I'm making batches of wheel sliders for my fellow road racers. Go for Delrin, I'm using it and it works good. They're crash tested too.
But I don't like the threaded axle-version, too much dead weight. I use two different ways, either it works like an expander or it's stucked in the axle with a couple of O-rings (Ducati Hyper-models use the rear axle for the pit stop stand, so the slider needs to be removable on one side).