Originally Posted by
BCRider
Around here it's wet enough that steel rusts if left dry or with nothing but a light film of factory oil. Add to that this is an aluminium to steel joint and we have the makings of a galvanic party just like you get with an alloy seatpost in a steel frame. And we all know that EVERYONE greases those.
Completely different interface when dealing with a seatpost in a frame. The seatpost is not a press fit in the frame. There is clearance which will allow corrosion to form. The press fit of the spindle in the crank effectively seals out any corrosion from happening. I've never seen a corroded square taper end on a spindle after removing it from a crank. Have you? [edit] I don't mean for the tone of my question to be insulting. It's an honest question. Yes, I'm coming back over an hour after posting this to make this edit because it was bugging me the whole time. [edit]
Originally Posted by
BCRider
So yeah, I grease the tapers. Definetly for sure. And I've never had an issue with an arm coming loose on any of my bikes. Best of all there's no chance of the aluminium galling as it squeezes onto the taper. And years later they still come off fine thanks to no corrosion issues despite lots of commuting in wet conditions.
I don't go out of my way to grease the spindle before installing the crank arm but I also don't degrease new spinles. Hasn't seemed to make a difference either way. I use a torque wrench the first time and then don't touch it again.
If aluminum had a tendency to gall rubbing against steel, the standard aluminum piston/cast iron engine block configuration used in the vast majority of IC engines would have died long ago. Aluminum galls against aluminum hence the need for iron coatings on pistons or special cylinder wall treatments for aluminum engine blocks.