2dr Rubicon tire question

[azjl#3]

(The E myth. The side wall is not a stiff spring.​

I run my 37's at 35 PSI, air has more to do with it. Off road 15 front, 10 in rear (until my bead locks go on), very smooth ride. Getting 33x12.5R17 E rated K02's for the TJR.​

​

Spoken like a true mall crawler. E's are far superior off road, you won't blow the sidewall so easily. In my KoH crazy days, I blew 5 C rated tires in sharp rocks going thru the tread (at stupid speeds). Switched to E and the problem went away.)​

We might be talking around the same thing but here ya go:

Fact: E rated sidewalls are stiffer, to carry more load, period. I don't know who calls it a stiff spring, but by design, the wall is thicker, more layers, so it is stiffer.

Fact: E rated tires weigh a heck of a lot more, more rotational mass, worse gas mileage, worse stopping capability.

Fact: E rated tires are known to result in a stiffer ride, period. Now, this really happens because we do not load our E rated up like an F350 does. So in one respect you are correct, but you need to be at the same percentage of rated load as say a C or D rated tire to give you the same ride feel. If not, like most jeeps, it will give a stiffer ride. There is also a relation of lift, shocks, suspension setup, but generally, a stock jeep with E rated will ride much stiffer even if aired down to a good ride patch on the tread.

Fact: an E rated tire is a better offroad and load carrying tire because of the extra material in the carcass.

I had E Toyos on my 2dr, unless I aired down around town to 22psi, it bucked and bounced all over the road. Crappy accel and stopping as well seeing as each weighed about 100lbs. I then had D rated and it was smooth as silk, and I didn't give up anything on sidewall protection, because of my jeep weight vs sidewall rating.


(Why the obsession with a few pounds. It's the mass of the entire vehicle that counts.)

Untrue, rotational mass is what eats up your torque on accel and takes you longer to stop, because you are not stopping just a vehicle, you are stopping a spinning mass. Mass squared is the math on why a heavier tires are not always a goods thing. So that little bit of weight as you call it, an extra 50lbs per tire, ends up being 2500lbs of mass squared times 4=10,000lbs, times the moment arm times.

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[aldo98229]

Not true. 37" KM3's and we love it. 3 NITTO 38x13.5R17's in the garage with raceline beadlocks, the 4th should be here soon. Stock gears.

I hit D7 frequently going 50 MPH. I've hit D8 on the rare occasion I've up to 60. Who cares if you lose 8th? All I care about is wheeling and the 2.0 turbo, automatic, 4:1 xfer case climbs vertical at 1,200 RPM in M1.

Was getting 24 MPG with stock tires, dropped to 22 with 37's. But this is a dedicated wheeler and I'm shocked and pleased it gets that good of milage when 12% of the miles are crawling in low range. I do make aggressive use of MSS (Manual stop start, when we inspect the line).

A 4x4 is not a race car, even the 392 is a total joke compared to an 8 second Plaid.

I'm optimized for crawling, not for hitting 8th gear or off the line performance on the street.



Avoid “E” rated like the plaque bless you like the log wagon type ride.

The E myth. The side wall is not a stiff spring.
I run my 37's at 35 PSI, air has more to do with it. Off road 15 front, 10 in rear (until my bead locks go on), very smooth ride. Getting 33x12.5R17 E rated K02's for the TJR.

Spoken like a true mall crawler. E's are far superior off road, you won't blow the sidewall so easily. In my KoH crazy days, I blew 5 C rated tires in sharp rocks going thru the tread (at stupid speeds). Switched to E and the problem went away.



Why the obsession with a few pounds. It's the mass of the entire vehicle that counts.

What a bunch of hogwash.

Okay. Where’s the hidden camera...? ?

 

[JLR_AEV]

Soon I will need to update my tires on my Rubicon, so my question....can I run a light weight BFG KO2'S in 37 with the 4.10 gears or will it really pull MPG and drive ability down to a "no fun" level. I had thought about 35's but know the BFG run small. Btw I have the 2.0t for the engine.

Thanks for sharing your knowledge and thoughts.

Ran the exact set up you are asking about; 37 inch BFG load C's with a 1.5 lift. They, in my opinion, didn't bog the ride down and I have the 3.6L too. With the torque the 2.0t has you will be more than fine it seems. My MPG did take a small hit but that was expected ?

 

[SmallCrawler]

Not sure this has been mentioned, but if money is a consideration...

