I have an 05 auto with the factory 19's. However I want to buy a set of new wheels and winter tires for the long ohio winters up here. I know I definately need to go smaller then 19 and am assuming AI can get away with 17's. Any advice on exactly what size wheels and tires I can get away with for the winter?

Thanks guys!

 

I had been using 17" (7.5" front an 8" rear) with Blizzaks LM-22s 225/50R17 front and 235/50R17. This setup was actually perfect for the past 3 winters in Boston (don't know where you are) and never had a problem even on highways in the middle of storms.
The overall diameter of the set-up was very close to the original set-up with the 19s which means that my car was pretty much at the same height.

Hope this helps.