Yeah, but most people on mods run 18:12 or 18:13 Not 20:12. But it's your choice. I'd stick with a screw on sprocket, it might of just been your cranks/sproket, but if you want a bolt on, then get middleburns . Mat
I think you can, but you don't need them anyway, a skrew on is fine, just dont cross thread it and it's reet. You want a 18t cog up front on a mod anyway, and they only go down to 22 or something. Mat