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Retorque cranks to about 30 ft-lbs?(10 posts)

Retorque cranks to about 30 ft-lbs?the bull
May 21, 2003 9:01 AM
Do the cranks on a square taper style Bottom bracket need to be retorqued as needed? The Insructions I have dont say anything about this.But I think it might be a good Idea to check once and awhile.
re: Retorque cranks to about 30 ft-lbs?ukiahb
May 21, 2003 10:59 AM
yep, they often loosen up after a few miles, and I've seen them get damaged if they were not re-torqued, though I've found retorqing them once or twice is usually sufficient, maybe after about 50 miles, and again at about 100...
Be careful here!Kerry
May 21, 2003 4:42 PM
The fastest way to destroy cranks is to keep tightening the fixing bolts on a regular basis. You should torque them well when installing and then after 50 miles or so just check to see that the bolts aren't loose. Torquing once probably won't cause trouble, but continually re-torquing will force the crank farther and farther up the taper and then quite possibly split the crank.
re: Retorque cranks to about 30 ft-lbs?russw19
May 21, 2003 4:43 PM
Hey Bull, just be careful about this.. that's one of the biggest knocks on square spindles.. everytime you tighen the bolt, they move a little further up the spindle. So whereas checking your bolts to make sure they are staying tight is one thing, grabbing an allen wrench and tighening them every week even if they don't need it is not a good idea.

On the other hand, if they loosen and you still ride them, if can wallow out the aluminum of the crank and they will never fit the spindle properly again.

Russ
Hey Kerry, "JINX!" -nmrussw19
May 21, 2003 4:44 PM
JINX 123!! (nm)Kerry
May 21, 2003 5:24 PM
Thanks guys!nmthe bull
May 21, 2003 5:34 PM
Apply the specific torque onlyCalvin
May 22, 2003 4:57 AM
If you do check bolt security, it is not necessary to move it clockwise each time you check it. In this situation, use a torque wrench. Simply apply the specified torque. If the bolt was loose, it will move unitl tight. If it was already tight, the wrench will show it, and extra torque will not be added.

For beam-type, just go up to the torque on the scale. For click-type, dial up the 300-inch pounds. If the wrench click immediately, you are done.
Do Not RetorquePsyDoc
May 22, 2003 6:25 AM
I read a post awhile back on one of the cycling message boards that once you set a fastener with a torque wrench, you should not go back and periodically check it as this puts additional torque on the bolt even though the setting on the torque wrench is the same. Something about the bolt "relaxing" a bit, but the torque level is correct. The person who posted the "warning" was an aircraft mechanic...I think.
Campy says!the bull
May 22, 2003 2:40 PM
Check periodically to make sure that the crankset is tightend to the correct torque wrench setting.
then it says 23.6 - 28 lbs ft.
But the "minus" is a "division sign!
Why do they do this crap!
But anyway I am only going to check tourque once at first torqued spec (28) then peridically check at 24 lbs.
probally every 5,000 miles.As long as the bolt does not move then I should not be concerned.