I have a 2011 sahara with 18 inch wheels, if i were to get 17s what size tire would i need to get to avoid reprogramming and lifting. Thanks

 

The same size. Say if your running a 32 put another set of 32s on it and you will be fine.

 

You would just need to get tires that fit a 17" rim. Tires have three basic measurements: Section width, ratio of sidewall height to section width, and wheel diameter in inches. These measurements are in mm. Tires can also be measured in inches...for example a 33X12.5 R17 is a 33" in tall, 12.5" wide tire for a 17" rim. Basically pick whatever tire you want (probably < 33" if you want to prevent lifting) so long as if fits a 17" rim.

 

But would changing tire size mean reprogramming or could i match the old wheel and tire combos height somehow?

 

A 32x12.5 R18 is exactly the same height and width as a 32x12.5 R17 the only difference being the rim size. So in your case if you look at the sidewall of the tire and get the dimensions, you can go buy the same size tire for a different size rim. Honestly a slight change in size like +/- an inch or so probably doesn't require a recalibration since it's not a big difference.

 

I think what he might be asking is not so much the diameter, but the aspect. For example a 245x75x17 is approx. 31.47" in diameter, whereas a 245x75x18 is 32.47" in diameter.
If that is the case, for every inch of the wheel size, provided the tire aspect would stay the same, one would add an inch to the overall diameter.
WOW, I just confused myself on that one.

 

We may be able to help you more if you posted your current tire size 255/70/18, or something similar. That way we could give you an accurate answer on the closest tire size for a 17.

 

Wow, thoes answers were confusing.

255/75 17

That is the factory size on Rubicons/Sport S. No rubbing, no reprograming, no lift, no spacers needed.

Backspacing on rims is a seperate issue, your tire shop/online vendor can find wheels with backspacing similar to factory rims. Improper backspacing is why you see busted cars with rims that stick out 4 inches past the fenders. Improper backspacing on your Jeep could lead to tires rubbing.

 

Exactly what i was asking, thanks for the help.