We are putting together a laydown kart to be race ready and we are trying to decide new wheels. Most say to run 6″ wheels at least in the rear, but I’ve heard many different opinions. We are considering 5″ all around, but I’ve been told it may not be advisable. We are running Yamaha Sportsman also. I’d like someone to break down the advantages/disadvantages, and the handling characteristics.
Most of the Laydown guys I know are using the Hoosier 10.5×4.50-6 Enduro Tire on front and rear. The tire seems wider than most 5.0 wide tires and being a sportsman it is plenty of tire to hold the kart. I would mount them on 6″ wide wheels. I have used these at Daytona as well as Hallett, those are two completely different tracks and this setup of tires works great. The controls and opens are using wider tires on the rear.