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

[JF19Longhorn]

Thanks for the data. Confirms my choice was right.

 

[csmith2007]

Basically if you pull heavy it will take an extra second or two to get out of first gear. If you are pulling 5000 plus pounds what is the hurry?

 

[DesertRebel]

I feel like a lot of people like the 3.92 for that 0-30 towing gear. It gives you better acceleration off the line which makes the truck drive a bit more sporty. That may be why some people call the 3.21 "slow" or "sluggish" (even though there isn't THAT much difference).

^^^This exactly.

With any of my vehicles I want the shortest rear dif gears possible... zero to where I want to be swiftly.

 

[ppowell1983]

Awesome information and great explanation.


Sent from my iPhone using Tapatalk

 

[Nails]

Great right up, much appreciated!!

 

[Chippy]

All you idiots chiming in here saying this ones for me or I picked right please get a life.
To the OP thank you for putting it together so people are informed.

 

[raven_DT]

What about the 3.42s???

 

[DesertRebel]

All you idiots chiming in here saying this ones for me or I picked right please get a life.
To the OP thank you for putting it together so people are informed.

Why would someone commenting on their choice - be considered an idiot?

 

[Flyrod11ft]

Great job writing that up. I have the 3.92, tow a boat, and could have gotten away with 3.21 gears but the truck had everything I wanted and had 3.92’s so thats what I have now. Again thanks for taking the time to do this

 

[NTX_Ian]

All you idiots chiming in here saying this ones for me or I picked right please get a life.
To the OP thank you for putting it together so people are informed.

Sounds like u got a chip on ur shoulder there Chippy.

Thanks OP, data is a beautiful thing.

 

[magic280z]

I went from a 3.21 4th gen to a 3.92 5th Gen both 8 spd. I believe there is no reason the 3.21 shouldn't feel the same most of the time, but the shift programming is just too aggressive. The 3.92 seems to include some extra play that makes the aggressive upshifts more tolerable or the programming is better now. The local inventory was mostly 3.92 this time so I never test drove a 5th Gen 3.21.

Also the 3.21 8 spd in first is still better than the 3.92 6 speed in first.

If Ram would give us a sport mode they could solve so many issues.

2019 Ram 1500 Laramie - Crew Cab/5.7 Bed - 5.7 Hemi - 3.92 - Anti Spin - Level 1 Options - RamBox - BUG

 

[SacRebel]

Any idea on what the gas mileage difference is between a 3.21 and a 3.92?

 

[DesertRebel]

Any idea on what the gas mileage difference is between a 3.21 and a 3.92?

Seems to vary widely - even between same gear ratio

 

[Magnetic]

Using the data provided, it appears that at lower non-highway speeds where the 3.92 stays in gear 4,5,6,7 or 8 that it would be slightly more fuel efficient than a 3.21 in gear 3,4,5,6 or 7….

 

[Rampat]

Why would someone commenting on their choice - be considered an idiot?

Because some people are *******s and want to make you feel bad. Ignore that guy.

 

[Rob5589]

Using the data provided, it appears that at lower non-highway speeds where the 3.92 stays in gear 4,5,6,7 or 8 that it would be slightly more fuel efficient than a 3.21 in gear 3,4,5,6 or 7….

A lower gear ratio can improve mileage in a towing situation. I have done several gear swaps to improve towing performance, and many have seen an increase in mpg.
A gear swap simply puts the engine in a better torque range so the engine has to struggle less to keep a certain speed/momentum. It also allows the engine to reach a certain rpm quicker which leads to more efficient power delivery.
The advent of 6+ speed transmissions has changed the need for ultra low gearing. You can get a low 1st (4.xx) and still maintain a reasonable final drive to improve mpg. Not to mention the 8 speed has a much smoother transition gear to gear than the old 3 spd autos.

 

[202snowman]

Please refrain from personal attacks or any other actions that violate the terms and conditions of the site. Thank you.

 

[DesertRebel]

Please refrain from personal attacks or any other actions that violate the terms and conditions of the site. Thank you.

At the risk of perpetuating controversy - I feel compelled to ask... is this regarding the post three days ago?

I'm trying to get a feel for the dynamics of this forum ... all are a bit different and I've found this one to be relatively free from drama... but I think it's in the best interest of all members to know what boundaries are set by site owner(s)...

Due to the nature of Ram Truck owner personalities - maturity and self regulation is almost a given... I've noticed (minimal) adolescent posts - that tend to be ignored... seems to work pretty well.

Sorry for going down the rabbit hole guys - when opportunity to learn strikes, I'm asking (whether about a Ram truck or a Ram truck Forum).

 

[202snowman]

At the risk of perpetuating controversy - I feel compelled to ask... is this regarding the post three days ago?

I'm trying to get a feel for the dynamics of this forum ... all are a bit different and I've found this one to be relatively free from drama... but I think it's in the best interest of all members to know what boundaries are set by site owner(s)...

Due to the nature of Ram Truck owner personalities - maturity and self regulation is almost a given... I've noticed (minimal) adolescent posts - that tend to be ignored... seems to work pretty well.

Sorry for going down the rabbit hole guys - when opportunity to learn strikes, I'm asking (whether about a Ram truck or a Ram truck Forum).

Yes, that was the post that caused me to put the reminder out to everyone in the thread, as 1) people were starting to respond to it and report it to the moderators.

I'd say it this way...no issue with disagreements as long as the conversations stay civil. When it gets personal, vulgar, etc is when I'll step in with a reminder and or other actions.

 

[DesertRebel]

Yes, that was the post that caused me to put the reminder out to everyone in the thread, as 1) people were starting to respond to it and report it to the moderators.

I'd say it this way...no issue with disagreements as long as the conversations stay civil. When it gets personal, vulgar, etc is when I'll step in with a reminder and or other actions.

Understood - thank you for the response.