If all goes well I will be picking up a 2008 SUT in the very near future. It currently has the standard 17 x 8.5 wheels and the tires need to be replaced.

What I want to do is to try to find some of the 20" polished multi spoke wheels and outfit with 325/60R20 BFG K02's here are the difference in the specs between the factory 17 vs the 20 are almost non existance.
Comparision: 17" vs 20"
Sidewall Height: 8.68'' 7.68'' -1''
Section Width: 12.4'' 12.8'' 0.4''
Tire Height: 34.36'' 35.36'' 1''
Tire Circum: 107.95'' 111.09'' 3.14''
Rev. / Mile: 586.94 570.35 -16.59

The speedo error will be less then 1.5% at 60mph which is of little concern. I am curious is there will be any effect on ride quality.

One thing is for sure it will look so much better with the 20's vs the 17 inch rims. I know Hummer did that to keep wheels from getting damaged and allowing under inflation for off road use. Considering other then some
very minor off road use in sand my H2 will never see rock trails. I know it will probably be nearly impossible to find the factory 20" wheels but Im looking now, another option would be to purchase take off's from late model GM 2500/3500 trucks.
Comments?

 

I prefer a higher aspect ratio(more sidewall) =more comfort. Ride comfort is a function of spring and dampening, which can be adjusted from the tires.

 

Hummerz,

You bring up a very good point I did not consider. Rubber flexes and absorbs shocks, metal does not.

Considering I am going from an 06 with rear air suspension to an 08 with springs, there will already be a difference in ride quality with the different suspension.

The 20" wheels on top of that might make we wish I would have stuck the 17's. Sometimes if it ain't broke its best not to screw with it. lol

 

Soft suspension equals comfort...hard suspension equals a trip to the chiropractor.

 

Another pavement queen with 20" rimz, that's what we need.

Rimz do not change your speedo accuracy, but tires do.