Sorry it's been a while since I replied...this didn't work. The motion of the chainring moving kept pulling the chainring out of alignment. So I removed the chain and started again to try and get the chainring perfectly centered. This worked ok, it's better, but not perfect. What kind of shim could I use to get this thing on perfect-like? I'm riding my other bikes for the moment, and it's driving me crazy I can't ride this one as it's my favorite.