There are basically three types of wheels from which you can choose: racing slicks, street tires and off road knobby tires.

Racing slicks are for, well, RACING!! They're ideal for a perfectly paved dry track that is well maintained. Racing slicks are terrible for performance on any rough surface. Racing slicks are made for go carts that run on a track.

Street tires can be purchase in all shapes and sizes. In this regard, a go cart is a lot like your car. Street tires perform okay on basic off road environments like dirt roads and high traffic trails. Street tires provide the most consistent performance over a wide variety of surfaces.

Knobby tires are ideal for extreme off road carts as they are great for traction in loose dirt, gravel, and mud. Normally, knobby tires come in almost any size ranging from 3.5 inches on up 16 inches. Yes, they do have bigger knobby tires. However, it's important to remember that the bigger the wheel the more power required to move it (unless your go cart has a transmission). The go carts that have transmissions are almost unlimited by the tire size.