himano BB-MT501 Bottom Bracket ? BSA 68/73mm Hollowtech II (OEM, No Retail Box) Description: The Shimano BB-MT501 is the next-generation Hollowtech II bottom bracket, built for smoother rotation and better sealing than the SM-BB52. It delivers efficient power transfer and improved durability for mountain, trekking, and e-bike applications. Ideal for riders seeking low friction and long service life in all conditions. These are OEM Shimano Parts ? Brand New, Never Installed, Never Used, just NOT in Retail Packaging. Key Features: Model: BB-MT501 Type: External Bottom Bracket (Hollowtech II) Thread: BSA (English 1.37? 24 TPI) Shell Width: 68 mm / 73 mm Spindle Diameter: 24 mm (for Shimano Hollowtech II cranksets ? Deore / SLX / XT etc.) Sealing: Enhanced labyrinth contact seals for superior dust and water resistance Material: Lightweight aluminium cups with sealed cartridge bearings Color: Black Weight: Approx. 82 g Package Includes: Left right bearing cups (with pre-installed bearings) Center sleeve 3 2.5 mm spacers (for 68/73 mm shell adjustment) Inner O-rings Compatibility: Fits Shimano Hollowtech II MTB and Trekking cranksets (e.g. FC-M5100, M6100, M7100, M8100, M8120 series) For frames with BSA threaded shells only (not Press-Fit types) Installation Tips: For 68 mm shells: 2 spacers drive side + 1 non-drive. For 73 mm shells: 1 spacer drive side only. Apply grease and tighten to Shimano specified torque.