Truvativ howitzer xr bb 56mm chainline x 6868e7373etechnology external bearings heat treated cromoly spindle alloy cupsspindle howitzerbearings 2 sealed oversized cartridge bearingsweight 365g with oversized external mounted bearingsbottom bracket howitzer not suppliedshifting smooth ramped pinned shifting multiple ring optionschainrings al 7075 t6 chainrings cold formed cnc39doptions dh 3842 double 32 2236 24 incl p c rockguard triple 44 32 22 trials 22 incl al 7