ATR’s Polaris RZR Chassis Ribs add strength to the rear of your chassis by bracing the sides of the chassis together with the existing factory holes and by also tying into the upper and lower A arm mounting points. The Chassis Ribs are CNC laser cut from 3/16″ steel plate. For the upper A arm mounts instead of simply welding a washer to a chopped tube like some manufactures may do ATR CNC machines a stair stepped end piece that centers itself inside the tube, and provides the perfect gap for a nice flush TIG weld. Chassis Ribs come in a durable black powder coat finish and can be purchased in our store for $115