Size is 205/55-16, going on my 2014 Elantra sedan. I have ran the RT43's on the GT, with 17" tires. But there is quite a bit of difference between ride comfort between the 16" and 17". Tire mileage is not much of a concern as the roads down here usually eat them pretty quick. Not much if any snow, hot assed summers, average cold winters, and rainy springtimes. Looking mainly for quiet and all around good handling. The choice is between these two.