Originally Posted by
Slaninar
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.
A taper fit is a type of press fit, which depend primarily on friction to hold. There is some material deformation too but the friction of a press fit is doing the work.
I'm not saying fretting doesn't happen, nor am I saying fretting is OK. I'm saying the risk of damage from fretting is relatively less significant than the risk of other types of damage that a dry taper helps mitigate.
Originally Posted by
Slaninar
It does happen, due to elastic deformation and motion of metals. Grease reduces the effect, mounting paste even more so IMO.
Sure, grease does reduce friction. No argument there. Whether that's a good thing or not is the question, isn't it?
Yes, there is some elastic deformation of course, but it's manageable; that's what torque values are for, for both the fastener and the taper fit. It's the plastic kind I'm concerned about, which reducing friction increases the risk of by requiring different (lower) torque values that are usually not followed if they are even known.
Originally Posted by
Slaninar
Yes, the bolt prevents the crank from sliding off.
Glad that is settled, at least!
Originally Posted by
Slaninar
This is not correct IMO, but I see no point in going round in circles.
That's what we bicyclists do, isn't it? We almost always end up back where we started.
Originally Posted by
Slaninar
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.
That would be a handy solution, but this is hardly Campagnolo's fault. Pedals have been made that way since forever, so everyone who's ever made a pedal has failed to do this. Probably because it's not such a big deal if you don't overtighten them. (Not to start on another topic, but pedal overtightening is another pet peeve of mine.)