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@tynan
Dear cyclist folk.
I've just put a crank arm on a bike . . . . . . (the recommended torque is 38-42Nm)
Stupidly I was looking at the wrong gauge on my torque wrench, so instead of putting it on at 40Nm I put it on at 40ft-lb.
This means I actually put it on at around 55Nm, which is damn tight !
In fact it's so tight that the hex bit broke as it hit 55Nm!!!
So, my question, firstly I am going to leave the crank arm on the spindle as if I try and reinstall it I suspect having been shoved on a 55Nm if I try and mount it at 40Nm is will be a tiny bit loose . . . . . but leaving the crank arm out of the equation should I back off the tension on the crank arm bolt, as this is only preload it won't effect the crank, should I unscrew it and remount at 40Nm so it's not too stretched and the threads aren't under so much stress ?
Any input appreciated, especially if you are a mechanic.
Concerned of London.