This winter, treat yourself to some new bottom bracket bearings courtesy of the FSA Mega Exo Cartridge Sealed Bottom Bracket, then set about trying to destroy them as soon as the trails are rideable in spring. This will be a tall order, as the bottom bracket's aluminum external cups are precisely CNC machined, so they soak up abuse without flinching. They also house oversized stainless cartridge bearings for corresponding internal durability. The composite center sleeve has double O-ring seals to keep the outside out. It's also compatible with Di2 wiring. The FSA Mega Exo Cartridge Sealed Bottom Bracket is threaded for English (68mm) and comes in three variations: 24mm NBD, 68/73mm, and 68/73 and 83mm.