As mentioned in another thread, the stock tires on my ’07 JKU are P255/75R17.

On my stock suspension- and without requiring wheel back spacers- which replacement tire would fit best on my ’07 Sahara Unlimited:

An LT285/70R17 or an LT 255/80R17?

Other than affecting the speedometer/odometer, would either of these tires require any other adjustments or modifications?

 

I run LT285/70/17 Mud KM2 on stock moab wheel no lift, no wheelspacer on a 2dr 09JK.

With no wheelspacer, expect to rub on the swaybar at full turn, there is a write-up on how to fix this by modifying steering stops( easy 10min mod)

 

You realize that a 4.25bs is equal to a 2" wheel spacer, right??? You can't compare your setup to running those tires on stock rims...


OP - NOBODY can tell you 100% that you will or will not have issues. Get the tires you want and deal with the issues if/when they happen. Add spacers, get new rims, bring in the steer stops, add a small lift, chop your flares, etc.

 

Interesting. I was hopefully that a couple people of the 40,000 participants on this JK Forum might be able to offer some insight on these tires based on firsthand experience. Perhaps I'm wrong. My bad.

 

You should not have any problems running the 255/80-17 on your setup in stock form (stock rim, stock backspace.) From what I've seen of mine, a 255mm (~10") width tire up to 34" or 35" would work with little to no contact. The problem comes from tires being too wide an rubbing on suspension components, particularly the swaybars. The 285/70-17 will give you such rubbing issues unless you install aftermarket rims with less backspacing or use spacers.

I've been running the same overall size on the 16" rim (255/85-16) for just under a year and have yet to see any rubbing with it until the rim change in September. Never a rub or issue with the stock rims. Still no rubbing off-road, only on-road with the new rims (16x8, 4" backspace.) The tires will kiss the fender flares on hard compression in city driving. Very rare and so far only happens in one area that fully compresses the suspension (side road, looks like they paved over a small drainage creek.)

Additional advantages of the 255 include a weight savings and better road manners. Off-road in most conditions they'll excel over the wider tire. I've yet to disconnect my swaybars out of need and I do not have lockers. While I haven't run anything as serious as the Rubicon Trail, I have had it in some nasty places. That was mainly during my trip up to Kentucky in August of this past year. No issues and I ran more than one of the "green trails" (expect damage, heavily modified vehicles, etc.) with no real issues. I'll be running this size until BFG makes a 35" tall MT with a 10" to 10.5" (maybe 11") width.

 

Think about it. There are far too many variables involved. Simply changing the psi from 28 to 35 or 40 or 50 will affect the tire height. Are the steer stops the exact same on every single JK right from the factory? How about the difference between a 2 and a 4 door? The 4 door is heavier, more weight on the tires, less actual height. What if the person giving you a recommendation has a small lift, and his axle is shifted over? Or he has aftermarket links? Or whatever. As noted above, you have someone with an effective 2" wheel spacer advising you that you won't have any issues!! Nobody is going to have your 'exact' setup, they can only base their opinions on their own individual setups...