3:21 vs 3:92 Gears

[SnowBlaZR2]

This is an entertaining thread to say the least ...however I do have a question since I am new to the world of trucks & gearing options.

Does the slight mpg advantage of the 3.21 I keep reading about really only occur when driving at hwy speeds like 65mph+ or even at much lower speeds?

Where I live the "hwy" speed limit is 40 lol and most other roads are 20...so all my driving is like 25-50mph tops. I ordered a 3.92 just because I thought it would feel a bit more more fun to drive on pavement and when I hit some of the hilly dirt roads we have...and in case I eventually buy a boat and need to tow once in a while.

Not concerned really about mpg...but just curious?

Any alleged fuel savings for the 3.21s on the highway are easily wiped out when the truck is overworked trying to accelerate with those inferior gears.

Besides, I still haven't seen 3.21s hit these numbers...

 

[Islander]

You are not getting any better milage with taller gears driving around on a rock in the ocean. You got the right gears. You have flexibility to do as you please.

Puuuuurfect! I guessed right then...thanks!

 

[Dewey]

Any alleged fuel savings for the 3.21s on the highway are easily wiped out when the truck is overworked trying to accelerate with those inferior gears.

Besides, I still haven't seen 3.21s hit these numbers...
View attachment 127929

I coasted down the Beartooth in Yellowstone and easily doubled that with 3.21’s.

Going up was a ***** and would be with 3.92’s as well.

 

[SnowBlaZR2]

I coasted down the Beartooth in Yellowstone and easily doubled that with 3.21’s.

Going up was a ***** and would be with 3.92’s as well.

Post it.

 

[Dewey]

Post it.

Post what? Me coasting downhill and never touching the gas?

It was a joke.

 

[petersandler]

Don't be bummed. The 3.21 gears go perfectly with your Wonder Bread PJ's.

You wish you had a Ricky Bobby racing suit!

 

[SnowBlaZR2]

Post what? Me coasting downhill and never touching the gas?

It was a joke.

 

[Dewey]

Yes I do and now my playtime is done. I have work to do. Have a nice night sir.

 

[wallyuwl]

3.92 have 400ish higher RPM at 70 mph. Almost all the complaints I have seen of really bad mpg are with 3 92. If acceleration off the line is the reason for the 3.92 and not towing or wanting to put on 35s, get a pedal commander or similar.

 

[Mountain Whiskey]

Replace the Prius tires with truck tires and you are at 200-300 rpm different. Keeping it from lugging along. If you believe that is killing you go for it.

@SnowBlaZR2 pointed out earlier that you are saving gas by not working so hard to get moving.

 

[theblet]

Come on let’s hit 2000 posts!

 

[c3k]

This is an entertaining thread to say the least ...however I do have a question since I am new to the world of trucks & gearing options.

Does the slight mpg advantage of the 3.21 I keep reading about really only occur when driving at hwy speeds like 65mph+ or even at much lower speeds?

Where I live the "hwy" speed limit is 40 lol and most other roads are 20...so all my driving is like 25-50mph tops. I ordered a 3.92 just because I thought it would feel a bit more more fun to drive on pavement and when I hit some of the hilly dirt roads we have...and in case I eventually buy a boat and need to tow once in a while.

Not concerned really about mpg...but just curious?

Sure, it'll do just like you want, and in your case it's a great choice. However, and I'm speaking as a 3.21 EcoDiesel guy...you'll be stopping for gas about every 2,000 feet. But, for those 2,000 feet, you'll feel the oomph.

 

[IvoryHemi]

My truck has 3.21 rear...but because of this thread, I'm going to write 3.92 in sharpie on the diff cover so anyone following me will see it and be fooled.

Could just get a decal

 

[ChrisID]

I own both. '21 3.2 and '20 3.9. I tow 6500 TT w/3.2 and it did great, only little compliant is it shifts 3 through 7 all day up and down in the mid-Atlantic hills. Not the end of the world. My 3.9 does this much less, that's all.
The way I drive, with a heavy foot, my 3.9 actually gets 1-2 better mpg overall.
My next rams will always be 3.9, but only cause it's a little better (for me). And the 3.9 does feel a little snappier all around.
Either way, put your foot down and enjoy.

 

[bigdodge]

I own both. '21 3.2 and '20 3.9. I tow 6500 TT w/3.2 and it did great, only little compliant is it shifts 3 through 7 all day up and down in the mid-Atlantic hills. Not the end of the world. My 3.9 does this much less, that's all.
The way I drive, with a heavy foot, my 3.9 actually gets 1-2 better mpg overall.
My next rams will always be 3.9, but only cause it's a little better (for me). And the 3.9 does feel a little snappier all around.
Either way, put your foot down and enjoy.

and what kills transmissions?
heat from shifting "all day up and down"


to each their own
what I do not understand is why the 3.21's are knocking the 3.92's and vice versa
if you are happy with what you have leave us 3.92's alone

 

[theblet]

I own both. '21 3.2 and '20 3.9. I tow 6500 TT w/3.2 and it did great, only little compliant is it shifts 3 through 7 all day up and down in the mid-Atlantic hills. Not the end of the world. My 3.9 does this much less, that's all.
The way I drive, with a heavy foot, my 3.9 actually gets 1-2 better mpg overall.
My next rams will always be 3.9, but only cause it's a little better (for me). And the 3.9 does feel a little snappier all around.
Either way, put your foot down and enjoy.

That's why if you are towing heavy, the 3.92s are better. If not, 3.21s are fine and get a little better mpg if you drive normal.

 

[petersandler]

and what kills transmissions?
heat from shifting "all day up and down"


to each their own
what I do not understand is why the 3.21's are knocking the 3.92's and vice versa
if you are happy with what you have leave us 3.92's alone

I’d say it’s the other way around. The 3.92 posts here claim they get faster acceleration, heavier towing AND better gas mileage. If all three of those statements were indeed true, they wouldn’t offer a 3.21.

The absurdity of the entire debate is the inability of both sides to just admit that each option has a real purpose. It’s why they offer OPTIONS.

Next thing you know is people will be arguing 33 gallon gas tank vs 26 gallon tank.

 

[mikeru82]

Next thing you know is people will be arguing 33 gallon gas tank vs 26 gallon tank.

That's been done already.
But to be fair, so has the 3.21 vs 3.92 thing.

 

[SnowBlaZR2]

If all three of those statements were indeed true, they wouldn’t offer a 3.21.

You don't think they'd offer an option that's not quite as good as something else?

Next thing you know is people will be arguing 33 gallon gas tank vs 26 gallon tank.

You didn't even list the right answer.

 

[c3k]

I have the 33 gallon tank. But I only fill it to 26, because my 3.21 gears need the lighter load.