An Engineer's Ultimate Guide To 3.21 VS 3.92 Axle Ratio

[CogitoErgoLevo]

I enjoy goofing around in this thread knowing that the relevant info is in the thread's first post.
I bought my truck off the lot, it had the options i wanted. Unfortunately the dealership ordered all their limiteds with 3.92 gears. They tried to justify that by saying limiteds are very heavy and 3.92 helps make them feel less sluggish and that limited buyers don't mind the mpg hit. I test drove both and could not tell a difference.
I would have preferred the 3.21 for better highway mpg but it was not a deal breaker. I don't tow, i do very mild off road and not much highway anymore.

 

[Ramroo]

I enjoy goofing around in this thread knowing that the relevant info is in the thread's first post.
I bought my truck off the lot, it had the options i wanted. Unfortunately the dealership ordered all their limiteds with 3.92 gears. They tried to justify that by saying limiteds are very heavy and 3.92 helps make them feel less sluggish and that limited buyers don't mind the mpg hit. I test drove both and could not tell a difference.
I would have preferred the 3.21 for better highway mpg but it was not a deal breaker. I don't tow, i do very mild off road and not much highway anymore.

What ever do you mean about “relevant” info in the threads first post?
.
Yes, I know…

 

[Mountain Whiskey]

But I guess in the "must have 3.92's" world, the Rebel is now a girls truck since it couldn't out perform a Longhorn with 3.21's.

Well, yes, it is.

Seems the 3.21 guys are trying harder to justify their gear set chchoice.

Just covering the shame they truly feel inside.

Seems the 3.92 guys have the most post. I didn’t buy the truck to go fast and if I need to go fast I drive the Mercedes

Mercedes? Well you only get it to go fast once. After you drive it off the cliff to hit top speed but it is finished afterwards.

Yeah, it's all meant, and taken, in a light-hearted manner.

Really?

I'm not bashing any of the trucks.

I am!

 

[Bigzway]

This thread reminds me of a movie with Lloyd Christmas and Harry Dunne as the post by the 3.92 guys. LOL

 

[theblet]

It’s fun and entertaining in here. That is all

 

[Davidbt]

It's been fun watching the pissing match for sure

 

[Dewey]

 

[Renatboost]

Paid attention to this thread for years.
Had 2022 Laramie with 3.21 and now 4 days in 2024 Laramie with 3.92. I noticed the difference on latest test drive and wanted the difference. Glad i made the change however work pays for the gas!

 

[Scram1500]

It's 3.21 pride day! Wave your flags!

 

[2021EcoDiesel]

It's 3.21 pride day! Wave your flags!

Just you wait until the 92nd of March, my flag will be waving!

 

[Willwork4truck]

It's been fun watching the pissing match for sure

I’d take either one if you gave me the title and keys…. I do admit that my grocery getter 3.92 Ltd gets 3 mpg worse on average than my 2019 Ltd 3.21 got. The “extra take-off” help means zippo to me, being a non-tower.

I also don't get just what the ET hype was/is all about. Now that RAM has dropped the hemi, that ET “experiment” sure didn’t last long. All of that complexity did/does what good/benefit exactly?
Maybe some RAM exec had shares in the 48v battery company or something…

 

[2021EcoDiesel]

I’d take either one if you gave me the title and keys…. I do admit that my grocery getter 3.92 Ltd gets 3 mpg worse on average than my 2019 Ltd 3.21 got. The “extra take-off” help means zippo to me, being a non-tower.

I also don't get just what the ET hype was/is all about. Now that RAM has dropped the hemi, that ET “experiment” sure didn’t last long. All of that complexity did/does what good/benefit exactly?
Maybe some RAM exec had shares in the 48v battery company or something…

Makes me feel odd for having bought an EcoDiesel truck too, only put that motor in the 5th gens for 3 years, suppose that it was just another experiment too .

 

[Willwork4truck]

Seems the 3.21 guys are trying harder to justify their gear set choice.

Id rather have the 3.55’s that they “used” to offer, seems a better compromise. Same with 3.7’s. What’s the problem with giving buyers a better choice of gearsets? Not like it would tremendously complicate ordering or building the truck.
The guy on the assembly lines either reaches into the 3.21 or 3.92 bin… Add one more.

 

[HSKR R/T]

Id rather have the 3.55’s that they “used” to offer, seems a better compromise. Same with 3.7’s. What’s the problem with giving buyers a better choice of gearsets? Not like it would tremendously complicate ordering or building the truck.
The guy on the assembly lines either reaches into the 3.21 or 3.92 bin… Add one more.

Cost. Having to have more overhead for a gear set that wasn't as popular. But IIRC, the 3.55 has always been an option with the V6s, and then the TRX, so at that point, it's just a check in the box, and wouldn't add any cost

 

[Idahoktm]

Cost. Having to have more overhead for a gear set that wasn't as popular. But IIRC, the 3.55 has always been an option with the V6s, and then the TRX, so at that point, it's just a check in the box, and wouldn't add any cost

The 3.55 gear set for the TRX isn't the same as the one for the V6.

 

[2021EcoDiesel]

When I ordered my truck all three gear sets were on the order sheet, however only the 3.92 was available with the E Locker, so that’s the box I checked

 

[Mountain Whiskey]

Id rather have the 3.55’s that they “used” to offer, seems a better compromise. Same with 3.7’s. What’s the problem with giving buyers a better choice of gearsets? Not like it would tremendously complicate ordering or building the truck.
The guy on the assembly lines either reaches into the 3.21 or 3.92 bin… Add one more.

You could put 35s (you know, truck sized tire) on your truck with 3.92s and be real close to 3.55...

 

[Idahoktm]

You could put 35s (you know, truck sized tire) on your truck with 3.92s and be real close to 3.55...

Yep.



Look what happens when you install truck sized tires with 3.21 gears.

 

[Willwork4truck]

Ahh, from a Nov 2023 info blurb from Stellantis, the 3.55 is back in the lineup for the new 2025. I can sleep at night now…

07 Nov 2023

New 2025 Ram 1500 with More Powerful, More Fuel-efficient Hurricane Engine Family Unveiled​

“…Ram 1500 offers a 3.21, 3.55 or 3.92 axle ratio allowing customers to optimize fuel economy and vehicle capability.”

So I guess this “short“ thread will disappear.
What’s left to argue over? Oh right, oil…

 

[Rick3478]

The guy on the assembly lines either reaches into the 3.21 or 3.92 bin… Add one more.

You make it sound trivial, but "reaches into the ... bin" is probably an excessive under-statement of the situation. On the assembly line, it's probably entire axle assemblies that have to be stored on fairly large racks. And with 2WD and 4WD, that means two sets of extra racks. And bigger machines with longer reach to pick the axles off the racks and place them. And more floor space for all that. And an extra thing to consider when it comes time to program the ECU and TCU farther down the line. "Add one more" isn't just linear addition, it's more geometric like adding another dimension to the puzzle.