3:21 vs 3:92 Gears

[IvoryHemi]

I had a Durango with the 5.7L/ 8-speed combo and 3.09 axle ratio. I was expecting to feel a big difference with the Ram’s 3.92 axle, but surprisingly not so much.

Maybe it’s the Ram’s extra 300 lb curb weight plus the 22” wheels that offset the ratio difference. Either way I’d get 3.92 again for towing purposes

 

[grooves12]

They lines are "crossing" at 2600 rpm, but the values aren't. There are two different scales on the graph, scale on the left is the TQ, Scale on the right is HP.

At 5250 RPM looking at the correct scales, It is at about 350 for both HP and TQ. I'm guessing it's done to make the HP curve appear to have a higher peak and the torque curve to look flatter. AS At 2600 RPM where they cross on the graph, it actually is showing 150HP/350TQ when looking a the respective scale for each value.

 

[Mountain Whiskey]

Guys with 3.21 know for a fact, beyond a shadow of doubt that the 3.21 is faster, more powerful and gets good mileage.

Guys with 3.92 know for a fact, beyond a shadow of doubt that the 3.92 is faster, more powerful and gets just as good of milage as 3.21.

Personally I don't have either. Yet. I ordered mine with 3.92. I plan a lift and 35's. I figure the lower gear will help with that. My jeep has 4.10 with 35's and I love it. I have a Town Car that came with 3.08 rear and I changed it out to 3.73. I love to tinker and thought I would order the lower gears rather than change them later.

 

[theblet]

I don’t tow often, just commute and use the bed. So I went with 3.21s. Nice to have the best mpg possible.

 

[z0n3]

I don’t tow often, just commute and use the bed. So I went with 3.21s. Nice to have the best mpg possible.

Exactly the reason I went with 3.21. Would I like to have 35” tires? Sometimes. But the 3.21 is fantastic with aftermarket wheels and 33s and I retain decent mileage and can still tow if absolutely necessary.

 

[theblet]

Exactly the reason I went with 3.21. Would I like to have 35” tires? Sometimes. But the 3.21 is fantastic with aftermarket wheels and 33s and I retain decent mileage and can still tow if absolutely necessary.

Yes sir. This truck will tow just fine. You should have seen what my 205 hp 5 cylinder Colorado pulled with 3.05 gears

 

[Willwork4truck]

Took delivery of my 2021 Ram Limited E-torque V-8 with 20" rims & 3:21 gears yesterday. I am thrilled with my decision to go with the 3:21 rear gears over the 3:92. Maybe it's because I had a HD2500 Diesel before but this truck has all the off the line power I can imagine needing.

Glad you are happy with it, gears was the hardest decision I had to make of the entire purchase, kind of crazy when you think about it.

 

[IvoryHemi]

I think only $95 makes 3.92 an easy decision for many. It would be different if FCA charged $595 like they did for 4.10 on Wrangler

 

[Willwork4truck]

Yes sir. This truck will tow just fine. You should have seen what my 205 hp 5 cylinder Colorado pulled with 3.05 gears

I don’t know, maybe we wouldn’t have wanted to see what you towed with your Colorado...

 

[Willwork4truck]

Took delivery of my 2021 Ram Limited E-torque V-8 with 20" rims & 3:21 gears yesterday. I am thrilled with my decision to go with the 3:21 rear gears over the 3:92. Maybe it's because I had a HD2500 Diesel before but this truck has all the off the line power I can imagine needing.

That was actually the thing that caused me more angst, trying to decide to order the 3.21 vs the 3.92.
Course the wife settled that when she found her colors, it could have been a Ridgeline if it was tri-tone ivory with the cream interior...

 

[BowDown]

Glad you are happy with it, gears was the hardest decision I had to make of the entire purchase, kind of crazy when you think about it.

The gear choice was the easiest decision for me, complete no brainier.

 

[Buz]

I put the next size up tires on my 3.92 (275/60-R20)
So now I have a 3.79 rear.
I like the compromise and it shaved a few RPM's off the tach on the interstate.
MPG has stayed the same (recalbrated the speedo) so I'm guessing the slightly lower RPM's cancels out the slightly heavier tires.

