Bicycle Mechanics - Torque on Stem / Faceplate
Bikeforums.net is a forum about nothing but bikes. Our community can help you find information about hard-to-find and localized information like bicycle tours, specialties like where in your area to have your recumbent bike serviced, or what are the best bicycle tires and seats for the activities you use your bike for.
08-20-11, 10:08 PM
When reinstalling a threadless stem and faceplate, is it necessary, in terms of safety, to use a torque wrench? I generally use a sharp increase in resistance as an indication of tightness, though I suppose that this method might not be appropriate... particularly when using carbon components.
As important than the final torque, if not more so, is the sequence of tightning, and keeping both upper screws and both lower matched as pairs. When kept matched each screw does half the work, but if not matched it's easy to over tighten or stress the tighter bolt.
As far as the torque wrench goes, I'm more a believer in calibrated fingers and awareness of how the torque is ramping up as I come to working tightness. Also keep in mind that some stems that don't have thread inserts will have lower torques limits than you'd expect based on screw diameter.
I bought one of these - preset torque wrench that tightens to 5N-m. http://www.jensonusa.com/store/product/TL295J00-Ritchey+Torque+Key.aspx?sc=FRGL
Concur wiht FBinNY - important to make sure each shares the load. I usually tighten in a cross pattern, a little each time. I may do three passes (light, medium, medium hard) before the final torqueing.
EDIT- added web site.
08-20-11, 11:14 PM
Yea, I've seen this before but its unfortunate that it isn't adjustable... has anyone ever seen an adjustable torques wrench in this format?
Better off getting this for another $10 with a range of 0-100nm:
08-20-11, 11:25 PM
For carbon stuff, using a torque wrench might be more important. But I can't say for sure. The only thing I use a torque wrench for is tightening cranksets. I've already ruined one by leaving the bolts too loose and I don't plan on doing that again. But once I learn what ~40ft-lbs feels like I'll probably just do without.
08-20-11, 11:42 PM
Not only for carbon, I have a 3T alloy stem with TI bolts and torqued to max specified and "ping" broken bolt. I replaced with stainless. I use a torque wrench and don't go quite to max torque either.
08-21-11, 12:57 AM
carbon components definately have torque specs. I use an adjustable torque wrench on my seatpost clamp, and stem bolts. My fsa carbon over alum neck has the spec printed directly on it. ypou can just barely see it between the 2 lower bolts
Powered by vBulletin® Version 4.1.12 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.