The e13 bb92 bottom bracket adapts ethirteen cranks with 30mm spindle to fit a bb92 bb107 and bb121 bb shell the bb92 bb is a specially made bearing that presses directly into frames providing a solid base for ethirteen cranks even frames with limited crank options custom seals grease fill and angular contact bearings are designed from the ground up for top notch durability and smooth spinning all of our bbs include our 1 year no questions asked bearing guarantee fits all xcx trs a