Our 8" Big Wheel Kit converts your 7" MXZ, Renegade, and Freeride R-motion rear idlers to 8" which eliminates more rolling resistance and gives a wicked look. Sleds with the stock 2 wheel rear axle also benefit with this 4 wheel kit on trail with improved roll control and cornering with the ability to pop the outer Big Wheels off for powder riding. The center wheels stay tight and you can throw the two outers in the trunk. The other benefit is the security of having 4 wheels to get you home vs. stranded as just one wheel failure with the stock 2 wheeler and the party is over and the weekend done with a broken wheel. The kit pictured is on a 2015 Freeride 137 R-Motion. These now come with inserts for the 2017-2020 GEN4 chassis. The axle is available in anodized black or silver billet aluminum with Avid Wheels. Sold as a complete bolt-on set. This fits 137" skids and It will not fit 120" , 121" skids. Customers report that it can fit a 129" with some adjustments/ modifications and a track with some miles that has stretched from brand new but is not a simple bolt-on.