Hey I have a Lincoln mark lt 2007 with stock 20 in. rims and I want to put a slightly bigger Tire on them to fill my wheel well more . right now i have 275/55r20 nito grappler.

Does any one know what the best option would be to go bigger ?

I was told by a tire shop that you didnt have to put any lift on the 285/65r20...... but what about even a 295/55r20 or 305/55r20??????
is this true

will the tire rub... and will it mess with my gas mpg, and speedometer....

thanks