You can mount a spare 315 on the tailgate without modification. It might rub a little if you have the oem steel rear bumper, but it clears if you have the plastic rear bumper.

I have the steel bumpers, and though the slight tailgate rub was not a big deal, I added a Smittybilt tire relocation bracket and it has worked well.

 

[Gmanjeeper]

I just put on 315s on my JLR 3.6L 8AT and I’m liking the wider stance and more ‘planted’ feel. I lost about 1 to 1.5mpg at Hwy speeds. I also find it drops to 7th gear a little more often. Probably why my mileage is a little lower.

Will be lifting it with the 1.5in Clayton lift. Hopefully that doesn’t further degrade much.

Have you done the Clayton 1.5” lift? If so, do you know how much actual lift occurred? How is it working with your 315 KO2s.

 

[Zandcwhite]

It is fairly hilly and often windy. We do like to travel in the Jeep to off-road destinations - Colorado, Utah, Wyoming, etc.... I would rather not regear....maybe I will stick with going to 35's and enjoy....I typically don't do anything more than a moderate off road trail.

We wheeled moab twice, telluride, the Rubicon trail, and roadtripped our 2019 JLUR all over the western states with 37's and the stock 4.10s. Power was never lacking even at 13k+ foot elevations. We went to 5.38's after going to 38's and in my opinion the jeep was worse than it was with 4.10s. Fuel economy was no better with the 5.38s and it was a half second slower 0-60mph. The 2.0t doesn't seem near as great dependent as the V6 judging by how our 2022 XR with the V6 drives on comparison.

 

[entropy]

I just put on 315s on my JLR 3.6L 8AT and I’m liking the wider stance and more ‘planted’ feel. I lost about 1 to 1.5mpg at Hwy speeds. I also find it drops to 7th gear a little more often. Probably why my mileage is a little lower.

Will be lifting it with the 1.5in Clayton lift. Hopefully that doesn’t further degrade much.

My jeeps MPG went to shit when I lifted it by about the same amount the clayton lift will give you.

 

[dragoneggs]

Have you done the Clayton 1.5” lift? If so, do you know how much actual lift occurred? How is it working with your 315 KO2s.

I’m tickled pink… whatever that means. The lift netted about 2in (as advertised by Clayton) and I haven’t seen any appreciable additional mpg loss after going to 315s. Got my RoadMaster Exact Center steering stabilizer dialed in and I absolutely love the ride.

I have to mention I added Artec aluminum belly skids at the same time as the lift so maybe that helped the aerodynamics?

Also will add that I went with Fox 2.0 shocks with the Clayton 1.5in Overland+ lift. Have to say it is the sweet spot for me handling on/off roading with my 2dr Rubi.

 

[Zandcwhite]

Spoken like a true mall crawler. E's are far superior off road, you won't blow the sidewall so easily. In my KoH crazy days, I blew 5 C rated tires in sharp rocks going thru the tread (at stupid speeds). Switched to E and the problem went​

Fact: an E rated tire is a better offroad and load carrying tire because of the extra material in the carcass.

Better offroad is use case dependent. E rated tires are more cut resistant for sure. Racing through jagged rocks I'd absolutely recommend an E rated tire. Rock crawling in the Sierra's and moab slickrock in my road trip capable Jeep without beadlocks? E rated tires are absolutely not better. I've found the more flexible sidewalls of a C or D rated tire will stay on the bead at lower psi than an E rated tire. Running an E rated tire at 15psi to keep it on the wheel vs running a C rated tire at 10psi will result in way more traction and a much softer ride for the C rated tire. Aren't those things clearly "better off road"? Dozens of Rubicon trips and several weeks wheeling in moab I'd argue cutting a sidewall in those Terrains is unlikely. Factor in the better mpg, ride, acceleration, etc on road and unless you are rock racing or rock bouncing there's no reason to run an E rated tire on a JL in my opinion.

 

[Gmanjeeper]

I’m tickled pink… whatever that means. The lift netted about 2in (as advertised by Clayton) and I haven’t seen any appreciable additional mpg loss after going to 315s. Got my RoadMaster Exact Center steering stabilizer dialed in and I absolutely love the ride.

I have to mention I added Artec aluminum belly skids at the same time as the lift so maybe that helped the aerodynamics?

Also will add that I went with Fox 2.0 shocks with the Clayton 1.5in Overland+ lift. Have to say it is the sweet spot for me handling on/off roading with my 2dr Rubi.

