I got new tires a couple of weeks ago and after 500 miles they are riding better and I got better mpg on the 2nd tank. I went to Ecopia Plus 185-55-15 tires on a 6.5in wheel. I was getting 41.5 mpg with the Ensaves. The first tank wasn't great wi the larger wheels. I added a bit more air 38psi, and the second tank was at 39.5 mi/gal with the new wheels and tires.