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stripping shimano chainring bolts like crazy(7 posts)

stripping shimano chainring bolts like crazysodade
Apr 14, 2003 5:36 PM
I bought a torque wrench today. I set it at 80lbs per Zinn's 70-100 for a chainring bolt. I turn and the inner hex of the bolt shreds. The socket allen wrench is now imbedded in the bolt and requires a vise and some creative hammering to get it free. I figure - it must habe been bum luck so I go for the next bolt as cautious as a mouse and it happens again. What am I doing wrong?

Thanks in advance...
inch ponds or foot pounds lol!!!the bull
Apr 14, 2003 6:24 PM
Christ you torque a car wheel to 80 ft lbs!inch pounds!!!not foot!!
**snicker!!**Alexx
Apr 15, 2003 4:07 AM
Unbelievable! The book calls for 80 in*lb, and he gives it 960!!! Can you say "torsional failure"?? Sure, you can!
so do I devide by 12 then? -nm-sodade
Apr 15, 2003 8:10 AM
YesCrankist
Apr 15, 2003 9:05 AM
Apparently, no one else here has ever made such a mistake.
No big deal; drill out the old ones if nec. and replace 'em.
Mike
get another torque wrenchDougSloan
Apr 15, 2003 9:43 AM
I have a 1/4" drive torque wrench calibrated in inch/pounds. Something like that would probably be preferable to a larger one and dividing by 12.

Nonetheless, you shouldn't need a torque wrench at all for this. I've probably tightened and loosened chainring bolts a thousand times without one and never had a problem. Lube the threads to make tightening smooth and removal easier.

Doug
fyi: torque wrench advice at VelonewsDougSloan
Apr 15, 2003 10:39 AM
http://www.velonews.com/tech/report/articles/3538.0.html