I like to put some drag on my wheels to help keep from running off our rather-short runway. It also seems that the wind turns around when I'm on short final! Starting from the inside, I have a wheel collar, metal washer, wheel, fiber washer, O-ring, then the final wheel collar. I use a slip-joint pliers to squeeze the collars together to give the right amount of drag. Because of wear, I have to adjust the tightness every 10 flights or so. Thus, many of the techniques here won't work. I just put a small blob of Goop on the end of the axle. Despite not having tightened the grub screw down adequately more than a few times, I've never lost a wheel.