Tire size for JKUR

[TRevs]

I got my son a stock 2014 JKUR a year ago and decided it needed a lift and tires. I'm putting on a mid-level 3" teraflex kit now, and it will be ready for bigger tires soon. i'd like to get it around 35's with no plans to go bigger or re-gear from 4.10s. I also want to keep the factory wheels which are I believe 7.5" wide. I'm ok with 1.5" wheel spacers.

Some manufacturers sell All-terrains in both a 285/75x17 and a 35x11.5 x17 (BFG TA KO3, Yokohama Geolandar X-AT). The metric versions are only a few mm smaller, and somewhat cheaper.

Is there any signifcant difference? If not, why do they make such similar tires in the virtually the same size?

 

[GATORB8]

I got my son a stock 2014 JKUR a year ago and decided it needed a lift and tires. I'm putting on a mid-level 3" teraflex kit now, and it will be ready for bigger tires soon. i'd like to get it around 35's with no plans to go bigger or re-gear from 4.10s. I also want to keep the factory wheels which are I believe 7.5" wide. I'm ok with 1.5" wheel spacers.

Some manufacturers sell All-terrains in both a 285/75x17 and a 35x11.5 x17 (BFG TA KO3, Yokohama Geolandar X-AT). The metric versions are only a few mm smaller, and somewhat cheaper.

Is there any signifcant difference? If not, why do they make such similar tires in the virtually the same size?

I'd just stick 12.50s on them, as it's barely outside of rim width range... but to your question.

There is more than just size to consider.

For example, in KO3s, the 285/75 is an E load, it's actually smaller, heavier, and has deeper tread. The 35x11.50 is a C load. They also have different speed ratings.

In my experience, you can get past some of the ride issues with running a heavier load tire than you need with running the proper air pressure. The sidewalls tend to be a little more durable in a heavier tire as well.

In general, a C load LT tire would be spec'd for a half ton truck, and an E load would be spec'd on a 3/4 ton. C is more than enough for even a super heavy JK/JL build.

Flotation tire sizes are very rarely used by OEMs anymore. The 285 is likely a replacement (or one size upsize) for a heavier truck, the 35 is meant for people looking to upsize to 35" off road tires.

The KO3s:

 

[GATORB8]

I'm far more experienced with the JL, but the JK tends to be fairly similar.

Teraflex specs a maximum backspace of 4.75" on the ST3 3". Factory JK wheels should be the same as JLs at +44.5 mm offset on a 7.5" wheel, which is 6" of backspace. Unfortunately, I believe the JKUR axles are the same width as the standard ones.

Normally your rubbing issue will be in front on the lower control arms if you are running too much offset, so you'll likely need the 1.5" spacers you mentioned in order to maintain lock to lock steering. There may be a chance that you could limit steering angle by backing out the stops on the knuckle, but that's a lot of distance to overcome with that method.

 

[rasband]

My only thought is for a non-wheeling focus (which I interpret as a desired look with street ability being important), I'd heavily consider the weight penalty as it's the most impactful metric around a circle for both getting to speed, maintaining speed, and stopping (rotational inertia).

 

[GATORB8]

Side note, 35s are a relatively common "oops" size for a JLUR before a change to 37s. I wouldn't be surprised if you could score a low mileage set on FBMP pretty easily. Bolt pattern is the same if you can find a combo as well.

Unfortunately I learned it the hard way, and someone got a steal on a 2 month/3k miles set of KO2s.