Signs of carbon frame breakage

Northridge

I fear that my Giant NRS composite frame has finally called it a day: after 4 years of offroad and 3 street, it releases increasingly loud cracking sounds and I see what looks like delamination - and I think - cracks around the top of the BB.
People I showed it too say its only superficial but here in the NE of Brasil I havent yet found anybody with carbon experience.
Whilst ready to accept the inevitable I would like to know if it really is broken and unusable.
Anybody have experience o carbon failing and know what to look for? Anyone have pictures or know where I can find some to compare with what I see.?
Thanks

02gf74

It is fixable but really depends on how nice you want it to look. The frames would have gone through the proper manufacturing process - don't know the detials - but may invole and oven and vacuum forming.

You can make carbon fibre parts using matting and resin that can look just as good, with some practise, although will not be a strong as if they were made the proper way, but then you just use an extra layer or too so sdacrifice a bit of weight.

So by laying on mat and resin, you can build up the bottom bracket area yourself but it will not look too nice.

Someone on the forums is a descritpion of how to fix a broken tube - different and less complex situation to yours - but the results are much bettter than you would expect.

Northridge

Thanks for the encouraging news. Being the BB aesthetics are hardly a problem (Trek didnt seem to mind ugly when they overbuilt the OCLV hardtail with that yoke big enough to have a picnic on) and would allow me to over-repair it as long as I maintained the clearances.

But all that is moot unless I find someone here to do it: the only place I can think of to look is the motor racing community who prolly have experience of carbon: in the bike community by chance I know the only guy who would have some experience: he mechanics the pro triathletes with their Kuotas and Cervelós and Specialized - but I cant locate him.

The bike people I showed it to are on a tremendously steep learning curve regards bike technology: suspension and disc bikes are still relatively new, having come from selling and repairing supermarket delivery bikes to authorised Cannondale dealer in 4 years. They sell the gear but dont yet understand it. They have no experience of carbon - dont yet know how the frames are made. All that being said, they have years in the trade and I respect their experience, and golly can they sell Cannondales straight out the door.
Tthey said its just the resin coating flaking: what I feel as a crack is the "un-level" of the bit thats falked off.

Showed it to a 30 years in the business car-nut with a tune-up and body-shop specializing in old imports: he said it was the resin flaking off.

If it is the resin - could that not be a sign of deeper, as yet unseen malaise? Its flaking for a reason.

Over the last six months the bike has given off ever-loudening cracks - sharp, dry - and as time went on the tone changed, became lower, sturdier, more - structural. Day before I saw the cracks it sounded like a gunshot: people I was with turned their heads - honestly. For a long time I thought it was the seatpin too short in the frame and didnt think to look at the BB cos I couldn´t feel anything wrong.

Anyway - sorry to go on, haven´t chatted about bikes in a while - thanks again for your interest.

ride_whenever

Whereabouts are you, if there is a rowing club then they might know a local boatman with experience in carbon and carbon repairs...

jakeeeeeee

some pics might help ?!

02gf74

have a look here about DIY carbon repair.

http://activecycles.co.uk/2010/03/07/ca ... me-repair/

google for carbonmods (think it is them) that have a video showing how to make carbon fibre parts (for kit cars).

in theory, you could slap on extra carbon fibre on top of the BB your self or to do it propely, find someone who works with the stuff but you need to decide how much that would cost compared to another frame.

Northridge

I dont know that I could show it in a picture - to be honest it really is very slight and you feel it more than you see it. I dont know what carbon breaking looks like.

Here´s a possible cause for all the cracking noises - and for the looseness I had previously felt: one of the bearings holding the rocker plates to the frame is completely corroded: there remains an outer ring, some vaguely round things and an inner ring - and you can see daylight through it.
This gives several mm of play on that side - and play on the other side too, which would mean that the whole bike was constantly out of whack and every time I mounted it would settle into a new position.
Or am I grasping at straws here?

I am in NE Brasil. No rowing club here but there are car racers.

Devastazione

man...I'm regretting the day I've spent so much cash on carbon fiber bikes.

My Lapierre X control makes a weird "crack" and "squeak" noise in the bottom bracket area since the very first day I've brought it home. In a year span I've inspected it very closely multiple times even with a magnifier and there is no sign of crack whatsoever but for a bike that carries a 5600 Euro price tag it really SUCKS !! I actually expect the damn frame to split open anyday,that would be oh so funny... :x :x :x :x


Anyway,best of luck to you in fixing your precious bike

ride_whenever

Devastazione it's bound to be something more obvious, like chainrings needing a touch of grease round the bolts, or a sticky pedal.

UpTheWall

Afternoon,

Aye - cracking noises often come from my bike if the seat is not tightened on my seatpost properly, or indeed seatpost clamp not tight enough.

That said, if you can see visible cracks around yoru bottom bracket I'd getoff the bike quickly. If it cracks on the road.....

I've had a specialized allez for over 5 years. I spotted a crack a couple of months ago at the top of the down tube (not on the join), so stopped riding it.

I got my LBS to send it back to Spesh and they replaced the frame.

(As long as there's no evidence of a crash they're happy to replace them.)

I guess they don't want the bad pubilcity of a frame breaking and hurting someone.

And as I've had 3 specialized bikes they are still doing well out of me....

Si

Jack 123

I would contact Giant after you tear the bike down and lube and clean it make sure its the frame and yeah normally they will replace it. The bb can creak and the fork can creak and the stem and the seat post and the casette ext. Plus its tricky trying to find the noise.

Northridge

I would love a new frame - an Anthem Advanced would do nicely - but the original importer in Portugal no longer exists and I am now in Brasil.
Even if it were possible to convince Giant Spain to replace a 7 year old "Portugues" frame I would end up paying so much for transport and then taxes (thievery doesnt start in the slums here, it starts in the Govt and all its offices) to make it painful.

Are those cracks in the carbon or just one layer of resin coating flaking off? The consensus is flaking.
I have ordered all the bearings and bushing and bobnobs to rebuild the shock and rear end - one of the bearings was crumbled almost to powder - and see how the bike rides and sounds. As unfortunately I no longer have access to trails the bike will never again be ridden properly, so hopefully it will hold together.

Thank you for all your comments and advice.