Originally Posted by
Jeff Wills
.. A square-taper crank bolt requires 25-35 foot-pounds of torque. Grease the threads on the bolt. Whether you grease the tapers on the spindle is up to you- there's opinions on both sides. Rechecking the torque after riding a week is a good thing, IMO, but after that they should not come loose.
+1 Proper torque is very important. 30 lb-ft cannot be attained with a multi-wrench or an L allen wrench. Rather, it's best to do with 3/8 drive allen bit socket and a 15" torque wrench. Assuming you install with the recommended torque and the arms are in good shape (square holes still square), they should not inadvertently loosen. And good to grease the threads. I grease the tapers, but as mentioned, it's one of those third rail topics on BF (along with "WD-40 as chain lube").