Crank installation recommendations

Unicycles and Equipment
1

Hi,

I just bought a coker at the cranks are often comming loose during my ride.
I am using a dead blow hammer to seat cranks before tightning. Any recommendations for installation or things to watch out for? How much torque should I apply when tightening the bolts?

Thanks

2

My Coker cranks uned to get loose after my rides. I just tighted them up and it haven’t came loose it since last summer. Maybe you just need to ride it a bit and it will stop… I dont why it would do that though:p

3

I’ve never needed to use a hammer to tighten cranks. I just tighten the bolts until they are tight. A lot of force can be applied- until the bolt breaks. I’ve only had that happen a couple of times and I was tightening it as hard as I could- and perhaps they were not the best bolts. Carry around the tool and tighten as soon as they get loose on your first few rides. If you don’t do it immediately sometimes permanent damage can be done.

4

Campy says about 25 ft/lb’s for crank bolts with clean spindle flats. This is with greased bolts, but no grease on the flats. Some old school mechanics recommend putting some light oil/grease on the flats, and wiping it off. This will leave a very thin film of oil that will help the crank seat. If you do this I suspect that you will need less torque.

I haven’t ever had a problem with them coming loose by just doing them “tight.” If you are having a recurring problem I would check the flat’s on your cranks and make sure that they are still flat and not flared. Once they flare from riding loose the only real repair is to replace the crank arm.

5

I’ve had a similar experience and I’ve been thinking about the loosening issue.

According to Jobst Brandt, a mechanical engineer and long respected bicycle enthusiast, retightening then cranks can be part of the problem…

I don’t know what to make of this.

6

I agree that you shouldn’t have to re-tighten your cranks once they are set. I always lube my spindle flats and wipe off the excess. I haven’t had a crank creak, or come off since my early BMX days.

As much as I have differing opinions with Jobst Brandt on some topics, I think in this case he hit the nail on the head.

7

great feedback

Thanks for the great feedback