Bicycle Mechanics - Tightening crank arms

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various styles
07-11-12, 08:05 PM
So i"m about to tighten my crank arms with a torque wrench. Once i tighten my bolt to were putting some real torque is required, and my crank arm is at 6 o'clock and my ratchet is at 12 o'clock . How far do i turn the ratchet to the crank arm 1/4 1/2 3/4 of full circle. I got these cranks http://www.vueltausa.com/components/cranksets/pista-track-crankset-silver.html there was no torque specs on crank arms
HillRider
07-11-12, 08:08 PM
I put the torque wrench and the crank arm about 90° apart when applying significant torque to the wrench while holding the crank arm with my other hand.
various styles
07-11-12, 08:10 PM
And then meet in the middle?
reptilezs
07-11-12, 08:28 PM
for the non drive arm i lockout my elbow on my left arm on the drive side crank then reach over the bike and tighten with my right hand. for the drive crank i put the chain and wheel on and hold the rear wheel with my left hand and tighten with right hand
various styles
07-11-12, 08:54 PM
Alright thanks!
So i"m about to tighten my crank arms with a torque wrench. Once i tighten my bolt to were putting some real torque is required, and my crank arm is at 6 o'clock and my ratchet is at 12 o'clock . How far do i turn the ratchet to the crank arm 1/4 1/2 3/4 of full circle.
Huh?
If you have a torque wrench, you shouldn't be asking about how far to turn, the tool will tell you.
Either you'll have a beam style torque wrench, (http://www.parktool.com/product/torque-wrench-tw-1) in which case you just turn until the dial indicates the right value. Or you have the ratcheting, click-type wrench (http://www.parktool.com/product/ratcheting-click-type-torque-wrench-tw-6) in which case you simply turn until you hear/feel it click.
Sometimes angle of displacement, or bolt elongation is used in determining that something is correctly tightened. But that's at far bigger things than bike parts.
I got these cranks http://www.vueltausa.com/components/cranksets/pista-track-crankset-silver.html there was no torque specs on crank arms
Seems to be a dead standard square taper. Park has a torque recommendation chart (http://www.parktool.com/uploads/files/blog/torque.pdf), scroll down about 1/4. 305-391 inch-pound.
davidad
07-12-12, 06:00 AM
I shoot for 25 foot-pounds.
Huh?
If you have a torque wrench, you shouldn't be asking about how far to turn, the tool will tell you.
Either you'll have a beam style torque wrench, (http://www.parktool.com/product/torque-wrench-tw-1) in which case you just turn until the dial indicates the right value. Or you have the ratcheting, click-type wrench (http://www.parktool.com/product/ratcheting-click-type-torque-wrench-tw-6) in which case you simply turn until you hear/feel it click.
Sometimes angle of displacement, or bolt elongation is used in determining that something is correctly tightened. But that's at far bigger things than bike parts.
Seems to be a dead standard square taper. Park has a torque recommendation chart (http://www.parktool.com/uploads/files/blog/torque.pdf), scroll down about 1/4. 305-391 inch-pound.
all this.
A torque wrench can be dangerous. It is tempting to check the torque on the crank bolts after riding it just to see if the torque has changed. If you check you will see that the torque has decreased and the bolt needs tightening. If you continue to retorque the bolt you will end up damaging the crank arm and maybe even splitting the hole in the crank arm.
So torque the crank arm bolt to the correct torque and forget it until you need to pull the crank again.
HillRider
07-14-12, 07:11 AM
And then meet in the middle?
Yes, and if it does I just reposition the wrench as needed. What is so dfifficult about this?
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