The SRAM PowerSpline bottom bracket features a proprietary spline design used with many OE spec moderately priced TruVativ cranks.Crank bolts are includedHeat treated chromoly 12-spline spindle to make sure it can go the distance with even the most demanding riders TECH SPECS table{border-collapse:collapse;width:100%;} td{text-align:left;padding:8px;font-weight:350;} tr:nth-child(even){background-color:#f2f2f2} th{background-color:#eb212e;color:white;text-align:left;padding:8px;} .desc .specs-heading{font-size:24px;font-weight:600;padding-top:35px;border-top:3px solid #f0f0f0;display:inline-block;border-bottom:4px solid #eb212e;width:142px;margin:0;} Bottom Bracket Shell I.D. 1.37 BB/Frame Interface English BB Shell Width (mm) 68 Spindle Interface Type Truvativ Power Spline Spindle Length 113 Defined Color Black Shell Width 68Mm