Does carbon fibre creak?

[AndyHenderson]

I went over a nasty pothole recently - double puncture and a torn tyre. Somehow managed to stay upright.

Ever since I've had a continuous creak when pedalling. I can reproduce the creak by pressing down alternately on the left and right pedals. The creak seems to be coming from the down tube.

Now, I know there are plenty of reasons why a crankset can creak. I have a SRAM Force 1, and they're apparently notorious for creaking. I also know that sound can 'travel'. My concern, however, is there might be damage to the down tube and that the pedals are exerting a twisting action on it which results in the creak and might eventually cause it to fail. There's no cracks that I can see. Is it possible for carbon fibre to creak in this way?

Andy

[iandriver]

Creaking carbon bikes are the stuff of legend for creaking. If you've had the wheels off, try your QRs first if you've got them. Could be the seat post of anything, that's the hard part, finding it.

[roubaixtuesday]

I went over a nasty pothole recently - double puncture and a torn tyre. Somehow managed to stay upright.

Ever since I've had a continuous creak when pedalling. I can reproduce the creak by pressing down alternately on the left and right pedals. The creak seems to be coming from the down tube.

Now, I know there are plenty of reasons why a crankset can creak. I have a SRAM Force 1, and they're apparently notorious for creaking. I also know that sound can 'travel'. My concern, however, is there might be damage to the down tube and that the pedals are exerting a twisting action on it which results in the creak and might eventually cause it to fail. There's no cracks that I can see. Is it possible for carbon fibre to creak in this way?

Andy

I think it's pretty much inconceivable a carbon frame would be damaged by hitting a pot hole.

[foxyrider]

I went over a nasty pothole recently - double puncture and a torn tyre. Somehow managed to stay upright.

Ever since I've had a continuous creak when pedalling. I can reproduce the creak by pressing down alternately on the left and right pedals. The creak seems to be coming from the down tube.

Now, I know there are plenty of reasons why a crankset can creak. I have a SRAM Force 1, and they're apparently notorious for creaking. I also know that sound can 'travel'. My concern, however, is there might be damage to the down tube and that the pedals are exerting a twisting action on it which results in the creak and might eventually cause it to fail. There's no cracks that I can see. Is it possible for carbon fibre to creak in this way?

Andy

I think it's pretty much inconceivable a carbon frame would be damaged by hitting a pot hole.

but not impossible

That said, i'd start with the Q/r before searching further afield, its the only thing that has potentially changed from pre pot hole to after

[AndyHenderson]

Thanks for the replies. Not sure whether to be reassured, or not.

Re: quick release - first thing I checked. I know where to look for creaks, I'm just worried the frame might be damaged.

Andy

[Marcus Aurelius]

My guess is a bent QR.

[mig]

being on the cautious side i'd check both the fork blades and, crucially, the steerer tube.

would you happen to know the steerer material? and hence if it is bonded to the fork crown.

[Brucey]

can you make it creak by pressing on the pedals when not seated, i.e. when reacting the load into the saddle, that narrows down the range of possibilities a bit. It is certainly not impossible for carbon to be damaged or to creak once it is. In the grand scheme of things it is much more likely to be 'something else' but that covers a wide range of things.

If you cannot identify and correct the source of the creak then you should at least be mindful of the places where it could have the worst consequences; mig's advice about inspecting the fork is along these lines; if the fork is damaged and gives way whilst riding it could kill you. Many other types of failure are less dangerous than this.

cheers