Actually, the tires (and specifically their width) have a huge impact, moreso than the weight. Wider tires produce a lot more friction and drag. You'll notice the EX with the Premium package, which has the same weight and features as the Touring other than the tires (it uses the narrower ones from the LX) gets the same fuel economy as the LX rather than the Touring.Well, it should be slower as it weighs more, but those figures are suspect. The tires will hurt your mpg, but not that much compared to the couple hundred pound or so penalty over the FE trim.
They do. But the larger the rim, the smaller the sidewall. The smaller the sidewall, the wider the tire, in order to increase the contact patch. The larger the contact patch, the more friction between the tire and the road, and more rolling resistance.I thought I read that they had the same outer tire diameter with the different rim sizes?
Based on the EPA rating, the width of the tire is in fact the only drag on fuel efficiency here. The Touring and the EX with the Premium package would have the exact same weight as the only difference in spec is the wheel and tire package. And a drastic difference in fuel economy, much more drastic than the MPG difference between the loaded EX and the lightweight FE trim.The width of the tire is not the only drag (sorry) on the fuel efficiency.
The lower the tire profile on a car, the wider you make the tires. This is to compensate for less compression available on a narrower sidewall that would otherwise widen the contact patch just from the car sitting on the tires. You may know physics in general, but you have a few things to learn about their practical application in the automotive space.The width of the tire is only one factor at work here. Another one as I stated is the tire profile. Last one is that this tire was not designed for efficiency in the way that it was constructed, belts and materials used versus the Michelin OEM for 16" wheels.
You have an odd idea of how profile affects tire width. It is independent of width and multiple profiles are available for the same width for cars. Ever look at truck tires? They are certainly not low profile. What about earth moving tires? Some of those are as wide as entire cars, and extreme high profile.