jeff3069

Hi everybody,

Rode a 1st ride with a new Cervelo S5 (in a wet weather) and the seatpost slipped (approx 7 mm)

Used an allen-4 key (like the one in the enclosed photo) until it slightly twisted. don't want to over torque..

Will appreciate your advice on how to resolve this

Thanks!

habilis

If it still slips, it can't be over-torqued. In the absence of a manufacturer's torque value, tighten gradually and re-test by riding until it doesn't slip any more.

jeff3069

Thank you habilis.

habilis

Another thought: If the Allen tool is deforming, the threads on the clamp bolt may need to be lubed. That can dramatically increase the tightening for a given torque value, so be cautious, tighten gradually, and test-ride between increments.

jeff3069

Ok, will try that. indeed tightening was noisy.. Thanks!

habilis

Sorry to keep coming back - the coffee is just starting to work. Are you sure the seat post is the right diameter for the seat tube? The sides of the slot in the clamp should remain parallel when the clamp is fully tightened. If the clamp "ears" aren't parallel, it indicates that the post is too small and there's a danger of damaging the tube.

jeff3069

It's a new S5 frame with its original seatpost. will apply some carbon paste and hope this will resolve

dsbrantjr

With a carbon frame and components you would do well to invest in a torque wrench and a set of hex bits. Adequate ones are available from Harbor Freight for about $20 ($10 on frequent sale/coupon) and prices go up from there but still cheap compared to the cost of your bike and components. If torque values are not printed on the part, go online and look them up.
As suggested, grease all fasteners; they should not squeak or chatter when being torqued.

jeff3069

Thank you dsbrantjr.