A good guideline is that a rider seated on a bike should be able to place both feet flat on the ground while not standing up. They need to additionally be able to handle the weight of the bike without difficulty. Talking with several dealers can help you make a better decision as they will usually have the experience necessary to give you some smart guidance. Will you use your dirt bike for racing or recreational purposes?Depending on what sort of riding you intend on doing, the k...