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

[Willwork4truck]

Is there a CAT scale near you? Seems like a weight ticket would end this back and forth…

 

[HSKR R/T]

Is there a CAT scale near you? Seems like a weight ticket would end this back and forth…

Or he could just post his GVWR and do some math based on his payload sticker to get his vehicle weight.

 

[Eighty]

Or y'all could just keep arguing about this. That's more entertaining, and it keeps you out of trouble in other places.

 

[Willwork4truck]

Or he could just post his GVWR and do some math based on his payload sticker to get his vehicle weight.

From web site “weigh-safe.com” dated September 28, 2023.
(Begin article quote)

How to Determine Curb Weight​

“For most vehicles, you won’t have to calculate the curb weight on your own. The owner’s manual will usually provide this information, or you may be able to find it on a sticker located within the driver’s door.

However, if you can’t find the curb weight, you can always take the vehicle to a truck stop. These locations have large scales, often used for measuring 18-wheelers, but they can measure any vehicle’s weight. Remove cargo and people from the vehicle to get an accurate weight.

How to Calculate Curb Weight With GVWR​

You can do some math if you still need another option to find the curb weight. Start with the Gross Vehicle Weight Rating (GVWR), your vehicle’s maximum payload capacity. You can find this in the owner’s manual, the driver’s side door sticker, or the manufacturer’s website.

Take the payload capacity and subtract it from the GVWR, giving you the curb weight.“. (End of quoted portion of article.)

 

[SnowBlaZR2]

@SnowBlaZR2 I know what you are getting for your birthday.......

View attachment 176864

I mean...the dude had it coming.

 

[SnowBlaZR2]

Or y'all could just keep arguing about this. That's more entertaining, and it keeps you out of trouble in other places.

Wait...is this trouble? I thought this was a truck forum, not Braxton's soccer game.

 

[theblet]

Well, now I'm just offended. I was not stomping my feet. I was holding my breath and pounding my fists. So there!

Did you pass out?!!!

 

[2021EcoDiesel]

Did you pass out?!!!

@Mountain Whiskey Take a breath, friend!

 

[Mountain Whiskey]

 

[Ramfancy]

You guys need a beer!

 

[theblet]

You guys need a beer!

That’s a fact

 

[Mountain Whiskey]

You guys need a beer!

Beer!? You know beer has yeast poop in it? Distilled alcohol filters the poop out. Liquor for me please!

 

[theblet]

Beer!? You know beer has yeast poop in it? Distilled alcohol filters the poop out. Liquor for me please!

I drank whiskey last night

 

[TheWaterman83]

I have the Rebel with 3.92's. Just out of curiosity, what does everyone with 3.92 turn for RPM at about 75 mph?

Maybe it's just the fact I haven't been on the highway in a while, but, I was doing 75mph today and noticed I was turning 2000 rpm. Seemed a little bit high from what I remember.

 

[Dewey]

I have the Rebel with 3.92's. Just out of curiosity, what does everyone with 3.92 turn for RPM at about 75 mph?

Maybe it's just the fact I haven't been on the highway in a while, but, I was doing 75mph today and noticed I was turning 2000 rpm. Seemed a little bit high from what I remember.

Seems about right. I run 1800 rpm at 75 with 3.21’s.

 

[TheWaterman83]

Seems about right. I run 1800 rpm at 75 with 3.21’s.

Appreciate it. Seems to be about normal.

 

[Ramroo]

I have the Rebel with 3.92's. Just out of curiosity, what does everyone with 3.92 turn for RPM at about 75 mph?

Maybe it's just the fact I haven't been on the highway in a while, but, I was doing 75mph today and noticed I was turning 2000 rpm. Seemed a little bit high from what I remember.

I have a stock 3.21 and 3.92, same size tires 3.21 runs 1750 rpm. 3.92 runs about 400 rpm higher at 2150 rpm.

I have pic for 3.21 I will post, trying to find 3.92 pic (Son drives the 3.92). Your rebel has 33 inch tires that will bring rpm’s down some.

 

[TheWaterman83]

I have a stock 3.21 and 3.92, same size tires 3.21 runs 1750 rpm. 3.92 runs about 400 rpm higher at 2150 rpm.

I have pic for 3.21 I will post, trying to find 3.92 pic (Son drives the 3.92). Your rebel has 33 inch tires that will bring rpm’s down some.

I'm about 2000rpm at 75 mph with the stock tire size so it seems right.

 

[Rick3478]

I have the Rebel with 3.92's. Just out of curiosity, what does everyone with 3.92 turn for RPM at about 75 mph?

Maybe it's just the fact I haven't been on the highway in a while, but, I was doing 75mph today and noticed I was turning 2000 rpm. Seemed a little bit high from what I remember.

Sounds about right. The extra overdrive gear in the ZF transmission makes highway speed more practical for the towing axle.

 

[Mountain Whiskey]

I'm a out 2k at 80mph but I have 35s. Your Reble has 33s right?