Crack in carbon fibre of just a chip?

245

Hi,

I noticed this on the top tube of my bike earlier. Is it just a knock from someone careless in the bike shed in work or is it a crack? I can't think why the top tube would be particularly stressed but the carbon fibre does sound particularly thin there.

Caroline_ie

Use the "coin test" to check for damage to underlying carbon layers.

Tap on the tube with a coin in the area and compare it with the sound on other tubes, in surrounding areas, and on the opposite side.

AstraMonti

This looks more than a chip to me, but its so much a picture can tell you. Get it to a shop you trust.

DonVincenzo

Came across a "chip" in my Storck carbon frame recently (near bottom bracket area). Slightly bigger that your photo - but maybe mine started that size. Had to ship it over to the manufacturer in Germany to get checked (as I bought it over there). Am glad I did.

I was completely gutted when Storck told me it was a crack & the frame couldn't be saved. But when I thought about it, I was lucky it hadn't collapsed underneath me. I was gona take it out for a spin in the mountains the day after I spotted the crack. Very lucky I didn't.

I'd recommend you go back to your retailer & manufacturer to get the frame checked.

cassette50

Sorry to derail the thread but how common is it for carbon frames to fail?

Craig06

From years of kayaking with carbon paddles that looks like the start of a weakness. A bit of force and it could fail instantly. Get it checked definitely.

245

Thanks for the responses. The coin test was inconclusive - the entire top tube sounds different to the other tubes (less solid) but its a different shape and possibly a different thickness to the others.

I guess its back to the shop for a closer look.

@cassette50 - google shows a lot of discussion about carbon failure but its the kind of area where people only discuss problems so we don't tend to hear about the frames that stay intact.

FWIW I have a 1989 Giant CFR1 which is crack free and has been regularly used.

cdaly_

Pic looks bad to me. The fact that there are different colours of crack with what look like fresh stress lines heading off to the right looks to me like something serious. Also the vertical black bit looks like a break. I would expect to be able to depress that with my thumb...

245

Thanks - a closer look today shows another area of cracking at the base of the top tube in the same area. I've done maybe 1200km on the bike since I bought it so this is disappointing to say the least....

shaka

245 wrote: »

Thanks - a closer look today shows another area of cracking at the base of the top tube in the same area. I've done maybe 1200km on the bike since I bought it so this is disappointing to say the least....

1200 km is nothing, surely covered by manufacturer?

C3PO

Very strange place for a crack to develop if the bike hasn't had an impact there. Is there any chance that something got dropped on the top tube? What make is the bike?

245

I bought it last September so its still be in warranty - I'll bring it back tomorrow as its the first time that I can get back to the shop. I can be definite that nothing dropped on the top tube. I'm fairly sure that I noticed the mark more or less as soon as it appeared as its hard to miss and the bike was unmarked before that.

Its a Lapierre Sensium 100.

Mycroft H

Get yourself back to the shop. Get them to deal with it.

245

An update: the bike shop have submitted a warranty claim with Lapierre and offered me a lend of a bike to keep me going for the week or two that it'll take to get a decision from the manufacturer. So far so good...

Morrisseeee

Fcek, just when I'm confident & thinking about buying a carbon frame, you show me this.............confidence level is pretty low again

Mycroft H

245 wrote: »

An update: the bike shop have submitted a warranty claim with Lapierre and offered me a lend of a bike to keep me going for the week or two that it'll take to get a decision from the manufacturer. So far so good...

Try not get dragged down the route of the manufacturer warrenty, your contract is with the shop, not with the manufacturer

shaka

Thought frame warranty is with manufacturer ?

D20903

The frame is impact damaged & cracked.

245

D20903 wrote: »

The frame is impact damaged & cracked.

Thing is - there was no impact. I was thinking back over this again. The last time the bike was in work was Thursday. I used it on Thursday evening going home, I worked from home on Friday and got a 30km spin first thing, again on Saturday and again on Sunday. It was the first thing I noticed when I finished my spin on Sunday morning and I'm fairly sure that it wasn't there when I first took the bike out then. Its an 'as new' bike with no marks/scratches so I'm certain that the marks weren't apparent until after my ride on Sunday morning. The paint has chipped at the point of the main cracking but that's from flexing, not from impact.

route66

D20903 wrote: »

The frame is impact damaged & cracked.

How do you know?

245

Thought I should update this to complete the thread. Lapierre took their time making a decision on the frame so Cycle Superstore decided to replace the bike with a new one. I think that its worth naming them so that they get credit for good service and customer support.

Finnt

Fair play to them, only right in a way but still fair play!

Konkers

yeah that's great, for you and them.

Still interested to hear the decision from Lapierre when you get it. Own a carbon bike and if you don't know how this happened it would be good to hear the manufacturers explanation.