Groundbreaking RZR Big Bearing Hub and Spindle Kit is nearly 8 lbs. lighter per corner than stock. Incorporates a 30% larger wheel bearing at a massive 90 mm versus the stock 78 mm. The bearing I.D. is increased from 34 mm t0 44 mm. This larger I.D. gives the hub more support in the bearing which controls the large 30"-34" tires. The spindle has a double shear steering arm which will accecpt a 5/8" or 3/4" heim joint. The hubs are available in 7075 billet aluminum, and have a huge 270 mm chromoly rotor with 4 ARP wheel studs. The spindles have a stainless steel brake caliper adapter that utilizes the stock Polaris caliper bracket to accommodate the large rotor. The billet aluminum rear uprights that bolt to the swing-arms also incorporate the large bearing and are pocketed out to except 5/8" or 3/4" heims on the end of the radius rods. Comes with all necessary hardware.