Carbon Fibre Forks Fecked?

Cyclepath

Gents, looking for some advice from any riders on Carbon Fibre. My Felt Speed 30 has plastic forks and I'm getting increasingly nervous about them.

I've always had Reynolds steel or CroMoly bikes and these forks just don't feel right. To my mind there's a worrying flexibility to them. It's most noticeable if I sit up for a rest and go hands free when the front wheel starts to wobble increasingly.

I can't see an issue with the wheel itself which is perfectly true but I also notice this slight wobble if I hold the handlebars either side of the stem and tuck the elbows in (e.g. when cycling into a head-wind).

Anyone have any thoughts? Is this normal?

Raam

My Allez wobbles on the front a bit like that if I cycle no hands. It has a carbon fork. None of my other full CF bikes wobble like that. My LBS says it's my headset. He tinkered with it and it was fine. That was a while ago. It's mostly fine these days, but every now and then she wobbles a bit. Nothing that worries me though.

check_six

My carbon fork became loose at the headset and was a bit wobbly. Tightened it up and it was grand, but then over time it worked itself loose again. The steerer tube and the headset can slide around all over the place if not tightened to the correct torque, and carbon can be particulaly slippery. I was a bit too ginger on the allen wrench and it kept slipping. Friendly mechanic in LBS gave the spanner an almighty twist (I was expecting splinters of carbon everywhere), and it's been grand ever since.

ps. My headset starnut equivalent thingy (can't remember the proper name) had some hidden wrong ways turning nut in it. Beware!

Cyclepath

check_six wrote: »

My carbon fork became loose at the headset and was a bit wobbly. Tightened it up and it was grand, but then over time it worked itself loose again. The steerer tube and the headset can slide around all over the place if not tightened to the correct torque, and carbon can be particulaly slippery. I was a bit too ginger on the allen wrench and it kept slipping. Friendly mechanic in LBS gave the spanner an almighty twist (I was expecting splinters of carbon everywhere), and it's been grand ever since.

ps. My headset starnut equivalent thingy (can't remember the proper name) had some hidden wrong ways turning nut in it. Beware!

Aha... yes I did try to tighten the headset and was afraid of over doing it. Might give it another go - seems to be the usual Allen key job, but I do have spacers in there to give me aul' aching back some relief...

ashleey

A quick pointer that has had me going mental until today:

I serviced my headset bearings and when I removed original fsa compression plug, half of it dropped into the steerer and I only got it out with some serious patience as it dropped slightly at an angle.
They have 2 mechanisms: One to compress the bung and one to tighten down the top cap.
Some brands effectively lose compression as they have a 1 bolt mechanism and are basically crap. You can't get compression because it wouldn't slide into the steerer and overall the headset loses tightness through road vibration.
I fished out my original fsa one and it is fine. The ITM replacement was junk.

ashleey

Forgot to add that with the fsa version, first you tighten up the bung inside the steerer. Then you put the top cap and bolt on and tighten that down to compress all the headset parts. Then you tighten your stem bolts.
Another trick to know is that if you can spin your spacers easily then your headset is loose

check_six

ashleey wrote: »

..compression plug..

Aha! That's the device name I was trying to remember. Thank you, it was driving me crazy.

ashleey wrote: »

Forgot to add that with the fsa version, first you tighten up the bung inside the steerer. Then you put the top cap and bolt on and tighten that down to compress all the headset parts. Then you tighten your stem bolts.
Another trick to know is that if you can spin your spacers easily then your headset is loose

The bung/plug must be tight in the steerer tube before doing any of your normal headset adjustment, this is what the mechanic tightened for me. On my bike (Felt) you had to push a 5mm allen key through the slot the cap bolt goes into (6mm) and turn anticlockwise to tighten. If the bung/plug/thing is not tight before you put on the cap any tightening you do of the cap is merely pulling the bung out of the steerer tube. I think there may be variations on bung designs so you may need to check before attacking your bike.

Cyclepath

check_six wrote: »

Aha! That's the device name I was trying to remember. Thank you, it was driving me crazy.




The bung/plug must be tight in the steerer tube before doing any of your normal headset adjustment, this is what the mechanic tightened for me. On my bike (Felt) you had to push a 5mm allen key through the slot the cap bolt goes into (6mm) and turn anticlockwise to tighten. If the bung/plug/thing is not tight before you put on the cap any tightening you do of the cap is merely pulling the bung out of the steerer tube. I think there may be variations on bung designs so you may need to check before attacking your bike.

Right, cheers, that sounds like it may be the problem. Mine's a Felt too and it would explain why tightening has had no effect...

ashleey

So undo the top cap and take care that the inside compression bolt isn't undoing at the same time ( that's what happened to me!). Then tighten the inside compression bolt. Loosen your stem bolts. Replace top cap and tighten down. Then finally tighten stem bolts. If when riding you get that tell tale 'clack' sound of carbon rattle you may need to do it all again but this time make sure all bearing races are snug and any race washers are secure.

Cyclepath

ashleey wrote: »

So undo the top cap and take care that the inside compression bolt isn't undoing at the same time ( that's what happened to me!). Then tighten the inside compression bolt. Loosen your stem bolts. Replace top cap and tighten down. Then finally tighten stem bolts. If when riding you get that tell tale 'clack' sound of carbon rattle you may need to do it all again but this time make sure all bearing races are snug and any race washers are secure.

Excellent thanks for the advice. I'll tackle this over the weekend, didn't want to start something I couldn't finish last night!

ashleey

No worries. Good luck. I'm just about to tackle my bb30 bearings. This could go well or..,

Cyclepath

ashleey wrote: »

No worries. Good luck. I'm just about to tackle my bb30 bearings. This could go well or..,

Eh, yeah I've one BB bearings disaster and ever since then I head straight to the LBS

endacl

Something like this...? :eek: