Fuel Economy 3.21 vs 3.92

[dave-o]

Hi all,
About to buy a 2019 or 2020 1500.
There are some amazing deals on 2019's out there (saw one high-end nearly 30% of MSRP the other day). I know the year of depreciation and other issues factor in, but I would consider a 2019 if I can find the right one (scouring the country without luck yet). But if I compromise, I have seen the truck I want with 3.92 rear axle ratio. I will at most pull a jet ski or lawn tractor. I don't need this feature.

My question is - how much of a fuel economy hit will I take? The stickers print the same, but I wonder if that is true in practice.

Thanks all!
Dave

 

[2wd]

Here is a recent thread on the topic if you want to read more.

Difference in gas mileage between the 3.21 and 3.92?

Majority of trucks come with the 3.92 gear ratio. The ones with 3.21 aren't the ones I prefer due to color, model, options, etc.... No plans to haul/tow so trying to stick with the 3.21, but curious to know the gas mileage difference people are seeing between the 3.21 and 3.92 for daily use...

5thgenrams.com

The 3.21 really only provides a benefit on the highway. If you do a lot of highway driving, you will likely notice the MPG difference as the 3.21 in 8th gear will be running lower RPM's than the 3.92 in 8th. In the numerous MPG threads I've visited, I've seen 3.21 guys reporting 25 MPG highway in the right conditions. The best I've seen from a 3.92 is 21 MPG. I've gotten 24 mpg twice on 2 separate interstate trips of 500+ miles with 3.21.

That being said if the deal is amazing on the 2019 with 3.92 I'd jump on it. Over the life of the truck you're only going to save maybe 1-2 thousand dollars from the highway MPG difference (maybe 3-4k if you keep it through 200k miles).

 

[Trooper4]

Here is a recent thread on the topic if you want to read more.

Difference in gas mileage between the 3.21 and 3.92?

Majority of trucks come with the 3.92 gear ratio. The ones with 3.21 aren't the ones I prefer due to color, model, options, etc.... No plans to haul/tow so trying to stick with the 3.21, but curious to know the gas mileage difference people are seeing between the 3.21 and 3.92 for daily use...

5thgenrams.com

The 3.21 really only provides a benefit on the highway. If you do a lot of highway driving, you will likely notice the MPG difference as the 3.21 in 8th gear will be running lower RPM's than the 3.92 in 8th. In the numerous MPG threads I've visited, I've seen 3.21 guys reporting 25 MPG highway in the right conditions. The best I've seen from a 3.92 is 21 MPG. I've gotten 24 mpg twice on 2 separate interstate trips of 500+ miles with 3.21.

That being said if the deal is amazing on the 2019 with 3.92 I'd jump on it. Over the life of the truck you're only going to save maybe 1-2 thousand dollars from the highway MPG difference (maybe 3-4k if you keep it through 200k miles).

I usually get about 20-21 on the highway, but have gotten 23 on two separate long trips when I just took it easy and stayed at 60-65 freeway and two lane highway driving. Outside temps were in the low 70's, and no wind.
5.7 e-torque and 3.92's

 

[redriderbob]

Hi all,
About to buy a 2019 or 2020 1500.
There are some amazing deals on 2019's out there (saw one high-end nearly 30% of MSRP the other day). I know the year of depreciation and other issues factor in, but I would consider a 2019 if I can find the right one (scouring the country without luck yet). But if I compromise, I have seen the truck I want with 3.92 rear axle ratio. I will at most pull a jet ski or lawn tractor. I don't need this feature.

My question is - how much of a fuel economy hit will I take? The stickers print the same, but I wonder if that is true in practice.

Thanks all!
Dave

Ram sent us a 2019 Ram 1500 Laramie Black with the eTorque HEMI and 3.92 gears to pin up against our long-term 2019 Ram 1500 Laramie Sport with the non-eTorque HEMI with 3.21 gears. We will be reviewing fuel economy later this week, so stay tuned...

 

[Glenn141]

I know a lot of owners are not happy with their MPG, I drove my trade bait Tacoma v6 down to the dealer 60+ miles and averaged 17.5 mpg. Went home in a 2020 Ram hemi CC 4x4 sport Laramie and got 20.4 on the same route. You can say I'm very pleased.

 

[HotHareSpey]

My 1500 with the off road group and a/t tires got 20-24 all day regardless so long as I kept the speed under 75moh

I live in a very hilly area. I have the 321. I drove a Gladiator today as I’m considering a second vehicle. No way I’d pick one over the RAM - so now it’s between another 1500 with the ORG or a challenger unless I get a fill on electric vehicle

If I go with a second 1500 it will be with a 321 as I don’t tow over 7klbs

 

[Billy James]

I get about 16.5 to 17.5 in everyday mixed driving with the 3.92. The best highway mileage I got was about 19.8. (I rarely drive highway) I would not let the 3.92 dissuade you from purchasing a truck unless you are one of those guys who does a lot of highway driving and insists on going 80 to 100 MPH. The 3.92 will do pretty well as long as you keep it below 70 MPH.

 

[Lize]

On 450 mile round trip mostly highway around 60 to 65 got but about 50 miles at lower speeds I got 20mpg in Rebel with 3.92.

As others report I do think MPG improves with mileage, the 450 mile trip ended at around 3000 miles total and I'm now at a shave over 4000. Only done shorter runs though and haven't done another similar long run to compare but its better plus its also colder and takes longer to warm up.

3.92 ought to make it slightly peppier in acceleration but I've never driven a 3.21 to compare.

 

[Timeless]

I believe most people drive too fast to get anywhere near the best mileage. Eco mode won't even come on unless you are coasting downhill when above 70 MPH.

However if you do drive anywhere near the speed limit you practically become a road hazard these days.

 

[Lize]

I hardly ever saw my Eco mode come on when I first got the truck but gradually it came on more frequently and also for longer. Now at 4000 miles I can actively get it to come on with light throttle and keep on. On saying that I generally have a heavy foot and don’t bother about it.

 

[Willwork4truck]

I believe most people drive too fast to get anywhere near the best mileage. Eco mode won't even come on unless you are coasting downhill when above 70 MPH.

However if you do drive anywhere near the speed limit you practically become a road hazard these days.

I resemble that remark about driving the speed limit...

I think the 3.21 vs 3.92 topic has been hashed over already ad naseum for power, towing, resale, mpg etc.
It isn’t going to break anyone financially to get a 3.92 if you like the truck. Now if you have to give up other options that you want then leave the gears as a lower item of importance if you don’t tow heavy.

I was going to buy a 3.92 till I found a 3.21 locally that fit the bill. If I had bought the 3.92 I’d like it just as well (non-tower). If I towed much at all I’d probably have liked it better.

 

[rws1944]

I resemble that remark about driving the speed limit...

I think the 3.21 vs 3.92 topic has been hashed over already ad naseum for power, towing, resale, mpg etc.
It isn’t going to break anyone financially to get a 3.92 if you like the truck. Now if you have to give up other options that you want then leave the gears as a lower item of importance if you don’t tow heavy.

I was going to buy a 3.92 till I found a 3.21 locally that fit the bill. If I had bought the 3.92 I’d like it just as well (non-tower). If I towed much at all I’d probably have liked it better.

Agree with you on this one. If mileage is that big of a concern don't buy a full size truck.

 

[HotHareSpey]

Agree with you on this one. If mileage is that big of a concern don't buy a full size truck.

It’s always a concern. No one likes a pig. Is it a deal breaker? Visit the Rebel thread . . .

I don’t drive fast unless it’s on the highway as the heat is high here. Johnny Law is everywhere and loves making towns cash

 

[Willwork4truck]

It’s always a concern. No one likes a pig. Is it a deal breaker? Visit the Rebel thread . . .

I don’t drive fast unless it’s on the highway as the heat is high here. Johnny Law is everywhere and loves making towns cash

You in Virginia? That whole state is a speed trap...

 

[HotHareSpey]

You in Virginia? That whole state is a speed trap...

No but I’ve been through there plenty and know exactly what you mean. I usually follow the minivan man rule: wait for a male driving a minivan, they always drive at 80mph+ and follow -6mph. They always take the tickets. Leave 3 car lengths between you and them. Like a glove every time day or night

 

[Damion]

My '16 with 3.92 would shift into 8th around 70kph my '19 with 3.21 shifts into 8th around 85-90 kph so having the 3.21 is like having an overdrive gear on top of the 3.92's. while the 3.21 is still in 7th around 80kph the rpms are roughly where my 16 was with the 3.92 in 8th.

