I have 225/40 18 which I like & 275/30 20 rears
which I would like a bit more profile, actually would like to cram as much rubber in there as I can.
I think the 20's would look sweet if allowed to fill the space.
I keep reading about keeping the same circumference, but cannot find why.
I've put bigger tyres on other vehicles, mostly trucks, w/ no perceived issues other than a better/comfortable ride.
What will really happen by increasing the circumference on the rear?