Cup and cone bearing adjust

[Brian Smith]

Originally Posted by redir

I wonder if it's the threads that compress in a bit b/c I just cannot imagine a short steel pipe could compress over that short a distance? I am not metallurgist though. But on a micro level I can at least envision the 'kerfed' threads bending. or just the minute wiggle room between thread and nut?

No, that's not it, it's the fact that it is a (relatively) thinwall cylinder, in comparison to a bar, even a threaded bar. Compare the required adjustment required for exactly the same hub but using a solid axle, and you'll prove this to yourself. Same nuts, cones, bearings, hub, but different axle and clamping mechanism - different adjustment requirement.

[oldpotatoe]

Originally Posted by redir

I wonder if it's the threads that compress in a bit b/c I just cannot imagine a short steel pipe could compress over that short a distance? I am not metallurgist though. But on a micro level I can at least envision the 'kerfed' threads bending. or just the minute wiggle room between thread and nut?

Another thing that 'doesn't seem right'...New hub, not built, bearings/axle 'seems' tight, notchey. Build the wheel with 'proper' tension, the hub now feels smooth, not notchey.....Yup, the spoke tension does seem to pull the aluminum hub shell 'out' some..try it...

[professerr]

I’m gonna guess it is not the steel material itself that is compressing (which is what it is so hard to get one’s head around). Rather I bet it is the hollow axel structure that is compressing via barrel distortion (e.g. the sides flex and bulge out very slightly) or some other distortion (e.g. slight asymmetrical flexing to the side).

Either way, whatever the cause, there’s no question tightening skewers can cause cup and cone hubs to bind or run rough. The tighter the skewers, the more wiggle room you need to leave for the hubs to spin nice when mounted (e.g. chromed semi-horizontal dropouts vs modern vertical dropouts).