This bottom bracket fits a Sram GXP crank on a classic BSA threaded road frame. Choose road seals for road use. Choose cross seals for gravel, CX, and commuter bikes or if you frequently ride on wet roads. For installation, use a 16 notch tool with an internal diameter of 42.7mm (measured at the inside of the notches). This is your most traditional tool for BSA bottom brackets, previously used by Sram GXP, Chris King, Campagnolo and older style Shimano. Example: Park tool BBT9 or BBT 69.4