Friction ring for lens or wheel

I have a telescope and the rubber rings on the focus wheel have degraded and fallen off. This is a parametric design to replace such rings. It could be used for any kind of wheel that needs a friction grip.
You'll obviously want to print this out of TPU or some other flexible filament. TPU doesn't stretch that much so it needs to be not much smaller than the diameter of the wheel it's going on.
Modify the SCAD to change diameter or width or size and distribution of the knurling.