The Answer Pinnacle Pro race wheels are hand built using 36H Answer Pinnacle double-wall rims, laced 3X with black 15G spokes and lightweight alloy nipples, to Answer Holeshot Pro cassette hubs. The Holeshot hubs feature CNC machined aluminum hub shells, 14mm hollow aluminum center axles with 3/8? axle bolts, a 6 pawl aluminum driver with 16T Shimano style cog, and precision sealed bearings throughout. Each driver pawl has 3 individual teeth that engage every 3 degrees for near instant engagement. Features: Pinnacle double wall rims Answer Holeshot Pro Disc Cassette Hubs Precision Sealed Bearings Rear Disc Specifications: Wheel Size: 20", 24" Rear Axle: 3/8" Threaded x 110mm Front Axle: 20mm Driver: 6 pawl aluminum driver