For a 2006 model, 26" tall will work without a lift........most 27's will work without a lift.......28's will require a 2" lift in the front. Keep in mind that this info' is for the true O.D. of the tire. Some tire sizes run larger or smaller than their listed size. For example my 27" Bighorns are actually about 28 1/4" when aired to 14 psi.
Wheel offset also factors into how wide you can go. Check the clearance between the tire and the tie rod end on the front, and between the tire and the swaybar in the rear. If you have 1/2" or more clearance, you can go to at least a 1" wider tire. If you have over 1" of clearance, you can go with a tire that is 2" wider.......etc...
If you want to run a wider tire than your present clearance allows, you'll need to install spacers or get aftermarket wheelsd with more offset. Just FYI.......running 27" Bighorns (28 1/4") required a 2" lift and the use of aftermarket wheels.
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