Oversized Tires: 472-DPPSOBL. The stock 800 EFI comes with 26 inch tires. If you choose to switch to heavier, more aggressive 26” w/10” wide fronts and most 27” tires, the 800 will perform better by simply adding our Orange/ blue (part #472-DPPSOBL) primary spring. For all 28” and up tires use complete kit (Part# 472-DP800EXT) - We simply prefer to not sell you more than what you need. Extreme Tires: DP800EXT Extreme mud tires. This clutch recalibration kit is designed for the serious mud runners and those using larger aggressive mud tires, (28 inch and up). For use on stock machine. May cause slight loss of top speed.