Rubicon Diesel MPG.... at what speed?

[AEsco48]

How does the MPG of the Diesel Rubicon vary with speed?

Like what MPG would a Rubicon Diesel get cruising on the highway at 90mph?

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[AEsco48]

Or am I crazy to think the Rubicon can go 90 mph

 

[TheSolarWizard]

No vehicle has anywhere near peak efficiency at 90 mph.
my model Y range starts plummeting at 82 mph
people think the downward spiral in a Jeep starts about 62mph due to the(lack of) aerodynamics

on a sport with stock tires I’d be surprised if you could break 20mpg at 90 on dead flat road and no wind. Realistically on a stock sport I think you could count on 17-18mpg


this does nothing to speak of the lack of stability or safety at that speed in a Jeep.

 

[Daniel Snider]

my first full tank and not gunning it at all got me 25.3 on the screen, but when I did the math myself with a calculator, it was 23.3.... exactly 400 miles on the tank

 

[Mr._Bill]

With my Nissan Leaf, the most efficient speed is supposed to be 38mph, and it is a very aerodynamic vehicle. With the Jeep, I would say it is right at the point where it drops into eighth gear, somewhere around 45 to 55mph.

 

[Schreconjeep]

I have 37s but there is a sharp decrease in MPG above 60mph. At 75mph you are using a significant amount of fuel even going down hill. Pretty sure over 55, most of your power is used to overcome aerodynamics. Through the mountains of Western Maryland and WV I got 22+mpg going ~63mph average in the pouring rain and return trip was 20mpg at ~72mph on dry pavement. I also wouldn't be driving over 75 regularly with 37s and my kids in the truck.

 

[Chris Mac]

I am averaging around 23 mpg at 80 on relatively flat ground on my commute.

 

[JT18]

I got 27mpg when cruising on the backroads and keeping it at 60mph.

JT18

 

[briandmiles]

Just drove my new JTR Ecodiesel home from Petersons in Boise. 330 miles, it took more than a tank of fuel to get home and the gauge was reading about 17mpg average for the first tank. Running close to 80mph with a 4 inch lift and 37's. Second tank was closer to 20mpg but I was definitly driving more slowly, 72-78 mph and only for the last 70 miles or so.

Brian

 

[Stevevdbh]

Just drove my new JTR Ecodiesel home from Petersons in Boise. 330 miles, it took more than a tank of fuel to get home and the gauge was reading about 17mpg average for the first tank. Running close to 80mph with a 4 inch lift and 37's. Second tank was closer to 20mpg but I was definitly driving more slowly, 72-78 mph and only for the last 70 miles or so.

Brian

Did peterson add your lift and tires etc? Do you recommend them for aftermarket parts install? Which lift did you go with?

 

[CaptNkllm]

Picked up mine and drove from Anaheim to Las Vegas @ 80mph and was over 21 mpg.. Some big hills and some flat spots.. Jeep had 20 miles on it when I picked it up.

 

[briandmiles]

Did peterson add your lift and tires etc? Do you recommend them for aftermarket parts install? Which lift did you go with?

Yes, they did the work so I could just pick it up and go. They did really good work and talking to all the people involved it seems like they do a lot of suspension modifications. I went with the EVO JT Pro kit. Coilovers on all 4 corners drives like a dream. I asked for about a 4 inch lift and they got the wheels I wanted and the tires as well. Probably could have got it done a little cheaper but getting it all done in one spot was much easier.

Brian

 

[smlobx]

A diesel will take several thousand miles to break in...maybe as much as 10K and a couple of oil changes so you mileage should constantly improve relative to your situation.

 

[BEERviper]

I have 37s but there is a sharp decrease in MPG above 60mph. At 75mph you are using a significant amount of fuel even going down hill. Pretty sure over 55, most of your power is used to overcome aerodynamics. Through the mountains of Western Maryland and WV I got 22+mpg going ~63mph average in the pouring rain and return trip was 20mpg at ~72mph on dry pavement. I also wouldn't be driving over 75 regularly with 37s and my kids in the truck.

Wow I would say this is very respectable MPG considering a Rubicon with 37's!
This is helping me make the decision to go 37's when I get my JT Sport S diesel as I've been on the fence.

I have a 2016 JKU now with 35's and my average over 50k miles is 15.7 MPG! To see numbers in the 20's before the engine is even broken in is incredible!

I may still end up regearing to make towing more manageable but won't make that decision until after I pull the camper once or twice.

Maybe even do my own "IKE Gauntlet" pulling my camper since I live in Colorado when the roads are dry.

 

[WMWHV]

I had been averaging 24 and change driving in town with 1000 miles, which means a lot of freeway time at 60-65 and some surface streets. I took my first road trip and was going around 75 or so on the interstate for 250 miles each way. Gas mileage dropped to around 22 on that trip. Once you cross 70, the mileage seems to suffer. Not complaining, just reporting. At 75 in my LJ, it would have been roaring like a beast and getting less than 10. In the JT, I can have a quiet conversation with my wife at 85 and still have plenty of pedal in reserve. What a change.

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