Designed to handle the roughest terrain, the CZR i30 wheels feature a strategically reinforced carbon layer, reinforced spoke bed and are hand-spliced with double-butted spokes, brass nipples and high-quality Frequency hubs with top-of-the-line bearings with perfect sealing.our CZR i30 rims proved to be 10% more impact-resistant than their direct competitors in an independent laboratory test. If you break our CZR carbon rim while riding and you are the first owner, we will replace it for free. No exceptions!uSAGE: Trail - Enduro Wheel Diameter Position Spacing Spoke Holes Driver Body Rotor Mount Inner Rim Width Rim ERD* Weight** Max Rider Weight Part Number 29" Front 110x15mm 28-hole n/a 6-Bolt 30mm 589 878g 300lbs W045-0256 29" Rear 148x12mm 28-hole Shimano MS 6-Bolt 30mm 589 1033g 300lbs W045-0258 29" Rear 148x12mm 28-hole SRAM XDR 6-Bolt 30mm 589 1026g 300lbs W045-0257