It was the 18 inch base tire on a (2010) G.T. compaired to the optional 19 inch (not the track pack summer only) tire. I would think both sizes were 'all season'. After reading the test, if i had bought a 2011 G.T. i was going to go with the standard 18 inch wheels and tires. I wish i could remember where i read this test.

 

Oops! Forgot about the diameter of the wheel increasing too. But the diameter of the tire wouldn't. Maybe it weighs the same or more because it has to support that weight with less sidewall? Heavier duty sidewall construction? Higher performance rating?

 

Actually VW's have gotten quite a bit heavier over the years since I owned my 2000 lb '83 GTI. The 2010 Golf C&D used for their test has a curb weight of over 3k lbs, of course it is still about 500 lbs lighter than a Mustang and FWD.

There is usually a sweet spot for most cars for choosing a wheel/tire diameter, for S197 Mustangs that seems to be 18", for SN95's, 17". This is taking into account appearance, tire availability, performance, weight, NVH, etc. For example, there are very very few summer only high performance 17" tires in suitable sizes for S197's, but a lot for SN95's due to the earlier Mustang's smaller OD tire size. Some people like the looks of a 19" or 20" wheel/tire

I'd rather stick with 17" wheels on my '08 GT, but I'll be switching to 18's (already have the wheels, still deciding on tires) due to the lack of any really good 17" tires in anything close to the stock tire outside diameter.