Originally Posted by
miriam
Who ever set up the motor with the machine wore a good groove in the wheel didn't they?
Yeah, I noticed that. I think the idea is to provide only as much friction as necessary to drive the wheel. So if the pulley is centered, there's more contact and more friction. I guess it's the same as the principle for belt tightness. The tighter the belt, the more force on the pulley. And friction is a force.