Howitzer 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 our design is agility. Time to switch your bike, but love your cranks? No problem, just purchase another properly sized Howitzer BB for the new ride and remount your cranks. Howitzer is a purpose-built system featuring CNC machined AL-6061 cups, chromoly spindle and extreme strength through design.