Any guys here switch from 18 to 19 inch wheels. Did you notice any difference in anything? I'm sure you like the look.

 

i went from 81s to 19s but am hanging on to the 18s for the track. i did it for the look. they definitely fill out the wheel wells. what i did notice was the increased amount of bump steer but i got used to it. the steering feel also was a little more vague. doesn't bother me at all. i did NOT notice an increase in ride harshness but i drive on mainly smooth roads so YMMV.

 

19s filling out wheel arches better than 18s is an old wives tale........basically same rolling diameter.
What 'fills out' wheel arches is offset and ride height.
Fixing both of those (and then using a flat lip reverse drop rim on an 18) will look every bit as good as 19 and not be more durable as a 'daily' than 19s.......I like 19s, have em, will continue to fix them when I bend them......always will track with 18s.
Picking new wheels is fun....research wisely.....good luck to ya.

 

NOT an old wives tale. 19s have a full inch in diameter which "fill" out the wells. i believe this is what the eye picks up not the tire. FWIW, the rolling diameter fo my 19s is almost a 1/2" bigger than my 18's so when you look at the rubber then the 19's also fill out the wells more.

 

Whatever.
But, just using the turbo #s cause they're handy here........diam of 225/40 18s is 25.09" on 8Js and 235/35 19s on 8.5J rims is 25.48".........in the rear 295/30 18s on 11Js roll @ 24.97" where the 235/35 19s om 11Js roll at 25.2".

I'm sure there may be exceptions & each tire has it's own specs (only the wheel dia & width are givens) but in my case & most cases I've seen....... my eyes are not good enough to see 3/8" dif in diam (but I'm getting old )

Example.....the 18s on this car below 'fill out' the wheel arches OK.

 

Average fitments for the 996 cab as well as average heights:

205/50-17 25.1
225/45-17 25.0
255/40-17R 25.0
265/35-18R 25.3
285/30-18R 24.7
225/40-18 25.1
235/35-19 25.5
275/30-19R 25.5

On average a tire can vary from this about +/- .2" depending on mfgr.

 

225/40/19 and 285/30/19 will most certainly have a larger diameter than a 225/40/18 and 285/30/18.

You have to keep the same width and aspect ratios to make the comparison.