just a random question I'm pondering. The extra notches in the direct drum are different in every drum I've seen. Are they cut in after the drum is built in an effort to balance it? Some sure seem to have a lot of weight cut out of one side and with the rpm these spin in first I'd assume they want it pretty well balanced. Has anyone tried to check/rebalance them? Is this why some have ring grooves at low miles and others look cherry after a hard life?