Crupi Pro 36H Wheels are still the fastest Spring & Pawl Engagement System in BMX! The Quad Hub features 150 ratchet teeth which engage every 2.4 degrees so what you get it is a super fast engaging hub. Features: Fixed independent leaf spring/pawl system acting simultaneously when engaged Less resistance and less wear = a smoother rotating hub 16T chromoly cog included but designed to work with any Shimano compatible cog NO Rider Weight Limit Specifications: Wheel Size: 20 x 1.75" Rims: Rhythm Hubs: Crupi Spokes: 14 gauge Color: Red Hubs and Nipples Weight: 3 lb 13 oz