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

[Mountain Whiskey]

He's probably one of the only dudes who could afford it

That video clip just still gets me. The dead serious answer and then the look on the face of the Fox reporter babe is just priceless.

 

[AngelPhoenix]

That video clip just still gets me. The dead serious answer and then the look on the face of the Fox reporter babe is just priceless.

It's a classic

 

[n8zcc]

Recently, like last week, I traded in my 2013 RAM 1500 for a new 2022 1500. Both trucks have the ZF 8-speed and 3:21 axle ratios. I noticed a difference in the tire aspect ratio between the model years, the 2022 has a 275/55 R20 and my 2013 ran 275/60 R20s. This aspect change caused a reduction in the tire's circumference by just over 3% equating to a rotational increase of 20 revolutions per mile or an engine RPM increase of 55 RPMs at 65 MPH.

I'm wondering why, why did RAM make this change?

While the change will make a slight increase in torque if all the transmission's output ratios remain unchanged, the difference would be unnoticeable. Does anyone know what the ZF 8-speed output ratios are and are the ratios different for an ECODiesel? I've done searches for the ZF's ratios but have come up with different sets of ratios. I'm wondering what the ratios are for the RAM ECODiesel application. Here is what I think is accurate (which is the same as in post #1).

4.710 3.140 2.100 1.670 1.290 1.000 0.840 0.670

 

[IvoryHemi]

Does anyone know what the ZF 8-speed output ratios are and are the ratios different for an ECODiesel?

I've done searches for the ZF's ratios but have come up with different sets of ratios. I'm wondering what the ratios are for the RAM ECODiesel application.

 

[Mountain Whiskey]

Should have just gotten the 3:92s and been happy.

 

[djevox]

Should have just gotten the 3:92s and been happy.

3.21 > 3.92…

 

[ferraiolo1]

I want to tow an enclosed trailer with a track car in it. I opted for the 3.21s. I promise I won’t get butt hurt and leave the forum if you tell me I was wrong.


Sent from my iPhone using Tapatalk

 

[theblet]

I want to tow an enclosed trailer with a track car in it. I opted for the 3.21s. I promise I won’t get butt hurt and leave the forum if you tell me I was wrong.


Sent from my iPhone using Tapatalk

She'll tow it. Don't worry. Enjoy the increased fuel mileage after you're done.

 

[KWKSLVR]

I want to tow an enclosed trailer with a track car in it. I opted for the 3.21s. I promise I won’t get butt hurt and leave the forum if you tell me I was wrong.


Sent from my iPhone using Tapatalk

You'll be fine. My yuppie Limited with 3.21's, ramboxes and MFT is rated to tow 7800lbs which is more than I probably ever will.

 

[theblet]

You'll be fine. My yuppie Limited with 3.21's, ramboxes and MFT is rated to tow 7800lbs which is more than I probably ever will.

3.21's unless you're drag racing.

 

[KWKSLVR]

3.21's unless you're drag racing.

I'd want 4.10's if I was drag racing!

 

[BowDown]

3.21's unless you're drag racing.

And even then a 3.21 truck would gap the dog S out of a limp d 3.92 truck.
Troof

 

[TNRamGuy]

And even then a 3.21 truck would gap the dog S out of a limp d 3.92 truck.
Troof

 

[djevox]

And even then a 3.21 truck would gap the dog S out of a limp d 3.92 truck.
Troof

 

[ferraiolo1]

And even then a 3.21 truck would gap the dog S out of a limp d 3.92 truck.
Troof

True dat! Them fellers with the 3.92s always have them big off roadin power killin tars.


Sent from my iPhone using Tapatalk

 

[Idahoktm]

I want to tow an enclosed trailer with a track car in it. I opted for the 3.21s. I promise I won’t get butt hurt and leave the forum if you tell me I was wrong.


Sent from my iPhone using Tapatalk

I think they missed your sarcasm.

 

[BowDown]

3.92 are todays equivalent of yesterdays

 

[HSKR R/T]

And even then a 3.21 truck would gap the dog S out of a limp d 3.92 truck.
Troof

Guys with 3.21s are too worried about gas mileage to ever be seen racing on a drag strip.

 

[brian42]

I'd just shallow stage to get a jump on the light. The 3.92 truck will tach out in 8th (my 7th) so I'll have an "extra gear" and run them down at the end and take the line by a bumper with the higher trap speed.

 

[KWKSLVR]

I really am confused why we're talking about drag racing trucks. It's like drag racing minivans