Truvativ howitzer xr bottom bracketthe howitzer bottom bracket system provides a bombproof bottom bracket for the extremes of freeride and dh applications it bb features oversized cartridge bearings to produce a super durable external bb system we built this system from the ground up and it is built for abuse and yes it can take it over and over another benefit to the truvativ design is agility time to switch your bike but love your cranks no problem just purchase another properly sized