I went from 32mpg in my civic Si with 195/60r15 winter wheels at 30psi to 29mpg with 215/60r15 tires at 32psi (though going from 30 all the way to 42psi didnt change it much) .
I drive mostly cruising around 50mph but there is about 1/4 to 1/2 city driving, I'd say its a pretty good combined.
I've got a different set of winter tires, same style but 205/60r15 and have them up to 45psi, so we shall see on that, though, its an unfair test because I am also running now a raceheader and I've changed my rear wing to act as an extended decklid instead of a downforce/drag creator
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