Hey yall ive got a 92 dually with 235/75/R16's on it now. Im putting a 4.5 in lift on this thing and i was wondering if anyone knew how tall i could get the tires before they are wide. In other words whats the tallest tire, with a width of 85? Im not planning on towing with this or anything.

 

tirerack.com
You can search their tires by several different filters.
Link below shows a LT255/85/R16 tire
Tire Search Results

 

Do you have enough power & gears for the bigger tire, this a stock 6.5 ???

 

85 isn't the width 235 is in millimeters

 

Very true, the "85" is the ratio of tread width to sidewall height. I just assumed he wanted an 85 profile tire.