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Old 08-28-06 | 03:02 AM
  #22  
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poprad
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Joined: Jun 2005
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Bikes: 07 Vanilla, 98 IRD road frame built up with 25th Ann DA, Surly cross check with 105 comp, 78 Raleigh Comp GS, 85 Centurionelli

Originally Posted by sivat
Another tip, you should use grease, assembly lube or loctite on every thread. I use loctite on the crank bolts and grease on everything else. It will help you put the right amount of torque on the bolt and keep the bolt from loosening while riding.

I would respectfully disagree with this as an overall recommendation. It depends on what the manufacturer spec'd for that particular fastener. Many torque specs are for dry threads only, and you can actually over torque a fastener by lubing prior to assembly because the lube will reduce the friction, thereby the indicated torque. That's why engine build manuals will frequently tell you if the bolt should be torqued wet or dry. A good manual will tell you which bolts require lube/anti seize/ or loctite. I can't remember but I think my Barnett's does.

If you're really interested in this arcane stuff, there's a few really good articles out there. When you get into the science of it, torque specs are really a bad (but only) way to tell someone how tight a bolt should be. Variations in thread pitch and tolerance from one fastener to another can make the torque readings vary significantly for a given setup, as can differences in the finish of the threads (chrome/machined/coated). Having said that, the aerospace industry uses torque specs on almost every significant bolt, and they fall out of the sky if they're torqued wrong.

One note, too much clamping force on critical components could cause micro cracks (invisible to the eye) that when stressed (bunnyhopping a log, etc...) could result in critical failure. In a seatpost for instance this could result in serious injury, so I would suggest really paying attention to manufacturer provided torque specs for critical areas. They don't pay those engineers to dream that stuff up for nothing, their lawyers make them do it so when the LBS can't testify they torqued it right, the LBS takes the "fall" not the manufacturer. This applies to you, the owner, because if you can say you used a torque wrench and then the fork (handlebar, seatbinder, other) failed in normal use causing you grevious injury, the maker can't say it was your fault for poor installation. Sounds like an overly complicated and redundant thing to do...until you're the guy missing part of his jaw...or the LBS being sued by the guy missing his jaw.

And I like torque wrenches..my Pedro's is a nice piece of kit.
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