2021 eco diesel gas mileage

[NWRogue]

If (and that's a big one) I can keep mine at 65-68mph I see 30+ mpg, driving how I normally do 70-80mph I see between 25 and 26mpg. 3.92 4x4 Limited with stock Bridgestone 20's. Current trip (still need to get home) mileage is 1650+ miles and mileage on the computer is 25.6mpg, 98% freeway (see the above 70-80mph), some rather long steep hills on that drive.

 

[KNGSNK11]

I wonder how tires play into mpg, currently have the stock size wildpeaks on mine and tomorrow plan on putting on some firestone destination's XT in 275 65 20, slightly bigger and I think only weight 10 lbs more than the stock tires.
When I was working down in central Florida, I was getting 24-25 going to work in the mornings, but its mostly flat down there. Here in central Missouri driving around rural highway etc, it usually gets 22mpg and that's with 40 psi in the tires.

 

[KNGSNK11]

Falken Wildpeaks that come standard on the 4x4 North package, 33gal tank

Not sure where you are from, but is it mostly flat lands there?

Here in Missouri it pretty hilly so I usually get 22 maybe 23 mpg on a good day.

 

[KNGSNK11]

With 3.21 axle and stock tires it's very possible. But with 3.92 axle it becomes much much harder to see those numbers, and aftermarket tires pretty much make it impossible.

The best I EVER saw was 29 MPG on a 170ish mile trip at 55 MPH. Once you start to exceed 55 the MPG starts going down rapidly. I will never believe that guys are seeing 30 MPG in a North Edition 4x4 with 3.92 gears out on the interstate at 70+ MPH. Ain't happening.

What I don't understand, is it seems a lot of guys that are getting 28+ have 33 gal fuel tanks and are in higher trim levels than my ORP bighorn and by all rights be heavier than me but yet get better fuel mileage, there has to be different tuning from the factory or something.

 

[J-Cooz]

I wonder how tires play into mpg, currently have the stock size wildpeaks on mine and tomorrow plan on putting on some firestone destination's XT in 275 65 20, slightly bigger and I think only weight 10 lbs more than the stock tires.
When I was working down in central Florida, I was getting 24-25 going to work in the mornings, but its mostly flat down there. Here in central Missouri driving around rural highway etc, it usually gets 22mpg and that's with 40 psi in the tires.

10lbs per tire is significant extra unsprung weight. I think it's a rule of thumb that every 1lb of unsprung weight is like adding 4lbs of regular weight to the car.

So you'd be theoretically adding 160lbs.

 

[c3k]

I get great highway mileage (see sig), but it starts to drop once I go much above 72mph or so. 30+ on long trips.

If I don't hyper-mile, I'll be in the upper 20s (28 or so), and that includes mid to upper 70s with the occasional 80mph.
I did air-up my tires a bit. I've got about 4,000 miles on my engine.

Maybe I got a good lottery pick?

 

[Bad Notch]

With 3.21 axle and stock tires it's very possible. But with 3.92 axle it becomes much much harder to see those numbers, and aftermarket tires pretty much make it impossible.

The best I EVER saw was 29 MPG on a 170ish mile trip at 55 MPH. Once you start to exceed 55 the MPG starts going down rapidly. I will never believe that guys are seeing 30 MPG in a North Edition 4x4 with 3.92 gears out on the interstate at 70+ MPH. Ain't happening.

I get my best mpg at 72 mph with adaptive cruise on...

2021 limited with 3:21 / hwy tires / 4x4 / 33gal

 

[Bad Notch]

I get great highway mileage (see sig), but it starts to drop once I go much above 72mph or so. 30+ on long trips.

If I don't hyper-mile, I'll be in the upper 20s (28 or so), and that includes mid to upper 70s with the occasional 80mph.
I did air-up my tires a bit. I've got about 4,000 miles on my engine.

Maybe I got a good lottery pick?

My 21 limited is very consistent with yours. I have actually seen 37 mpg on a 45 mile hwy loop ( hyper miling my *** off ) LOL

 

[c3k]

My 21 limited is very consistent with yours. I have actually seen 37 mpg on a 45 mile hwy loop ( hyper miling my *** off )

Yeah, if I keep it in 8th (by monitoring gear selection on display and modifying throttle) and low speeds (45 to 50) my mileage is insane.

Oh...when I recently towed my little utility trailer (6x12, single axle, 4' gate) weighing about 2,000 pounds? The baby diesel didn't even feel the extra weight or drag. Yes, my mileage dropped at highway speeds, but rpm and gear selection and response were as if there was nothing behind me.

I am more and more impressed with this truck the more I drive it.

 

[mrfreon]

Not sure where you are from, but is it mostly flat lands there?

Here in Missouri it pretty hilly so I usually get 22 maybe 23 mpg on a good day.

Nearly flat here on the Ohio & Indiana border. That drive was taken on July 4th with speeds in the lower 60s MPH and warm temps which seem to increase MPG.

 

[KNGSNK11]

Nearly flat here on the Ohio & Indiana border. That drive was taken on July 4th with speeds in the lower 60s MPH and warm temps which seem to increase MPG.

I had to take my truck in today to get the pinion seal replaced, there and back is roughly 170 miles, keeping my speeds on the rural hwys at 55 mph the best I could and then 65 mph on Hwy 65 going south/north to/from Springfield Mo, the best I seen on the lie o meter was 23.4 mpg but that's with the firestone destination's XT 275 65 20 on now.

