Originally Posted by
Ghrumpy
What holds a taper fit on? Friction.
No, not friction. The preload high enough to prevent movement even with some elastic deformation from pedaling torque is required to minimize fretting and the interface damage, cranks coming loose etc.
Originally Posted by
Ghrumpy
If a crank is properly pressed onto the taper, you should not get any of the latter.
It does happen, due to elastic deformation and motion of metals. Grease reduces the effect, mounting paste even more so IMO.
Originally Posted by
Ghrumpy
By the way, the bolt does not hold the crank on. It presses it on, but after that it serves to keep it from coming off. How? By preventing repeated relative motion.
This is easily verified experimentally.
Yes, the bolt prevents the crank from sliding off.
Originally Posted by
Ghrumpy
I claim that lubing tapers more easily enables overtightening of the crank (among other things.)
This is not correct IMO, but I see no point in going round in circles.
Originally Posted by
Ghrumpy
Campagnolo didn't just make cranks and ship them off and never think about them again. They have for 60 years provided racers and racing teams with them, and also race support. They have experience with their products from production to the end of their service life. They've seen the mistakes and the failures along with the successes. They have big numbers.
And have failed to make corrections. One example is the pedal to crank interface being kept flat, instead of tapered, which also allows fretting damage and requires left hand thread on the left pedal to prevent it from loosening through use.
Originally Posted by
Ghrumpy
If their instructions don't make sense to you, the problem might not be with the instructions.
Could be, but I don't think so.