I bought my 2011 Golf TDI used and it came with aftermarket 18" wheels and Falken Ziex tires in 225/40/18. At first I was dissapointed with my mileage, averaging about 35 mpg. Then I put my winter setup on, oem 16" VW alloys with 205/55/16 Michelin X-Ice and now I'm getting 40 mpg and up. So now...