I have done exhaustive (and sometimes wasteful) research on 15"s v.s. 16"s v.s. 17"s. The guy at Tire-rack said "go to 17"s, soon there won't be any 15" tires being made". He also said that 16" were probably going to disappear, too. Low demand he said. Well, I happen to be among the tiny minority that doesn't like the "look" of 17", although I yam NOT a rivet-counting authenticity-fiend!
I just happen to like the higher-aspect-ratio tires. It's too bad the BIG-LETTER
Goodyears don't seem to be streetable or less prone to vacuum up all flingables off the road-surface and sand-blast your finders, etc.
Paul, et al, was also right about the thread-depth on Thompsons, good for one exit of your driveway and one trip down-town.....