 

[Willwork4truck]

My '16 with 3.92 would shift into 8th around 70kph my '19 with 3.21 shifts into 8th around 85-90 kph so having the 3.21 is like having an overdrive gear on top of the 3.92's. while the 3.21 is still in 7th around 80kph the rpms are roughly where my 16 was with the 3.92 in 8th.

I had to read that over twice to catch “kph” vs “mph” in my brain... I at first thought, “holy crap, he goes into 8th at 85mph?”

 

[SpeedyV]

I get about 16.5 to 17.5 in everyday mixed driving with the 3.92. The best highway mileage I got was about 19.8. (I rarely drive highway) I would not let the 3.92 dissuade you from purchasing a truck unless you are one of those guys who does a lot of highway driving and insists on going 80 to 100 MPH. The 3.92 will do pretty well as long as you keep it below 70 MPH.

I’m happy having the 3.92 for reasons other than economy. Unfortunately, here in north Texas, the vast majority of my highway driving is at speed limits of 70 or 75. To your point, this is NOT the optimal range for economy

 

[JTMachineDesign]

I know a lot of owners are not happy with their MPG, I drove my trade bait Tacoma v6 down to the dealer 60+ miles and averaged 17.5 mpg. Went home in a 2020 Ram hemi CC 4x4 sport Laramie and got 20.4 on the same route. You can say I'm very pleased.

I had a similar experience... drove the 100 miles to pickup my 2019 1500 in my 2007 Dakota quad cab 4.7L and got 17 mpg.. drove home in the 1500 w/HEMI and got 21. 12 years difference in tech really showed !

 

[Cueva del Osos]

I just did my first longer drive w/o a trailer (Santa Fe to Denver, RT). Weather was a concern the whole trip (we were driving in the lulls between storms) but I decided it was a perfect chance to explore some of the factors impacting mpg. For record, I drive ‘19 1500 Ltd Hemi w/E-Torque, 3.92 and have BakFlip F1 tonneau, odometer @ 8,000 In 4 months, 2 adult males, 1 45# dog, about 75# food & luggage.

Drive North was moderate cross winds, Speedway mid grade in tank, ACC set @ 78 mph. Santa Fe to Raton drops 2,000 ft elevation, Raton Pass is up 2,000 ft and back down, Trinidad to Pueblo is down another 1,000 ft. We avg’d 19 mpg on that leg.

Filled up with Sams club premium in Pueblo, and drove to Longmont (similar elevation as Pueblo) with about 10 miles of backed-up slow traffic in a construction zone. We avg’d 21.5 mpg on that leg.

Reverse trip, ACC again @ 78 mph with heavy cross/head winds (40-60 mph) and slightly less weight onboard (carrying less food cargo and more food in us!). Had no construction zone back-ups and averaged 15.0 mpg to Pueblo.

Refilled at same Sams club in Pueblo with same premium. Drive to Santa Fe frequently saw shift to 7th gear to hold speed into wind (6th gear frequently on any uphills). Avg’d 14 on that last leg.

Lesson for me (when not towing): wind is the single greatest factor affecting mpg on this truck. Axle, E-Torque, fuel, tonneau(?) all affect maybe 1 mpg, but wind alone cut my mileage 7 mpg (or 30%).

I hadn’t driven the 1500 in this level of wind before and was quickly concerned by the movement/ noise from the leeward side front door window. The side taking the wind was silent, but there seemed to be a low pressure created on the other side that seemed to be sucking the window outward and creating a really loud wind roar/sucking sound. I could see the glass and plastic (front bottom corner by side view mirror) vibrating/”breathing” during these loud periods. It’s clear that the inside of the glass has more structural support/ trim cover than the outside, but the top of the window IS in its track... so I suspect the entire upper door portion was flexing just a pinch to allow that level of wind noise. Wind lull or totally head wind had noise levels back to usual silence in the cab. (Anyone know if putting rain shields over windows would counter that noise effect?)

The wind impact on this drive agrees with my similar observation while towing - but i wasn’t sure at that time if it was only trailer-induced. Now I know that both truck and trailer are severely impacted by wind (Knowledge that will be helpful when we’re off on a 5 week trip in spring).