2 Answers

There has always been a variant in tire sizes in relation to vehicle size.I suspect that wheel base and perhaps the distance of car body from road surface come into play as well.There are,however,few places that one can purchase 15" tires.They are a rare commodity as so many manufacturers of vehicles have replaced these.Another tire size gone the way of the dinosaur is the 17.5 inch...had to pass on a 1982 Chev half ton due to no available tires in that size.So for a history on tires here is a link to a page full of options and will see if studies can be located>>>>http://www.bing.com/search?q=history+of+tires&qs=AS&form=QBRE&pq=history+of+tires%3F&sc=1-17&sp=1&sk=

I think it's strictly aesthetics. I think their ugly after 16 inches. What side of the tracks your from has something to do with it.