I’m truly perplexed - NOT trolling!

[Roky]

Hey Roky, good to hear from you! When are we going wheeling again? Keep an eye on Ian, brother. Let me know if you need anything.

Yeah thanks brother, we’re keeping an eye on it. It shifted a little to the west, so hoping wiggles a little more to the west would be better. But we got fuel for the gen and plywood for the windows, you know the drill….. we’ve been out in the woods a couple times, in the last few weeks, work has been crazy busy for both of us…..anytime y’all wanna go just holler, easy for us we live across the street…..

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[Montanabound]

I have 3.6, 315/70/17s,heavy wheels, and the top is always down. I still hold 8th at 70mph.

I only read the first post so if you proved the myth wrong idc. Behold my jeep

 

[CarbonSteel]

@Wabujitsu - forgot one in my list of things that impact performance:

Weight.

My JLUR weighs 5970...

 

[CarbonSteel]

I have 3.6, 315/70/17s,heavy wheels, and the top is always down. I still hold 8th at 70mph.

I only read the first post so if you proved the myth wrong idc. Behold my jeep

2 doors are less impacted (as expected)...

 

[NewJLU2019]

Yeah thanks brother, we’re keeping an eye on it. It shifted a little to the west, so hoping wiggles a little more to the west would be better. But we got fuel for the gen and plywood for the windows, you know the drill….. we’ve been out in the woods a couple times, in the last few weeks, work has been crazy busy for both of us…..anytime y’all wanna go just holler, easy for us we live across the street…..

LIVE ACROSS STREET!!!

 

[SilentBanshee424]

I’ve been up to 75MPH, same result, but I do live in FL.

I live in FL too. Stock gearing (3.45) on a 6MT Sport S 2dr. The 3.6 definitely doesn't have the low down torque of the 2.0 so that's probably how you're getting into 8th so easily. We Floridians are a bit of an outlier in the Jeep community cuz we don't have nearly as many hills or crosswinds. Now once I went west to Arkansas I had to cruise in 5th at 75mph cuz the hills/mountains of the Ozarks were so intense.

 

[SLORubi]

I’m in MI, not major hills but enough that I’m dropping to 7th all the time. JLUR with the 3.6 on 35s, I get about 15 mpg, I may be a bit heavy footed on take off. I’ve thought about going 4.88 gears, but while I think I’ll get 8th back more, I’m not really going to gain much in mpg will I?

 

[txj2go]

Flat and at sea level which equates to low resistance and maximum HP/TQ.

And also a Rubi on larger tires is still geared better than a stock Sport on its 31.5" tires.

 

[azwjowner]

Don't forget with larger tires without regearing, you permanently increase the stresses on the transmission. 37/33 = 12% additional torque on the transmission all the time. How bad that is, I don't know.

 

[CarbonSteel]

I’m in MI, not major hills but enough that I’m dropping to 7th all the time. JLUR with the 3.6 on 35s, I get about 15 mpg, I may be a bit heavy footed on take off. I’ve thought about going 4.88 gears, but while I think I’ll get 8th back more, I’m not really going to gain much in mpg will I?

You will restore MPG to close to what you had simply because you are not lugging the engine at certain times or running very high rev's at others.

At speeds between 65 and 70 I get 17-19, more at lower speeds, but a lot less as I approach 75 and 80 (typically 15-16).

You will also put less strain on the drivetrain and will have a much better driving experience.

I have 37's and 5.13s now, but have gone through the full gambit:

33's + 4.10s
35's + 4.10s
35's + 4.88's
37's + 4.88's
37's + 5.13's

 

[SLORubi]

You will restore MPG to close to what you had simply because you are not lugging the engine at certain times or running very high rev's at others.

At speeds between 65 and 70 I get 17-19, more at lower speeds, but a lot less as I approach 75 and 80 (typically 15-16).

You will also put less strain on the drivetrain and will have a much better driving experience.

I have 37's and 5.13s now, but have gone through the full gambit:

33's + 4.10s
35's + 4.10s
35's + 4.88's
37's + 4.88's
37's + 5.13's

Thanks!

 

[jaardappel]

Roger that LOL! I’ve never had a complaint. On my previous Sport JLU I mounted 35 MTs with the crappy 3.45 gearing and held 8th up to 90 MPH on the flats. It too was a 2.0T.

I put 35’s (KO2’s) on mine and the MOPAR 2” as well….recalibrated the tire size with my Tazer Mini and….now I get better gas mileage on the freeway. 2.0 as well. Still super zippy and burns it well with traction control off (I don’t do that a lot). Odd. But hey, good on you. Pleasant surprise right?

 

[Wabujitsu]

I put 35’s (KO2’s) on mine and the MOPAR 2” as well….recalibrated the tire size with my Tazer Mini and….now I get better gas mileage on the freeway. 2.0 as well. Still super zippy and burns it well with traction control off (I don’t do that a lot). Odd. But hey, good on you. Pleasant surprise right?

Indeed a pleasant surprise! I have a JKS 2.5” lift, and I lost 1MPH from 20 down to 19. Most of my driving is country roads with a bit of city, with a few miles on interstate now and then. I also go a bit easy on the skinny pedal - sometimes

 

[roaniecowpony]

I put 35’s (KO2’s) on mine and the MOPAR 2” as well….recalibrated the tire size with my Tazer Mini and….now I get better gas mileage on the freeway. 2.0 as well. Still super zippy and burns it well with traction control off (I don’t do that a lot). Odd. But hey, good on you. Pleasant surprise right?

There is a sweet spot for every condition. If you noticed the trend (in all cars in general) in transmissions and gearing over the past 50-60 years, it has been to taller overall drive ratios (lower engine rpm). First it was done by simply by changing axle ratios, to the point where some cars had ratios near 2.00:1, while still using those old 2, 3, and 4 speed transmissions.

What the makers were chasing is a condition in the engine where it isn't turning too fast (or too slow) but making higher cylinder pressures when combustion occurs. The fuel burns more completely at those higher pressures and converts a higher percentage of fuel to power. In WW2, Charles Lindberg was sent to the south Pacific as an observer. After flying some missions, he famously showed P-38 pilots how to reduce rpm and increase manifold pressure (throttle) to get enough better fuel economy to fly extended missions.

The problem with cars going to taller gears became acceleration. With the old 2, 3, 4, speed transmissions, the performance and fuel economy suffered in the acceleration phase. That's when the transmission wars began. The "lock-up" torque converters came in and boosted the auto trans to near manual transmission efficiency. When the computer controlled multi speed auto transmissions started appearing, they started beating fuel economy (and acceleration) of many manual transmissions. We're up to having 8 and 10 speed transmissions in everyday vehicles, all in the pursuit of fuel economy.

 

[aldo98229]

My Sahara V6 with a Mopar lift and 35s would never shift past 6th speed on the stock 3.45 gears. Last winter I re-geared to 4.88: the Jeep now not only shifts all the way up to 8th speed, but it also automatically holds the gears on descents, and it takes off from a standing still with gusto.

A buddy, here in mountainous Washington too, got a 2022 Rubicon 2-door with the V6 eTorque a couple months ago. He also got a Mopar lift, and 315 Duratracs. He hasn’t had to regear: it appears the combination of 4.10 gearing and the eTorque are sufficient to keep his JL running just fine.

Also, because eTorque kicks in right when the tires start moving, which is the moment when larger tires take the greatest toll on the engine, he has seen the 35s have very little impact on his fuel consumption.

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