Thanks for the input. I am torn between making my JLR capable off road, certainly so that I do not beat it up, vs keeping it stock with ride and handling I know no like and being able to get into and out of it easily etc. I am not a hard core rock crawler and we only take it off road once or twice a year for a week or two. Plus, my wife and I are neither young nor tall. LOL! I put our JL up on 3” blocks and while I could get in ok (sort of) I basically had to hop out and my wife did not like it at all! If I lifted it I would probably have to do step sliders of some kind.
How is your new Clayton ride compared to factory?

 

[dragoneggs]

Thanks for the input. I am torn between making my JLR capable off road, certainly so that I do not beat it up, vs keeping it stock with ride and handling I know no like and being able to get into and out of it easily etc. I am not a hard core rock crawler and we only take it off road once or twice a year for a week or two. Plus, my wife and I are neither young nor tall. LOL! I put our JL up on 3” blocks and while I could get in ok (sort of) I basically had to hop out and my wife did not like it at all! If I lifted it I would probably have to do step sliders of some kind.
How is your new Clayton ride compared to factory?

Going back and reading my previous post, I should clarify. I lost about a 1.5mpg going to 315 for 285. Adding the lift and belly skids did not further reduce my mileage.

I’m old and 6’2”. Getting in is a little more of a challenge but I get some stretching in. My wife is 5’5” and she isn’t crazy about it but she doesn’t drive it. Only sometimes as a passenger. I’m considering some kind of rock rail that would give her a step.

The ride is firmer and at first I was a little concerned when hitting potholes and ruts at higher speeds. It does hop a bit. But now I like the firm feel and the wider stance due to 0 offset wheels.

 

[Discount Tire]

One thing to consider when going bigger. Availability. 285/70R-17, lots of stock in many brands. 315/70R-17 not many options and less in stock. When you go 37 plus almost all tires would be special order unless you frequent a specialty off road shop.

 

[STW]

…Plus, my wife and I are neither young nor tall. LOL! I put our JL up on 3” blocks and while I could get in ok (sort of) I basically had to hop out and my wife did not like it at all! If I lifted it I would probably have to do step sliders of some kind…

since a couple folks have said they’d want step sliders to help get in the Jeep after a lift, I’ll mention step sliders did not help at all for my 5’ tall daughter to get in, nor for my mother. That’s assuming we’re talking about fixed-height step slider. I had some good frame-mounted sliders designed as proper sliders that didn’t kill clearance, and it’s a long first step up to that slider step. About 22” or so on an un-lifted stock height Rubicon. That first step puts you almost at the level of the door sill, which is where your slider step needs to be if it’s not going to reduce your clearance in the rocks. Some stylish sliders have lowered steps, built-in but obviously those reduce clearance.

The solution for someone looking to make it easier for a smaller, or less strong less steady, person to climb up into your lifted Jeep is a lower step that reduces the height of that first step up.

One way to do that is a step that you can hang off your slider then remove and toss in the back till you need it again. Garvin makes one that was tempting me for a while, but I didn’t like the idea of having to put it in place each time someone gets in the passenger side, then removing it to toss in the back. Then helping them out too. That’ll work for special guest once in a while, but for routine use no way. Pople prefer independence and most don’t want a big production just to get in the Jeep.

The better way is to install a step that lowers into place and then retracts out of the way on its own.

Rockslide Engineering makes their powered step that a lot of people here swear by. My use didn’t call for that big a production and I didn’t want or need that long a step.

My favorite solution so far is the M.O.R.E. Hide-A-Step, and I found the best price with ExtremeTerrain.com. Spring-loaded so it tucks up automatically out of the way and doesn’t affect clearance. It can be removed quickly and without tools for trails that need your full absolute rocker clearance.

When you step on it your foot pushes it down into place so the first step height is about 14”. Then it pops back up on it’s own so it’s almost not visible. Makes it easy to step up into the Jeep for anyone who can make a 14” step. Some folks would still have trouble reaching up to the slider level with a toe to push it down in the first place, and then the Rockslide auto-step is better.


Manufacturer YouTube video shows it in action on a lifted JLU with big tires

https://www.extremeterrain.com/more-jeep-wrangler-hide-a-step-jlst18.html
https://www.extremeterrain.com/more-jeep-wrangler-hide-a-step-black-jlst18b.html

It’s not inexpensive for how small and neat it is. But it’s a quality product and I looked for a year for something better that accomplished the same thing. Easy install and works with or without the Rubicon Rock Rails, but it wouldn’t fit with a lot of other sliders.

