Locking Hub Conversion Kit for Jeep XJ, YJ & TJ Dana 30 front, 5 x 4.5" bolt pattern. The Yukon worry free Spin Free Kit replaces the vulnerable and expensive factory unit bearings with tapered bearings and races. The result is not only a design which is easier and more economical to service, but one that offers significant increases in mileage per gallon. This hub kit also includes WARN locking hubs, giving you more driving selectability. Locking hubs allow for installation of a mechanical locker in the front without the negative affects while driving on the street. This kit includes wheel hubs, rotors, spindles, high strength Yukon 4340 Chrome-Moly outer axles, WARN locking hubs, Timken bearings, high quality seals and all hardware for installation.