Shimano Tiagra BB-RS501 Hollowtech II Threaded Bottom Bracket

• Hollowtech II Technology: Lightweight and stiff design enhances power transfer and pedaling responsiveness.
• Wide Shell Compatibility: Fits both 68mm and 70mm threaded bottom bracket shells for versatile use.
• Improved Sealing: New high-precision seal keeps out contaminants for longer-lasting performance.
• Threaded BSA Design: Ensures easy installation, secure fitment and creak-free operation.
• Optimized Bearing Placement: Outboard bearing system improves stability and load distribution.

Technology

• Hollowtech II: Integrates the axle with the crankarm for greater stiffness, weight savings, and more efficient power transfer. The outboard bearing design improves stability and load distribution by positioning the bearings outside the shell. The 24mm axle diameter provides optimal balance between weight, rigidity, and smooth rotation.