None, in all seriousness, while I've never actually measured it, but I expect that no more than a quarter turn of the adjusting knob is all that is needed to go from the rim touching for the whole circumference to not touching anywhere. When spun in the hand there should be no visible movement indicating any type of hop at all. I also don't think this is nit picky, at high speeds I don't want anything that can even remotely throw off the way the bike feels.