Shimano deore bb52 hollowtech ii bottom bracketthe deore sm bb52 bottom bracket cups for shimano cranksets with integrated axle offers better sealing performance than the precursor version sm bb51 the seal design provides smooth rotation and longer durability features compatible with fc t551 fc t611 fc m552 fc m590 fc m610 fc m612 fc m615 fc m622 fc m625 fc m640 fc m645a 2 year warranty is offered with all shimano products from chain reaction cycles 3 years on dura ace and xtr prod