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Old 11-13-11 | 01:34 PM
  #25  
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Brian Ratliff
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Joined: May 2002
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From: Near Portland, OR

Bikes: Three road bikes. Two track bikes.

The torque spec on a 3mm bolt means next to nothing. Torque specs are pretty much worthless for bolts less than 1/4" due to high variance in thread friction. To illustrate, insert the bolts dry and 5Nm will might have the bars slipping. Put grease on the threads and at 5Nm you might have enough bolt tension to crush the bars. The important is bolt tension; in big bolts, tightening torque correlates well with bolt tension. In a little bolt, thread friction is a huge factor and the correlation between bolt tension and tightening torque is not good.

Also, the 5Nm spec given for stems is 1) a maximum to keep for stripping the bolts, and 2) for the stem, not the handlebars.
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Last edited by Brian Ratliff; 11-13-11 at 01:41 PM.
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