http://www.trailer-wheels.com/ This place has a large wheel selection. You can increase the diameter of your wheels, but you will need to lower the profile of the tire in order to keep the overall height of the tire/wheel assembly close to the same height of the 14" stock tire/wheel assembly. If you install a taller assembly you will reduce the clearance between the tire and the fender which can be a problem. The issue you may run into with trying to go to a larger diameter wheel with a lower profile tire is that the lower profle tire will need to be wider than the stock tire to maintain the same load capacity. If the tire is too wide, it may rub against the inside of the fender skirt or stick too far out beyond the edge of the stock fender.