2015 JK want to keep stock rims , With Teraflex leveling kit what is the largest tire size I can use?
Will that tire require wheel spacers?
Thanks

 

Without wheel spacers or adjusting the steering lock stop bolts the largest tire you can fit without rubbing the front swaybar is the stock tire size 255-70R18.

I put 265-70R18s on mine with a 2.5" front lift and 1.5" rear lift and I had to adjust steering lock stops by adding two or three washers to keep it from rubbing the swaybar on one side.

 

Really it's the stock wheel that holds you back here because the backspacing is so close to the sway bar. With wheels you can run 33x12s, otherwise get some spacers and you can do 275s. If the tire shop is willing, sometimes you can get them to mount 285s but most won't because it's not within spec on a 7.5-8" wheel.

 

On the flipside, there are meaningful drawbacks to using either spacers or wider wheels. So it really does become a bit of a question of, how important is wider/bigger tires? Because it's not quite as simple as just add a spacer and go.

 

33x12.5 R18 on stock wheels with 1.5" spacers and 2" leveling kit.

 

275/70r18 will fit. It will rub the air dam slightly on full lock. Only BFG KM2s are made in 285/70r18. Anything wider will cause rubbing issues wo spacers. 295/70r18s are an option. A 295 is the widest tire that is spec'd to the 7.5 rim. No tire shop will mount a 12.5 on the stock rim width.

 

Usually local small business tire shops will mount 12.5's on stock rims. That's who did mine, but most large chains won't. Some large chain stores won't even touch your rig if you're running spacers. So support local businesses, become friends with the shop owner.

 

<it's not an air dam BTW ... it' just a plastic cover...> I presume that plastic cover under the stock bumper will rub before the sway bar? I don't know because I mine's been gone a long time.

I will point out that there are differences in actual tire widths. Some tires (BFG for example) run small, in which case you might get a 275 to fit where a 265 of another brand that runs larger (like my Cooper tires) would rub. So I think it's fair enough to say that without knowing the specific brand or model of tire, a 255-70 is the widest tire that won't rub at all at full lock on the stock Sahara wheels with no spacers and no steering lock adjustments. In my case Cooper Discoverer AT3 in 265-70R18 (very close to 33" actual outside diameter) rubbed the sway bar at full lock on both sides with a 1" spacer lift on front and stock track bar, after going up to a 2.5" front lift and adjustable track bar only the left side would rub and it took 3 washers under the steering stop for it to not rub. No way a 275 Cooper tire would have worked on an unlifted Jeep without wheel spacers or severely limiting the steering lock probably beyond what can be done with washers, you'd have to replace the bolt with a longer one with jam nuts.. Also without any lift at all certainly a 275 is likely to rub the fender liner at full compression without at least some lift, although a 1" lift is certainly enough in this case.

Since tire sizes vary and 255s are very close to the limit on stock wheels, it's not safe to assume anything larger than a 255 will fit without rubbing on the sway bars (and maybe that plastic cover).

Also, on my Jeep the 265s are pretty close to rubbing in the rear too on one side (1.5" lift in rear, stock track bar). Your track bar and adjustment front to rear really does affect clearances if you are using the stock wheels with no spacers because there really isn't much margin, and if you lift the Jeep without precisely centering the axle then you may run out of margin on one side. Also you have to remember that when the suspension is flexed the axle moves side to side so you need this margin to prevent rubbing under driving conditions. You can't tell very well by "flexing" the suspension which routinely results in only compressing one side while the other extends, but rather it's when both sides compress the same like as you go over something like a speed bump or the Jeep rolls off of a flat ledge like off a curb or bigger and both sides compress on landing that the axle shifts side to side and it may rub at that moment. It may actually do more than just rub and wind up actually limiting travel and resulting in a pretty harsh-feeling "BANG" when the inside of the tire comes in rapid contact with the frame or control arm.

 

The mopar part is literally called an Air Dam. Google it. Rereading Firecrackers OP they never specify 17 or 18 inch rims. I saw a bunch of 18s in the posts and assumed. Firecracker you'll want to specify what size rim and what you intend to do with her. If you want the largest tire for street use with a level kit, that is one answer. If you are going to have discos and off road aggressively, that is another. I can share my experience with 18s and a level kit. If ur running 17s someone else will have to chime in.

 

He never mentions 18 in the post but did in the title.