Square Taper Bottom Bracket Cartridge68/118mmSteel Axle/SleeveSealed Cartridge BearingsThe bottom bracket spindle — is a spindle and not an axle since it “spins” on the bearings — left and right side has a simple box-shaped or square end.The end is slightly tapered into a wedge shape, narrow at the end increasing in width to the back. The crank is pushed onto the wedge once the bolts that fit into either end of the spindle they apply enough pressure as you tighten them to the appropriate torque.Cartridge bottom brackets are cheap and convenient. They can last many years, because they are sealed from the elements, i.e. they contain a “sealed” bearing.There is no need to service this type of bottom bracket cartridge. If you are racking up thousands of kilometers in the saddle every year, they will keep you going.
