New crank and an older frame No problem. First, pick up Chris King's ingenious new Threadfit 24 Bottom Bracket. Now, if you are running road bike cranks with a tapered 22 24mm spindle, such as certain SRAM, Bontrager, Truvativ, or Zinn cranks, and your bike has a 68mm wide BB shell, you're going to want the Chris King Bottom Bracket Conversion Kit 9. The Kit slips onto the crank's spindle and then into the Chris King ThreadFit 24 Bottom Bracket on your bike. If you have any more questions about which CK conversion kit to use, please let us know and we'll help you out.