Tire Size Calculator
go there, and scroll down. you can look at tires bu outside diameter. i would get tires close to stock tire diameter for clutching reasons. though im not sure on how much difference in weight there is.
2013 Sportsman 850XP H.O. EPS Touring - Blue Fire
Polaris 2500lb Winch W/ Syn Rope & Auto Stop, Heated Hand Grips, Heated Throttle Kit, Handguards, Mirrors, Storage Boxes - LED Headlights, ATV-Guru Cobra Front Bumper, K&N, NGK Plugs, Ricochet A Arm Guards, Ricochet Floor Board Guards, 60" American Eagle Plow, Worklight Mod, GoPro Hero 3, Polaris LED Headlight Upgrade, Custom Reg Decal Plate.