Thursday, March 19, 2009

Q&A: Seatpost binder bolt torque, creaky seat, bent derailleur hanger

Q: I just overtightened a seatpost clamp and stripped the threads. I got a new one now. How much torque can I put on this clamp? I have a Thomson aluminum seatpost.


A: Hi Steve,
Unfortunately it's not easy to give you a torque and be sure that it's right for your frame, clamp and bolt. I wouldn't tighten it with a torque wrench unless I had the information from the company that made those parts. Instead, what I'd do is make sure the bolt is lubed with grease, and then tighten it carefully. It only needs to be tight enough to hold the seatpost from slipping. You tighten the bolt and then you test your seatpost tightness by grabbing the seat and trying to turn it to see if the post is tight yet. Overtightening is very common so go a little at a time until the seatpost is held fast. That's the best way to go about it. If you have a torque wrench you could then check to find out what torque you tightened it to and then use your torque wrench in the future since you have a number for your exact setup.

If you would like to investigate torque settings further, there is a good page on Park Tool's site here: In it they recommend 36
to 60 inch pounds of torque for seatpost binder bolts, but caution to use care. Also the seatpost bolt torque is marked as coming from Campagnolo, so it may not be correct for your frame, bolt and clamp.

Tightening carefully is the best way to go usually,

Q: Hi Jim,
I emailed you some time ago in relation to a creaking seat, which I've now managed to solve. FYI, It turns out the Fizik Arione saddle with Ti rails sits on a FSA Carbon K-Force seatpost had gathered dust under the aluminium cradle and was causing the creak. I stripped the seatpost and applied Silicon spray to the area, dried it completely and now presto, no noise.

In any case, Jim I'm emailing you since last week I fell off my bike onto tram lines here in Melbourne, Australia (we have plenty of them). It was a cold and miserable day and I got caught in the rain and my front wheel slipped on the wet track and down I went.

I took the bike to my mechanic. It is a carbon fibre Basso Laguna. The rear derailleur appears to be ok, though the mechanic mentioned that this had been the third time he had to straighten the rear dropout/hanger. He suggested I would need to get a new one, but I can't seem to find one here in Australia. The local distributor is away at the Taiwan bike show and not contactable. Any suggestions? Do you think after 3 alignments, the hanger would need replacing?


A: Happy to hear about your seat (thanks for sharing the tip), but sorry to hear about your crash, Tony. Glad you're okay. The mechanic who fixed the derailleur hanger should have a feel for how weak it is now. They get weaker with each alignment but as long as they stay stiff enough to hold the derailleur steady they will keep working. I would think you could keep
riding with it and in the meantime order a backup so that you can change it out when that comes in. The company I know that makes the best assortment is Wheels Manufacturing. Your bike shop should be able to order from them (they don't sell direct to consumers). You could also order them online at

I like to keep a backup on hand for my Cervelo and I'd recommend you get one to be safe should your bike start shifting poorly, a sign that the hanger is too soft and getting bent with every little bump.

Hope this helps,

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