New tires tend to drop mpg just because simply, they are slightly bigger (not worn) and causes your speedometer to read off. In this case, it's saying you didn't go as far as you actually did. Case and point, my Camry says 60 but I am usually going 63-64 according to the GPS (with a 10-30 ft. margin of error).
__________________
1988 Honda Super Cub 50cc
|