The Answer Holeshot Pro cassette hubs feature lightweight CNC machined aluminum hub shells with laser-etched logos, precision sealed Japanese bearings throughout, 14mm hollow aluminum center axles with 3/8″x24tpi chromoly axle bolts and a 6 pawl aluminum driver with 16T Shimano style cog. Each driver pawl has 3 individual teeth that engage every 3 degrees for near instant engagement and off the line acceleration. Weight: 19.2 oz Front OE Replacement PartsCenter Axle: 14mm Hollow AluminumAxle Bolts: 3/8″x24tpiHardware: AluminumHub Shell Bearings: 15268 (x2), verify bearing number on side of rubber sealWeight: 6.4 oz Rear OE Replacement PartsCenter Axle: 14mm Hollow AluminumAxle Bolts: 3/8″x24tpiDriver: Aluminum w/ Shimano Style 16T CogDriver Bearings: 6902 (x2) Verify bearing number on side of rubber sealDriver Pawls: 6 Pawls w/ 3 Teeth Per PawlDriver Spring: Individual (x6)Hardware: AluminumHub Shell Bearings: 6902 (x2) Verify bearing number on side of rubber sealWeight: 12.8 oz w/ 16T cog Hub Specs:Front Diameter: 40mmFront Center to Flange: 32.5mm Rear Diameter: ND: 45mm D: 58mmRear Center to Flange: ND: 28mm D: 26mm