Carbon fibre post slipping ...

gabriel959

Hi guys,

My AlphaQ seatpost is slipping in my Sabbath Ti frame. Any ideas why? I am using the FInish Line Carbon Fibre paste to "grease" it... Any ideas why this is not working?

Cheers,
Gabriel

Ben6899

Is it the right size?

Are you using enough torque? Probably about 5Nm given the paste...

gabriel959

yes, to the first one.

I don't know to the second one!

Ben6899

I would double check the manufacturer's torque setting specifications (usually ~5 - ~8Nm) and borrow a torque wrench. At least then you can rule that out if it's still occuring... worth noting that 5Nm is "tighter" than you might imagine.

gabriel959

It says ...

Secure the saddle in place by tightening the saddle clamp with a torque wrench
to 7-10 ft lbs.

How much is that? 5 nm?

Ben6899

10 ft-lbs is ~13Nm

http://www.convertunits.com/from/ft+lb/to/N+m

But when it says saddle clamp, I'd suggest that's the clamp under the saddle (at the rails) and not the one which secures the post in the frame.

gabriel959

There is no other indication about which Torque should it be tightened to though...

I nstallation instructions:
1) L oosen seat tube binder bolt/clamp of the bicycle frame
2) Clean the inside of the seat tube with mild detergent or solvent to remove any
grease and dirt that may be inside. This will prevent slippage.
3) Tighten the seat tube binder bolt/clamp in 1/4 turn increments until the post is
gripped firmly
4) L oosen the saddle clamp assembly with a 6mm allen key
5) Insert saddle rails in the rail groves of the saddle clamp.
6) Make fore/aft and tilt adjustments to the saddle to the desired position.
7) Secure the saddle in place by tightening the saddle clamp with a torque wrench
to 7-10 ft lbs.

Ben6899

Hmmm, nothing there regarding torquing the seat post... you tried the 1/4 turn increments method I take it?

I'd go for 5Nm and see what happens.

gabriel959

Yes - It feels tight to me and with it being a carbon fibre post I don't want to over tighten it.

Ben6899

Yeh, I'd try about 5Nm for starters. Do you have a torque wrench or could you borrow one?

topdude

I find 5Nm is about as tight as i can do it up by hand with a normal allen key.

Ben6899

topdude wrote:

I find 5Nm is about as tight as i can do it up by hand with a normal allen key.

I would agree with that. Unless you're Hulk Hogan.

keef66

Me too. Carbon post in an alloy frame. Carbon assembly paste stopped it slipping when tightened by hand with an allen key.

If yours is still slipping either it's too small for the seat tube, or the seat tube clamp isn't doing it's job