Miklos

I wouldn't be riding on it, but certainly explore having it repaired. Try someone like Custom Composites.

coL

benneca1 wrote: »

Is the issue keeping you awake very early to be posting.

On a serious note is there such a thing as a minor crack in a wheel consequencez of failure could be pretty high.
?

In a different time zone so was well into the morning here when I posted that.

The crack is on the bead and not in the main body of the rim so don't see why it would cause any structural issues. Given the location the chance of failure is minimal. All I can see is that it might pinch the tyre but as it's a tubular that shouldn't be a problem. Wanted to see if there was some aspect I wasn't considering

coL

Miklos wrote: »

I wouldn't be riding on it, but certainly explore having it repaired. Try someone like Custom Composites.

Thanks will give them a try

koutoubia

FWIW I have a carbon rear tubular wheel. The bracket track literally start Ed to fall apart. Still rode it for a few hundred kms while I was waiting on a new wheel to be built up. Had no issues but never used the back brake to heavily.
Tubular rims have a different ' structure' (if that's the right word ) to clincher rims so a catastrophic failure is less likely. What I mean is the rim can crack and you won't get a blow out .

Cee-Jay-Cee

Does the crack go all the way through, ie can you see it in the other side? It looks very minor however it's difficult to tell from a picture. Is there a clear coat on the carbon? Can you feel the crack with your finger nail or is under a clear coat?

coL

Cee-Jay-Cee wrote: »

Does the crack go all the way through, ie can you see it in the other side? It looks very minor however it's difficult to tell from a picture. Is there a clear coat on the carbon? Can you feel the crack with your finger nail or is under a clear coat?

Part of the crack goes all the way through and can be seen on the other side of the bead. I can feel the crack with my finger.

coL

koutoubia wrote: »

FWIW I have a carbon rear tubular wheel. The bracket track literally start Ed to fall apart. Still rode it for a few hundred kms while I was waiting on a new wheel to be built up. Had no issues but never used the back brake to heavily.
Tubular rims have a different ' structure' (if that's the right word ) to clincher rims so a catastrophic failure is less likely. What I mean is the rim can crack and you won't get a blow out .

My thinking is that as the crack is on the bead and not the main section of the wheel there shouldn't be any structural issues and minimal flex. Given that tubular tyres are pretty robust especially where they are fixed to the wheel the chances of a pinch flat from this crack is minimal.

Probably need to speak to someone familiar with carbon wheels and the loads involved.

Eamonnator

coL wrote: »

My thinking is that as the crack is on the bead and not the main section of the wheel there shouldn't be any structural issues and minimal flex. Given that tubular tyres are pretty robust especially where they are fixed to the wheel the chances of a pinch flat from this crack is minimal.

Probably need to speak to someone familiar with carbon wheels and the loads involved.

At what stage does a crack become a break?

I'm not a structural engineer, but I think there has to be a flaw in your thinking.
Suppose you were unlucky enough to hit a hole, just at the point, where the crack is, are you happy enough to rely on the structural integrity of the wheel?
I'm sure, I wouldn't be!

koutoubia

Now if the crack is going all the way through then it's a different story. Your carbon had ' failed' .The bead is probably the weakest point. If it were me and the hub is still good I would get a new rim and get it rebuilt.
My issue was on the brake track and it was just the carbon breaking up. But there is still carbon there. If it got to the point that I could see through the carbon then it's a different game altogether.

Kaisr Sose

coL wrote: »

My thinking is that as the crack is on the bead and not the main section of the wheel there shouldn't be any structural issues and minimal flex. Given that tubular tyres are pretty robust especially where they are fixed to the wheel the chances of a pinch flat from this crack is minimal.

Probably need to speak to someone familiar with carbon wheels and the loads involved.

Edit:
Had not seen Eamonnators comment.

I would not be so confident. Hit anything at this point and the energy will be absorbed fully here = possible sudden and cathostrophic failure of the rim. Alternatively, crack creeps further and further with use over time leading to the same result.

Do you won't to risk this at 60kph or more?

coL

I am no expert on where the loads are on a bike wheel but I was of the impression that the loads on the bead of a tubular tyre in particular were minimal enough. I always expected the main wall of the deep section of the wheel to be the area of greatest load was sustained.

I am lucky where I am at the moment as there are no potholes but as I am moving back to Ireland shortly the amount of potholes I encounter is likely to increase.

What I have gathered from all the comments though is the possibility of the crack spreading, in which case it would be dangerous to continue using it.

Thanks for all the help.