Is my carbon frame cracked

Brian B

When cleaning my bike today I noticed a 2inch line through the weave of the carbon in a semi-circle shape that I had not seen before on my down tube. Its under the lacquer and I cannot feel anything if I run my fingers over it. Whats really worrrying me its close to where I clamp the tube whilst taking my bikes to sportives.

It looks like a scratch but underneath the lacquer outer and I am worried that the frame has a crack. Is it possible to crack the carbon underneath the lacquer?

What should I do? I will take it to my LBS for adivce but I am worried they might sit on the fence. Or am I being worrying needlessly and just continue and keep an eye on the situation. The bike is only a year old with about 4mths summer riding.

redddraggon

I couldn't say without seeing a photo

cooper.michael1

'The bike is only a year old with about 4mths summer riding'

...it is the risk you take with carbon, it like an egg extremely strong in one direction, very weak in the other, one knock can break it regardless of how old it is.

Brian B

Tried to get a photo but can only see the spider like thin mark in strong sunlight and taking a photo of it does not show up. Have even tried to take in low light but cannot be seen or the flash comes on and it still cannot be seen.

I know that carbon is fragile in certain situations and prone to daamge as I lost my last frame when my rear derailer wrapped around and smashed my seat stay last summer. This frame was a replacement and only been ridden two months last year and two months this year.

Have tried to flex the frame and cannot see any change around the area concerned. I had to cycle through a section of loose chips yesterday that had been thrown down on the road and got a few pings with stones being thrown of the road. Wondering if it may be just scratched by these chips buts it the unknown and a chance that the frame might suddenly give that causing me concern.

Its a hard question to put to a forum but was wondering if anybody has saw damage due to clamping.

rake

i would never clamp carbon, especially on a bike rack bouncing about on the back of a car.
what does it sound like if you tap it, say with a finger nail.

redddraggon

From the information you give I'd say you shouldn't be worried. IMO It's highly unlikely that the composite could crack without damaging the clearcoat.

I'd continue riding the frame and monitor the "crack" and if it grows be worried.

If you are really worried, it'd probably be best to get it checked by someone trustworthy you know someone like an engineer maybe, I'd probably not get the LBS to check it, but yours might be staffed by knowledgeable guys.

Buckled_Rims

It might be a bit too simple a test but have you tried pinging it with your fingernail to see if it changes sound? A thin crack should dull the sound faintly.

nicensleazy

It may well just be the way the outter caron wrap has been cut and applied. I was looking at a brand new Dogma the otherday and it too had these marks within the outter carbon wrap. However, if you are unsure, take it back to your dealer. Saying that, most people in the bike shop really wouldn't know away!

pilot_pete

Take a look at this carbon fibre bike repair specialist's website faqs http://www.carboncyclerepairs.co.uk/index.php?FAQ Third question from the bottom. Seems he probably has a good idea about these things as he gets sent them to repair on a regular basis.......

Perhaps send him some close up shots which show your area of concern. He may be able to offer some more comprehensive advice than an lbs? FYI my carbon fibre Pinarello frame has what look like 'join lines' in the unpainted carbon fibre areas.

Hope this helps

PP

rake

my bordmans like a patchwork quilt. its just the many different pieces that are layed in the mold. there are many overlapping layers, just how there built. probably its just the cosmetic layer if it has one, it hard to put one complete layer over such a shape of a bike.

Brian B

Thanks for all replies. Still woried but going to keep riding and monitor the 'crack'. Going to take it to the shop where I got as the main mechanic(who is also pretty handy when it comes to racing) will give sound advice I think. If in doubt I may send it to get checked/repaired.

Anybody on here had there frame repaired and if so where?

giant_man

Sounds like just the paint, carbon isn't that delicate Brian B, hard to determine without a picture.

Stuartyboy

Hi Brian B,

Although I cant offer any advice on your problem it would seem that I have a cracked carbon frame. I was just googling my concern about my Giant Rapid Advanced. I recently converted it to a dropbar and after a weekend off riding I noticed a 2 inch crack along the top tube. Running a finger across it and the lacquer was definitely cracked. Gutted.

Took it to my LBS and it has been sent back to Giant last week to look at. Its not even a year old

Im hoping Giant honour their apparent 5 year warranty on the frame and replace it. Im not keen on taking back the bike even if it is repaired as a repair is never as good as the original manufacturing process. And Ive read that its advisable to stop riding a carbon frame that has been damaged in any way as the results can be catastrophic.
Good luck with your issue and I hope its resolved

Regards
Stu

Brian B

Nightmare just rode 30miles today and the 'crack' has doubled in length but still cannot feel anything by if you run your hand over the area. Have contacted carbon cycle repair and got an great email back from them. My LBS has dealt with them in the past and cant praise them enough.

New plan is to take take to my LBS for advice but think will get it stripped and ship it to carbon cycle repairs. They said they will inspect and repair if necessary. Not great news but much better than buying a new frame. I know the pain of that last year when I totalled my storck scenario 0.9 when my back derailer went into the back wheel and took out the wheel and the back stay.

cougie

Ive had my carbon Giant clamped on roof racks many times - no issues. I always use padding round the tube though.

Pro teams use clamps on their stands too - albeit with padding there too.

dcl10

If it is actually growing larger then I would suspect it is likely a crack. If it’s small enough I don’t think you would notice any flex in the frame. I hade some carbon bars that broke near the top of the dropout were almost the entire front was knocked out, and there was probably a 20% or so increase in flex with maybe only 60% still structurally intact. I do believe almost all manufacturer warranties are void if you clamp the frame, run it on trainers etc. so obviously play stupid with any warranty claim. When you clamp opposite the direction of the fibers, you basically just have the strength of the epoxy binder itself, which is not much, so I would recommend against doing that any further.

Brian B

I sent my bike away to "cycle carbon repairs" but they reckoned it nowt to worry about. I am just going to keep riding and monitor. LBS and "cycle carbon repairs" think its just cosmetic.

There is still the element of doubt but at least I have it insured incase its does get totalled.

cooper.michael1

Glad it did'nt turn out to be terminal, sounds like you've had bad luck with carbon....next time buy titanium and you wont have to worry about it!

Smokin Joe

cooper.michael1 wrote:

Glad it did'nt turn out to be terminal, sounds like you've had bad luck with carbon....next time buy titanium and you want have to worry about it!

I've seen more than one thread on here featuring cracked Ti frames.

cooper.michael1

Well yeah indeed, and Alu and Steel...but if your rear mech hits the rear wheel of a metal bike it is unlikely to rip it in two, as Brian described.