Going to 315/70/17 tires on Willys JLU without "major" suspension modifications?

[Willys_Wonka]

I'm considering jumping to 315/70/17 from 285/70/17 on a Willys JLU. Has anybody done it w/out adding "major" suspension modifications, pictures are appreciated? Only mods this far are Rubicion springs, which boosted ride height about 1.25". Mopar LCA's are also going on and I would probably install .75"-1" coil spacers after the larger tires are mounted for more wheel well clearance. From what I gather, the only rubbing expected is the sway bar, but simply adding a 10mm washer to the steering stops (2) should rectify that issue. I was going to just increase to 285/75/17, but 315/70/17 really grabs my attention. Current set up below and I would keep the OEM 17x7.5 wheels for the 315 tires.

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[Wabujitsu]

I can’t say you will or won’t have rubbing, so I won’t speak to that. On my previous Sport JLU with a 3.5” lift I had no problem with 35s, even with sway bar disconnected and at full flex.

You may find some shops won’t install those tires on a 7.5” rim, but generally off-road shops will do it with no problem. Make sure you drop the PSI enough that the edges of your tires have sufficient contact with the road; the narrower rim will cause the center of the tread to bulge at recommended pressures. I run mine at 28 PSI cold, 30-31 hot, and I’m getting even wear (Falken Wildpeak 35x12.50 MTs, load range E). Many well-intentioned folks will tell you it’s a safety hazard to run oversized tires on narrow rims, but the only danger is uneven tread wear and thus shortened tread life of the tires.

 

[Willys_Wonka]

I can’t say you will or won’t have rubbing, so I won’t speak to that. On my previous Sport JLU with a 3.5” lift I had no problem with 35s, even with sway bar disconnected and at full flex.

You may find some shops won’t install those tires on a 7.5” rim, but generally off-road shops will do it with no problem. Make sure you drop the PSI enough that the edges of your tires have sufficient contact with the road; the narrower rim will cause the center of the tread to bulge at recommended pressures. I run mine at 28 PSI cold, 30-31 hot, and I’m getting even wear (Falken Wildpeak 35x12.50 MTs, load range E). Many well-intentioned folks will tell you it’s a safety hazard to run oversized tires on narrow rims, but the only danger is uneven tread wear and thus shortened tread life of the tires.

It’s seems 285/75/17 is the best option since it’s close to the same diameter as the 315, but not as wide. I’m not thrilled about having to pressure down on 315 on a 7.5 wheel that much.

 

[Wabujitsu]

It’s seems 285/75/17 is the beat option since it’s close to the same diameter as the 315, but not as wide. I’m not thrilled about having to pressure down on 315 on a 7.5 wheel that much.

Understood. Go with what you’re comfortable with. You can find brands that carry 35” tires that are much narrower than 12.5”.

 

[Willys_Wonka]

Understood. Go with what you’re comfortable with. You can find brands that carry 35” tires that are much narrower than 12.5”.

Oh, really? I didn’t know that, such as what brands..I thought once 35” is considered its pretty much 12.5” and up.

 

[Wabujitsu]

Oh, really? I didn’t know that, such as what brands..I thought once 35” is considered its pretty much 12.5” and up.

Nitto, for instance. Just Google 35x11.50R17. Here’s one link: https://www.discounttire.com/fitmentresult/tires/size/35-11.5-17

 

[COKENOGOOD]

I dont worry about the width of the rim but the offset.
you will have a little rub at tie rod &swaybar link when at full turn

it would be better to get wheels with more offset.

 

[Willys_Wonka]

Nitto, for instance. Just Google 35x11.50R17. Here’s one link: https://www.discounttire.com/fitmentresult/tires/size/35-11.5-17

Some run 305/70/17, it’s slightly more width than 285/75 but same diameter.

 

[Wabujitsu]

I dont worry about the width of the rim but the offset.
you will have a little rub at tie rod &swaybar link when at full turn

it would be better to get wheels with more offset.

Hugh, good point!

I went with 2” wheel spacers on all four corners, for that reason. A rim with a proper offset is preferable though (no potential scrub radius issues).

 

[Willys_Wonka]

Hugh, good point!

I went with 2” wheel spacers on all four corners, for that reason. A rim with a proper offset is preferable though (no potential scrub radius issues).

I really don’t want wheel spacers, so the 35x11.5 is very interesting on my 17x7.5 wheels. More than likely, I’ll use coil spacers for some added boost. I could probably stick 35’s in as is, but I want more clearance. From what a read, just adding a washer on the steering stops should avoid any rub on the sway bar. It’s a 99% daily driver, so I’m going for aesthetics but safely.

 

[Willys_Wonka]

I dont worry about the width of the rim but the offset.
you will have a little rub at tie rod &swaybar link when at full turn

it would be better to get wheels with more offset.

Another thing is in PA, tire poke is not permitted. I need to stay within the fender flares or add extensions.

 

[Wabujitsu]

Another thing is in PA, tire poke is not permitted. I need to stay within the fender flares or add extensions.

That is also a great point! I forget about that, because it isn’t an issue here in Florida.

 

[Rubi II]

I can’t say you will or won’t have rubbing, so I won’t speak to that. On my previous Sport JLU with a 3.5” lift I had no problem with 35s, even with sway bar disconnected and at full flex.

You may find some shops won’t install those tires on a 7.5” rim, but generally off-road shops will do it with no problem. Make sure you drop the PSI enough that the edges of your tires have sufficient contact with the road; the narrower rim will cause the center of the tread to bulge at recommended pressures. I run mine at 28 PSI cold, 30-31 hot, and I’m getting even wear (Falken Wildpeak 35x12.50 MTs, load range E). Many well-intentioned folks will tell you it’s a safety hazard to run oversized tires on narrow rims, but the only danger is uneven tread wear and thus shortened tread life of the tires.

I’ve been looking at those tires, have the 285’s that came with my Jeep and have liked them but they are load range C. How is the ride and noise on 35’s LR E? Considering getting 315’s A/T’s with load range C but do like my 285 M/T.

 

[Wabujitsu]

I’ve been looking at those tires, have the 285’s that came with my Jeep and have liked them but they are load range C. How is the ride and noise on 35’s LR E? Considering getting 315’s A/T’s with load range C but do like my 285 M/T.

Good morning, Mike!

At about 28 psi cold, 30-31 hot, the ride is perfect! I was skeptical of LR E too, but now I’m a fan. Presumably, with lower PSI, it allows the sidewalls to “work” - to flex and help absorb bumps, etc, on and off-road. By the way, I don’t air-down when we go off-road, even on extremely challenging trails.

I and my wife are quite comfortable, and we are both disabled, with spine and other issues.

 

[Wabujitsu]

I’ve been looking at those tires, have the 285’s that came with my Jeep and have liked them but they are load range C. How is the ride and noise on 35’s LR E? Considering getting 315’s A/T’s with load range C but do like my 285 M/T.

Mike, I forgot to add this: MTs are always going to be louder than less aggressive treads. However, I find the Falken Wildpeak MTs to be surprisingly quiet, but that WILL change over time. They will become louder as the tread wears down.

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