[quote author=HeaTransfer link=topic=70955.msg1248747#msg1248747 date=1173067895]
- the 225s are shorter than stock so shorten the gearing, which decreases fuel economy. You will notice that a 225/45/17 is also "shorter" than stock.
- the 225s are wider and are a much stickier compound.
- I probably drive harder on the 225s.
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225/45R17 is actually the same diameter as the stock 205/50/17, so you won't have any difference in gearing. I do agree that wider tires and a more high performance, stickier compound can have an effect on mileage, and more so if you drive harder on the better tires.
I went from the stock Goodyears to Max Performance 225/45ZR17s, and I haven't noticed any difference in gas mileage. Of course, it's appropriate to add, YMMV!
In the end, I wouldn't let gas mileage sway your choice of wheels and tires, as the effect on mileage from just changing to the wider tires will not be drastic. There were probably other factors that caused you to have much poorer mileage with your Volks.
EDIT: corrected tire size