not sure what dictates the size of o.e.m tire/rim sizes. thirty years ago the average car,pickup truck had 14" rims with 78 series profile of tire. not sure but i think the mini came with 10"rims. fast forward to today. generally speaking the average is 17" rims with a 50 series profile tire. some vehicles are coming from the factory with 20" or larger. is it purely asthetic's,cost, or engineering that has dictated this trend. what do you think the future will see.