Excellent question. If you're also popping for new Kawasaki Mule wheels, it is important to get ones that are the correct bolt pattern. Know that most Mules use a 4 x 137 bolt pattern, while Mule PRO models use a 4 x 156 pattern. The old children's song which told us that 'one of these things is not like the other' is very appropriate here. It can be tough to tell the difference between these two bolt patterns, especially on their own, so double check fitment before withdrawing the cash from your bank account.