Fit BB7s. Cheaper in the long run and a much better brake. Seriously I upgraded my Kettwiesel after running BB5s for 1000 miles, the right wheel's pads were worn out. The BB7s have done 4000 miles on the original pad, work better with lighter grip than needed for the BB5s and have been adjusted once. I could need to adjust the BB5s 3 times in 20 miles!