Big bikes need rock solid parts, and this includes the bottom bracket. If you're running a rig with a 100mm threaded BB and you're installing 24mm spindle cranks, such as those from Shimano, FSA, Gravity, Race Face, or Surly, we can make a hearty recommendation or two. First, pick up Chris King's ingenious new ThreadFit 24 Bottom Bracket. Its quality and durability are second to none. Then you're going to want the Chris King Bottom Bracket Conversion Kit 16. 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.