What I want to know is how Ram calculated the fuel mileage on the window sticker, my sticker says 21 city 29 hwy 24 combined. Do they test these trucks a 55 mph to get these numbers or what?, because if that's the case, I hardly run at 55 I'm usually running at 70+ on the interstates.

 

[Howie Dub]

I had to take my truck in today to get the pinion seal replaced, there and back is roughly 170 miles, keeping my speeds on the rural hwys at 55 mph the best I could and then 65 mph on Hwy 65 going south/north to/from Springfield Mo, the best I seen on the lie o meter was 23.4 mpg but that's with the firestone destination's XT 275 65 20 on now.

What I want to know is how Ram calculated the fuel mileage on the window sticker, my sticker says 21 city 29 hwy 24 combined. Do they test these trucks a 55 mph to get these numbers or what?, because if that's the case, I hardly run at 55 I'm usually running at 70+ on the interstates.

I believe it is based on driving 55 on the freeway. When I first got my truck, I stayed below 60 so I could get my system monitors ready for Commifornia's smog test. I drove about 100 miles with no traffic and the truck gauge showed I averaged 28.5 MPG with only myself in the truck. I'm on stock Goodyear Eagles. I just drove 120 miles and averaged 25.3 MPG with 5 people and a packed bed going between 70-80 MPH with some stop and go traffic mixed in. I read AT tires can affect fuel economy by 1-3 MPGs.

 

[c3k]

The numbers come from running a specific government-mandated test. I don't recall the test regime offhand, or how they weight highway vs. city to come up with combined. But they specify fuel load, speeds, accelerations, etc. It's run on a dynometer.

The actual numbers may or may not have any correlation to how the vehicles perform on roads. They DO correlate so that each brand is comparing apples to apples. So, if Car A says "88 mpg" and Car B says "44 mpg", you can be reasonably sure that you'd see about double the mileage in A than in B should you buy one. Doesn't mean you'd see 88 (or 44).

All the above from a distant memory.

ETA a linkee: https://fueleconomy.gov/feg/how_tested.shtml

Vehicle and Fuel Emissions Testing | US EPA

EPA's National Vehicle and Fuel Emissions Laboratory's primary responsibilities include: evaluating emission control technology; testing vehicles, engines and fuels; and determining compliance with federal emissions and fuel economy standards.

www.epa.gov

 

[KNGSNK11]

I believe it is based on driving 55 on the freeway. When I first got my truck, I stayed below 60 so I could get my system monitors ready for Commifornia's smog test. I drove about 100 miles with no traffic and the truck gauge showed I averaged 28.5 MPG with only myself in the truck. I'm on stock Goodyear Eagles. I just drove 120 miles and averaged 25.3 MPG with 5 people and a packed bed going between 70-80 MPH with some stop and go traffic mixed in. I read AT tires can affect fuel economy by 1-3 MPGs.

I take it your Goodyear eagles are not A/T tires?

 

[Howie Dub]

I take it your Goodyear eagles are not A/T tires?

Not AT, just the all season touring ones that came with the truck.

 

[Dragonmaster13]

Did a 6+hr highway trip yesterday and my gauge was reading over 30mpg in my Rebel for most of it. Hand calc on filling was 29.4mpg, 7.995L/100km. Trip had a few 12% hills for 15km, uphill on the way there, downhill on the way back, no wind and 26C out. Speed between 100 and 120km/h (60 and 75mph). Truck was more efficient in eighth at 120/75 than it was at 110/68.

 

[traveller09]

Did a 6+hr highway trip yesterday and my gauge was reading over 30mpg in my Rebel for most of it. Hand calc on filling was 29.4mpg, 7.995L/100km. Trip had a few 12% hills for 15km, uphill on the way there, downhill on the way back, no wind and 26C out. Speed between 100 and 120km/h (60 and 75mph). Truck was more efficient in eighth at 120/75 than it was at 110/68.

Wow, that is impressive for a Rebel. Mine is new with less than 250 miles on the clock and the dash gauge hasn't broken 20 MPG yet. This weekend we are heading on a road trip to California, I would love to see high 20's but we will see. I will report back on our return.

 

[jgibbs913]

I recently bought the 2020 Eco Diesel with around 7600 miles. I then drove the truck from South Florida to Sevierville Tennessee. I averaged 29.4 mpg on my way there. On the way back I averaged 32.5. The next trip I took was 182 miles back roads and some highway plus through Orlando and had an average of 36.5 mpg. I switched from a 2016 Ram 1500 Hemi and man this mpg has impressed me so far.

 

[Dragonmaster13]

Wow, that is impressive for a Rebel. Mine is new with less than 250 miles on the clock and the dash gauge hasn't broken 20 MPG yet. This weekend we are heading on a road trip to California, I would love to see high 20's but we will see. I will report back on our return.

That’s where I was for the first few tanks, third it went up dramatically.


2012 4th gen SXT crew Hemi retired.
Factory ordered 2021 Rebel Billet Silver Metallic EcoDiesel March 10, built May 18, build sheet May 19, window sticker May 22, delivered June 9. Dutchmen 268bhs 33’ trailer, 7600lbs +/- 100lbs loaded and scaled.

 

[DaveLink]

Just got back from a long trip, with 3 adults and 2 kids and a very packed truck bed plus platform with additional weight on a fishing trip from Kentucky to Wisconsin, and per the computer:
1864.4 miles, 24.1 mpg, 30:14:43 time.

When possible, I was doing 85 mph on the highway. Limited in town driving on this trip, but several interstate back ups. Headwind both ways it seemed. I'm not patient on the highway. 10 mph faster over 12 hours is worth it.