A few months ago I changed tires on my WRX from the stock Bridgestone which had lasted nearly 40K miles to Bridgestone 950's. The difference in both ride, noise and handling was night and day compared with the stockers. However, immediately following that my gas mileage dropped from 20.4 to
17.8 even though my commute trip of 60 miles remained identical. My measurements are very accurate as I fill up at the same place at about the same time of day, and have kept accurate records since I bought the car new. I have had the dealer check it over and there was nothing wrong, so it has to be the tires. The new ones definitely feel "stickier", and I even have them at 2 psi over the recommended pressure so I would not have thought that the stickier rolling resistance would have had that effect, but it sure seems it does.Has any other owner experienced this phenomena?