I just purchased a set of the 214 style 20" wheels for my 4.8i e70. Previously, I was averaging 15mpg in the city and 19mpg on the highway. I pressurized them to 37 rear, and 36 front, and am seeing a 5mpg reduction, so now average about 10mpg city and 14mpg highway.

Is pressure to blame for this huge reduction in mileage, or is it just the wheels? EPA spec with them is supposed to be 14/17, so I thought I would end up somewhere pretty close to there. I don't drive with a lead foot, and it's still pretty bad.

Can someone tell me what they usually inflate theirs to, and what your mileage with the 214 style sport rims usually averages?

Thanks a ton