I still drag race with a solid hub, drop the hammer on yellow, then just pull the handle. Don't need no silly springs unless you're on the street..... McCleod's web site explains clutch hubs quite well, if you still have questions after that they have a group of very sharp techs to handle most any question you can come up with. Next thing I put a street clutch in I'll use their dual disc with a lite 'wheel; no chatter, no huge pedal pressure, with mild heat it will hook and launch just a bit this side of a Soft Lok!!!!!