 

[Gmanjeeper]

since a couple folks have said they’d want step sliders to help get in the Jeep after a lift, I’ll mention step sliders did not help at all for my 5’ tall daughter to get in, nor for my mother. That’s assuming we’re talking about fixed-height step slider. I had some good frame-mounted sliders designed as proper sliders that didn’t kill clearance, and it’s a long first step up to that slider step. About 22” or so on an un-lifted stock height Rubicon. That first step puts you almost at the level of the door sill, which is where your slider step needs to be if it’s not going to reduce your clearance in the rocks. Some stylish sliders have lowered steps, built-in but obviously those reduce clearance.

The solution for someone looking to make it easier for a smaller, or less strong less steady, person to climb up into your lifted Jeep is a lower step that reduces the height of that first step up.

One way to do that is a step that you can hang off your slider then remove and toss in the back till you need it again. Garvin makes one that was tempting me for a while, but I didn’t like the idea of having to put it in place each time someone gets in the passenger side, then removing it to toss in the back. Then helping them out too. That’ll work for special guest once in a while, but for routine use no way. Pople prefer independence and most don’t want a big production just to get in the Jeep.

The better way is to install a step that lowers into place and then retracts out of the way on its own.

Rockslide Engineering makes their powered step that a lot of people here swear by. My use didn’t call for that big a production and I didn’t want or need that long a step.

My favorite solution so far is the M.O.R.E. Hide-A-Step, and I found the best price with ExtremeTerrain.com. Spring-loaded so it tucks up automatically out of the way and doesn’t affect clearance. It can be removed quickly and without tools for trails that need your full absolute rocker clearance.

When you step on it your foot pushes it down into place so the first step height is about 14”. Then it pops back up on it’s own so it’s almost not visible. Makes it easy to step up into the Jeep for anyone who can make a 14” step. Some folks would still have trouble reaching up to the slider level with a toe to push it down in the first place, and then the Rockslide auto-step is better.


Manufacturer YouTube video shows it in action on a lifted JLU with big tires

https://www.extremeterrain.com/more-jeep-wrangler-hide-a-step-jlst18.html
https://www.extremeterrain.com/more-jeep-wrangler-hide-a-step-black-jlst18b.html

It’s not inexpensive for how small and neat it is. But it’s a quality product and I looked for a year for something better that accomplished the same thing. Easy install and works with or without the Rubicon Rock Rails, but it wouldn’t fit with a lot of other sliders.

Thanks. I had a lifted JTR with 37s and had the RSE power steps. My 5’2” wife really did not like them, she said they were not stable and “wiggled” too much. I thought they were pretty good, but not great for getting in the back seats. Plus, they are expensive! I showed my wife the MORE step and she was not thrilled saying it is small and looks hard to get to especially when getting out. Everything is a compromise. IF I put on a lift, maybe I I’ll just carry a small stool like conductors did for passengers getting into railroad cars!!! Since I am not going to do any hard core off roading etc, I probably should see how my JLR performs without a lift and bigger tires. As one forum member pointed out on another thread, 33s used to be the off roading standard.

 

[Gmanjeeper]

Going back and reading my previous post, I should clarify. I lost about a 1.5mpg going to 315 for 285. Adding the lift and belly skids did not further reduce my mileage.

I’m old and 6’2”. Getting in is a little more of a challenge but I get some stretching in. My wife is 5’5” and she isn’t crazy about it but she doesn’t drive it. Only sometimes as a passenger. I’m considering some kind of rock rail that would give her a step.

The ride is firmer and at first I was a little concerned when hitting potholes and ruts at higher speeds. It does hop a bit. But now I like the firm feel and the wider stance due to 0 offset wheels.

So, everything is a bit of a compromise. I had a lifted JTR with 37s and the RSE power steps. For various reasons, my wife did not like the steps. In fact, while she thought the JTR was ultra sharp looking, she did not like riding in it and we ending up selling it and getting the JLR. We both like it a lot - it is kind of a Jeep sports car. Since I am not a hard core off roader, either in terms of difficult trails, or doing trails frequently, I probably should try it stock and see how it performs on the trails we do etc. Thanks again for your input. ( By the way, I have a friend with a JKR with a two inch lift and 34s. Based upon measurements he HS taken of his JK, I think my stock JLR has about the same ground clearance as his Jeep.

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