What "ride quality" difference will I notice when going from 18" to 20" wheels? I do a lot of highway driving.

 

There is a little degradation in ride quality, but I barley notice it. If you are going over a large pot hole or something like that you will notice it is a little bumpier. Other than that, you won't notice much at all.

 

With a 20" wheel you have to go with a very low profile tire (30 or 35 series) in order to maintain the stock ~27.1" tire O.D. Due to that, you reduce the amount of sidewall and thus the amount of cushion the sidewall typically provides. Since you drive highway you'll probably be ok but any rough roads will be harsh. Also, a pothole that you might only wince at with smaller wheels are potential rim busters with 20's. Also, 20's tend to be a bit heavier and add some rotational mass but you may or may not notice the loss of performance.

Of course, I have my own personal opinion about wagon wheels with rubber band tires... I mean, 20"ers with low profile tires... which I won't get any farther into.

 

i did not notice that much of a difference, though I only changed my to get a wider back tire, 10.5, and found it difficult, at the time, to find one with a sufficiently wide back tire. Are you going for just the apperance view or trying to get a different size for the rear?

 

Mine changed very little but my tires 255/35 and 275/35 20 so there is still a fare amount of side wall!

 

Uhhhh, no. Not even on my 40's. Not even on my OE 50's. About 60 series you're beginning to see some MANLY sidewall.

 

You will see a bit of a difference, but NOT as much as some would say.

Nuke I usually agree with you, but in this instance I do think it is the evolution of cars/wheels in general. Think of it this way, most original (classic) stangs came on 14's. That what the car was designed for. You run 18's which is far bigger than those classic stangs of yester-year. Look at most muscle cars today:

1. Mustangs; a lot come with 19's, bet you the next gen will come with 20's.
2. Camaros come on 20's
3. Challangers; quite a bit come on 20's

I would say at this point the 18 to 20 inch range is probably the norm for sports cars. It really is personal preference at this point. I'm not trying to convince you Nuke.....LOL, just some provocative thoughts!

PS My first car in the 80's I went from 13's to 14's & I thought they were HUGE.....LOL