Wheels are a good one.

All my pattern planes have coil spings and washers that hold the wheel against the bushing of the axle. They serve two functions. First of all the wheels don't rattle. Secondly they create resistance in the stationary position before take-off. Once they over come the static friction they spin quite freely, until the plane leaves the ground and then the spring pressure stops them turning.

You set the spring pressure with the wheel collar. I usually run the motor with the plane inverted on a stand. Then just tighten the spring until the wheel stops spinning on its own. - Done!