Creaky carbon frame???

[wookiee]

Hi

What I thought was a creaking bottom bracket in my carbon frame isn't! After fitting a new BB its still there! What could it be...it only occurs when I am out of the saddle putting a lot of force through the cranks. It sounds like a cracking rather than a grinding if that makes any sense! I have checked and checked again the frame for cracks but can't find any. Might be the pedals but it sounds like its coming from the frame around the BB area. Did wonder if it was the freehub on the rear wheel? Or could it be the chain?

Help before I go mad!

Doug

 

[P20]

Are the dropouts tight? Does it do it with the seatpost out of the frame

 

[wookiee]

Are the dropouts tight? Does it do it with the seatpost out of the frame

Will check the drop outs when I get in from work...haven't tried it without the post in either...thanks

 

[citrixccea]

Could it be the crankset ? Do you have a spare to try ?

 

[wookiee]

Could it be the crankset ? Do you have a spare to try ?

A possibility but its a new XTR one around 6 months ago and no I don't have a spare one to try out...could it be that I need to use "carbon paste" is assembling the bike parts (seat post, BB etc?)


Could be creaky pedal threads although it sounds a bigger cracking sound than they would produce!

 

[walleater]

I'd certainly apply carbon prep to the seat tube. Slight flexing of the seat tube can cause the seat post / tube interface to creak when dry. It'll also help the two parts from seizing which is pretty common with carbon as they are often a tight fit.

Loose rear wheel spokes is another thing to look at.

 

[02gf74]

is it a new or s/h frame? has it always done this?

if you are off the saddle, then I don't see how it can be the saddle or seat post.

does it creak in the same place on the pedal stroke - if so, where on the stroke - on one side or both sides?

what bottom brakcet type is it?

can it be headset/stem/bars?

 

[wookiee]

Well after another strip down here is what I have found...

- BB is fine XTR and brand new
- Chainring bolts all tight
- Still makes the creak/crack with the seat post removed
- Greased pedal threads
- Rear dropouts tight


BUT...when I changed the rear wheel for another (albeit a 26"!) the creaking stopped! My thoughts are now that it could be the freehub on the rear wheel...it spins quite stiff but with no play, but does sound a bit grawnchy when listened to close up. How ever I have a big fear now that the freehub looks like an integral part of the hub!! Therefore not sure that I will be able to just change the freehub and it might be a whole new hub and wheel re-build!! :shock: The hub is a Bontrager rxl and the number on the freehub is FH-68-P5 (see pics)

Any ideas if I can just change the freehub?

Doug

 

[02gf74]

I doubt very much the fh is integral.

I recently remved a bont. Fh using large allen key i will pst back on the size

Removal id different to shinano as the key fits in from the non cassette side.
The fh was on tight and i suspect i crackex the hub so had to buy a new hub fom usa as it was rare 28h hub .... annoying to say the least.

 

[Scarfacexxx08]

I had a similar problem, and found it was dirt under the hanger. Cleaned it out and hey presto. ..