You might want to rethink your tire size choice if you're concerned about MPG. The Goodyear Assurance Fuel Max tires are good tires. You'll get more life out of them as well.
The foot print of 235s will be wider creating more drag not to mention, as you've said, you lose MPGs cause the tire is smaller. When driving 60 MPH you'll actually be driving 57.8 MPH. Those
Here's a tire size calculator.
Tire size calculator
If you're after performance then I think it's a step in the right direction to keep you from lighting up the tires and it's like reducing your gear ratio a little.
The foot print of 235s will be wider creating more drag not to mention, as you've said, you lose MPGs cause the tire is smaller. When driving 60 MPH you'll actually be driving 57.8 MPH. Those
Here's a tire size calculator.
Tire size calculator
If you're after performance then I think it's a step in the right direction to keep you from lighting up the tires and it's like reducing your gear ratio a little.