 

[PeteyK49]

I test drove both and didn’t notice much of a difference except when I turned traction control off and spun the tires. The 3.92 had more ummph off the bottom but not enough for the loss of mpg. At highway speeds they felt the same for me but I wasn’t hauling anything during the test drives. I drove as I normally would. The 8 speed transmission seems to takes away the gear change effect I got in my 4spd f150 when I went from 3:73 to 4:10’s. I don’t tow often. I haul stuff for around the house, hunting gear and quads. If I do buy a camper it will be a light weight setup so I don’t have to get a HD truck. I’ve had my truck less than a week and have averaged 16.5 mpg with the 3.21’s in the 330 miles I put on it. That’s better than the 10-12mpg I was getting around town with my 07 f150

 

[TNRamGuy]

when I was deciding I test drove 4 different trucks, the etorque both of them twice each.
I drove the hemi e with 3.21, hemi e with 3.92, hemi non e with 3.92 and a diesel. I liked all the hemi's (diesel is just not for me apparently) the difference between 3.21 and 3.92 was barely noticeable and the etorque seemed slightly smoother to me. nothing based on science, or numbers, or anything other than how it gelled with my driving style. I would highly recommend anyone doing the same thing. the sales guy got sick of riding with me and just handed me 2 sets of keys and told me to come find him when I was done. I am happy with mine and glad I spend the hour doing it.

 

[silver billet]

My truck spends it's entire life in park and 8th. The other gears are just there to get me back and forth. Complete no brainer in my case, and this truck is the most powerful vehicle I've owned to date. No regrets (though I'm flirting with the idea of going diesel).

 

[Quint]

My 2015 had 3.21 gears. It towed my 90hp 16.5ft Alumacraft boat loaded with 2,200lbs of concrete and other supplies for 250 miles with zero problem. I loved the highway mileage. My 2021 with 3.92 gears definitely has more low-end grunt. However, even pulling my 2-place snowmobile trailer with sleds, it will hunt between 6th & 7th gears on Minnesota highways when I hit rolling hills.

For what I do, I wish there would have been more options on the lot with 3.21 just because I would rather have the mileage. If I was towing much heavier trailers then maybe I would have truly wanted 3.92 gears.

 

[Willwork4truck]

The gear choice was the easiest decision for me, complete no brainier.

Had I been towing I’d agree.

 

[Willwork4truck]

My truck spends it's entire life in park and 8th. The other gears are just there to get me back and forth. Complete no brainer in my case, and this truck is the most powerful vehicle I've owned to date. No regrets (though I'm flirting with the idea of going diesel).

I get that though ours is more like in Park...

 

[IvoryHemi]

I have a 2021 Big Horn with 3:21’s. Right now , I have the stock wheels and tires (18” wheels with 275/65R18 Goodyear Wrangler Fortitude HT’s) and I’m having new wheels and tires put on next week (20” XD Monster rims with 275/55R20XL Nitto 420V’s). The difference in height is just over an inch increase with the new wheel/tire setup. Will I notice a difference in acceleration or mpg?

Unless your new setup weighs a lot more then stock, you probably won’t notice

 

[Buz]

I have a 2021 Big Horn with 3:21’s. Right now , I have the stock wheels and tires (18” wheels with 275/65R18 Goodyear Wrangler Fortitude HT’s) and I’m having new wheels and tires put on next week (20” XD Monster rims with 275/55R20XL Nitto 420V’s). The difference in height is just over an inch increase with the new wheel/tire setup. Will I notice a difference in acceleration or mpg?

Actually the difference in height from the two sizes you listed is negligible at about .2 of an inch. Your new tires are just slightly smaller in circumference. Your 3.21 rear will now be 3.23 No need to recalibrate your speedo.
Not sure what your standard tire pressure is with your OEM 18’s but if it’s 36psi you’ll need to run 41psi in the new ones for similar loading performance.
Your ride will suffer a bit.