I also replaced the original tires with Goodyear ReponsEdge tires, and also lost mpg - from 38.5 to 35mpg. The original tires were rated as lousy at hydroplaning, which is a real concern here in the Northwest where water is frequently flowing across the road during winter.

This weekend I checked air pressure, and the tires were down to 27 psi. Yeow! How'd that happen? 40 psi got me back to 35 mpg, but with a more jittery ride. 37 psi might be best, with much more frequent checks on the psi.

It bugs me to lose the mpg, but the ResponsEdge tires have such a great feel. The car seems much livelier. Pretty expensive, though, and it's a tire expected to last about 30k miles, if I remember correctly. I might go back to the ComforTreds I had on my old Toyota, or their equivalent, when these wear out. They had a nice ride, great wet traction, and many more miles of life.

Soon I'll switch to the "ice" tires I bought for ski trips and occasional frozen roads here in the lowlands. Probably lose another bunch of mpg. Or maybe not.

Ya know, 35 mpg with a car like the TCH isn't bad at all, really. I wanted a bigger car, but didn't want 22 mpg. This car I like.