This TKI CNC - TOM KOBZA INC- Billet offset 4 wheel axle kit (Now anodized black only) will allow a 1" larger wheel than your stock wheel . For example: SKI-DOO oem 180mm or 200mm wheels can be changed to 8" or 9". This reduces rotating friction by allowing the track to bend less as it rotates around the rear skid wheel. These are machined for 25mm bearings and the wheels must be ordered separately. All of our wheels have 25mm bearings included. These are a great addition to Ski-doo's Freeride 137 and B/C for riders who run trail more than powder and gives a little extra security to make it home as the 2 wheel axles have ruined many a trip. These axles come with rail inserts for Ski-DOO, POLARIS, OR cat-CHOOSE AT CHECKOUT. All of our axles are hard anodized black for durability and cost $10 more than raw aluminum . Oversize wheels do not fit on SKI-DOO 120-129" without modifications. Order 8" or 9"wheels separately.