2dr Rubicon tire question

[dchemphill1]

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.

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[Philly_]

How are the hills and wind where you’re at?

If it’s super flat and wind is mild, many have said 37’s on the rubicon 4.10’s is all they will ever need. In my opinion, you might find the power lacking if you have to deal with heavy winds all the time. I have BFG KO2’s in 315/70/17 (35’s) and the stock gearing and I have 0 complaints no matter the terrain or weather up to about 55mph. After that, any bit of wind or hills starts to impact power and mileage to where it is noticeable. A lot of that does come from the lift, though.

It’s not enough to warrant a regear, in my opinion, but if/when I go to 37’s, I plan to regear to compensate. Either 4.88’s or 5.13’s depending on how heavy my Jeep is when I get there and if decide I will go to 38x12.50 someday. I am also looking at KO2’s as the 37’s I would swap on.

If a regear isn’t in the budget at the moment, it’s definitely drivable without and you can save until it makes sense.

 

[dchemphill1]

How are the hills and wind where you’re at?

If it’s super flat and wind is mild, many have said 37’s on the rubicon 4.10’s is all they will ever need. In my opinion, you might find the power lacking if you have to deal with heavy winds all the time. I have BFG KO2’s in 315/70/17 (35’s) and the stock gearing and I have 0 complaints no matter the terrain or weather up to about 55mph. After that, any bit of wind or hills starts to impact power and mileage to where it is noticeable. A lot of that does come from the lift, though.

It’s not enough to warrant a regear, in my opinion, but if/when I go to 37’s, I plan to regear to compensate. Either 4.88’s or 5.13’s depending on how heavy my Jeep is when I get there and if decide I will go to 38x12.50 someday. I am also looking at KO2’s as the 37’s I would swap on.

If a regear isn’t in the budget at the moment, it’s definitely drivable without and you can save until it makes sense.

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.

 

[Reinen]

As the guy who doesn't get large tires just to have large tires...
If you're going to limit yourself to moderate trails anyway (no judgement, I do the same) then you'll find 35s are enough. It's a better balance between off road ability and power/range without going down the regear rabbit hole.

 

[aldo98229]

A Jeep with 4.10 gears is going to be a dog on 37s. Period.

Yup. You read it here first.

 

[dragoneggs]

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.

 

[aldo98229]

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.

Famous last words!

 

[Shibadog]

Question: Have you been unhappy with your Jeep’s performance on the stocker’s? You are driving one of the most capable vehicles out there. Unless you have had issues on the trails YOU run my opinion is to stay stock size. Is the “look” worth a decrease in performance and mpg’s? Your call, but think about it. If you’ve “Gotta Have” bigger tires then go with the 315’s and “C” rated. Heavier tires will adversely affect ride and performance, and Very heavy tires with stiff sidewalls aren’t much fun on a DD. Avoid “E” rated like the plaque bless you like the log wagon type ride. My “S” with LSD and 285’s has been an incredibly competent rig for the off roading I do. 315’s should clear ok on your Rubicon. 37’s may also rub, esp on a trail.

 

[76_iron]

Mine is good enough that I am not going to regear any time soon. Get 18-20 mpg, 0-60 is right around 7 seconds. I also got lightweight wheels, might be a different story with heavy beadlocks.

 

[OhioJeeper]

Yours is a short 2 door w/good ground clearance, I'd stick w/35's. You'll clear a lot of trail obstacles without affecting highway mileage too terribly. Other issue is poor mpg with 37's, the required lift and that small fuel tank. You'll be stopping for fuel all too often. That blows if you travel a lot, which it sounds like you will.

 

[dragoneggs]

Question: Have you been unhappy with your Jeep’s performance on the stocker’s? You are driving one of the most capable vehicles out there. Unless you have had issues on the trails YOU run my opinion is to stay stock size. Is the “look” worth a decrease in performance and mpg’s? Your call, but think about it. If you’ve “Gotta Have” bigger tires then go with the 315’s and “C” rated. Heavier tires will adversely affect ride and performance, and Very heavy tires with stiff sidewalls aren’t much fun on a DD. Avoid “E” rated like the plaque bless you like the log wagon type ride. My “S” with LSD and 285’s has been an incredibly competent rig for the off roading I do. 315’s should clear ok on your Rubicon. 37’s may also rub, esp on a trail.

Don't know the OP's situation but in my case, Yes... I ran a BOH trail in Oregon with my stock Rubicon and scraped the bottom multiple times on rocks. I told myself prior I would keep it stock. Now I feel I 'need' next size bigger tires and small lift. Hoping this is the happy sweet spot.

Oh, and looking at belly skids now as well. The Rubicon trail is on my To Do list.

 

[SmallCrawler]

Here's another vote for the relatively lightweight, C-rated BFG K02 315s. They've been great on my (essentially) stock 2.0t JLR... comfortable on the highway and capable on a variety of trails. Next step for me will be a small lift so I can handle the tougher obstacles and ledges that often appear/develop on the "easy" trails.

 

[Headbarcode]

A Jeep with 4.10 gears is going to be a dog on 37s. Period.

Yup. You read it here first.

Have you ever driven a JL Rubicon with the 2.0 turbo engine and 37's or larger?

I drove my 2.0 JLUR for over 50k miles on 38x13.5's, and it was far from a dog. It didn't start growing a tail until I swapped to 40x13.5's.

Plus, the OP has the added advantage of a lighter 2 door, on top of the torque advantage of the 2.0 engine.

 

[J0E]

A Jeep with 4.10 gears is going to be a dog on 37s. Period.

Yup. You read it here first.

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.

Question: Have you been unhappy with your Jeep’s performance on the stocker’s? You are driving one of the most capable vehicles out there. Unless you have had issues on the trails YOU run my opinion is to stay stock size. Is the “look” worth a decrease in performance and mpg’s? Your call, but think about it. If you’ve “Gotta Have” bigger tires then go with the 315’s and “C” rated. Heavier tires will adversely affect ride and performance, and Very heavy tires with stiff sidewalls aren’t much fun on a DD. Avoid “E” rated like the plaque bless you like the log wagon type ride. My “S” with LSD and 285’s has been an incredibly competent rig for the off roading I do. 315’s should clear ok on your Rubicon. 37’s may also rub, esp on a trail.

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.

Here's another vote for the relatively lightweight, C-rated BFG K02 315s. They've been great on my (essentially) stock 2.0t JLR... comfortable on the highway and capable on a variety of trails. Next step for me will be a small lift so I can handle the tougher obstacles and ledges that often appear/develop on the "easy" trails.

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

 

[J0E]

Don't know the OP's situation but in my case, Yes... I ran a BOH trail in Oregon with my stock Rubicon and scraped the bottom multiple times on rocks. I told myself prior I would keep it stock. Now I feel I 'need' next size bigger tires and small lift. Hoping this is the happy sweet spot.

Oh, and looking at belly skids now as well. The Rubicon trail is on my To Do list.

With a 2.5" lift you can run 37's. I'll be running 38's with my 2.5 lift but I had to get inner liners and a stubby front bumper. 37 is the known safe limit, why not go with that? Haven't done the Rubicon yet but I'm told a JLR on 37's is really fun.

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