TKI CNC - TOM KOBZA INC billet axle kit (NOW BLACK ANODIZED ONLY) to install 1" taller wheels, so these are called a 1/2" offset axle. These will replace your Ski-doo oem 180mm wheels to 8" or ski-doo oem 200mm wheels to 9". NEw for 2018 these come with REV GEN4 inserts also. These reduce rotating friction by decreasing the bend your track has to make around a smaller wheel. These are machined for 25mm bearings and are patented. Choose rail adpaters at checkout for Ski-doo, Polaris, or Arctic Cat ! all of our TKI CNC axles are now hard anodized black for better finish and durability and cost $10 more than the raw aluminum axles. Order 8" or 9" wheels separately.