Hi, just joined up and just about finished building up my Zaskar...but I've been offered a decent rear wheel at a decent price, but it's 9speed. I've got an 8speed just now , is there any difference in the dish of the wheel? I remember you had to have a whole new rear wheel built when upgrading from 7 to 8, but having measured my 8speed cassette and my fiancees 9speed, they seem to be the same width. Any ideas?