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

[TNRamGuy]

I've regeared in the past, my old Charger with a 8 3/4 rear three times and my Z06 once but that was a trans re-gear so I could lengthen some shifts , 2nd, 3rd and 4th are very close and hurt my mile an hour in the 1/4 and 1/2 mile runs. I bought the truck this way intentionally, I sought out a truck with every specific option my truck has, even passed on a close truck because of the 3.93 gear.
The 3.21 suits my needs fine and having had a 392 truck and rented a 5th gen 3.92 and a 3.21 truck a 3 days and a week respectively, I don't miss the 3.92. If it works for you, great, I have to drive Dallas to Houston often and driving that drive at 65-67mph to get decent fuel mileage sucks.

Well played, it's almost like there's no perfect fit

 

[BowDown]

Well played, it's almost like there's no perfect fit

Well to be fair, the Charger was regeared when I re-engined it. Started off as a 318 car then I went to a Racing Head Service 360 on bad advice; many so called mopar heads claimed you could install a B/RB engine in an LA engine car. That was false as I later went to a 440 and with each engine, I came across a better choice of gears so I swapped; 2.73 then 3.23 then 4.30 then back to the 3.23 with the 440.

My Z06 is just a different animal, it makes 720hp NA and has the 3.42 rear but the MN12 close ratio trans. That trans and gear combo are fine with stock power but too much gear at my power level. I broke the output shaft 2 years ago and put stronger shafts in and a different 3rd gear, helped but not enough. I'm switching to ZR1 trans when the engine comes out for a rebuild because I'm having to go to 5th or hold 7800 rpm in 4th in the 1/2 mile run.

As for the truck, I absolutely have no desire to regear it as its perfect to me. I'd rather have the 6.4 engine option than the 3.92 gear option

 

[ferraiolo1]

There certainly is a perfect fit. You buy the truck/gearset that meets your needs. One isn’t better than the other.


Sent from my iPhone using Tapatalk

 

[SnowBlaZR2]

That cant be it as many of you swear there's no mpg difference between the 2

This is what it looks like when you don't order the right option from the start, folks.

 

[BowDown]

This is what it looks like when you don't order the best option from the start, folks.

RIF, I did get the best option for me, for you it may be different. As I said above, I have a 700hp car, I don't need or want this truck to be fast nor will it be with 3.92 gears. The truck performing better is, IMO, a fallacy at worst and negligible at best.
Also as I said above, I passed on 3.92 trucks on purpose so no, I didn't not "order" the best option from the start. I do laugh at people thinking 3.92 makes these trucks rockets though.
But for grins, I'd bet money my 3.21 truck is quicker than most of your 3.92 trucks. I'd bet my truck is 5-700lbs lighter than most of these 3.92, that alone negates your "performance advantage".

 

[SnowBlaZR2]

RIF, I did get the best option for me, for you it may be different. As I said above, I have a 700hp car, I don't need or want this truck to be fast nor will it be with 3.92 gears. The truck performing better is, IMO, a fallacy at worst and negligible at best.

This is stupid. I have a million dollars. I don't need or want a million more...

Also as I said above, I passed on 3.92 trucks on purpose so no, I didn't not "order" the best option from the start. I do laugh at people thinking 3.92 makes these trucks rockets though.
But for grins, I'd bet money my 3.21 truck is quicker than most of your 3.92 trucks. I'd bet my truck is 5-700lbs lighter than most of these 3.92, that alone negates your "performance advantage".

I mean, it's no more funny than 3.21 weenies claiming significant fuel savings.

Also, lol at the little guy offer to "run them." Reminds me of the 1911 "just as gud" crowd.

 

[KWKSLVR]

I do agree that it's silly for anyone to find these trucks fast. They have a torque, and torque makes things feel quick, but they are what they are. They're bricks on wheels with above average acceleration with either gear set. Average is still slow and so is above average. That said, I drive like a grandpa. I got all the speed demon out of my system in and right after college. I wrenched on and drove plenty of 10 - 11 second 1/4 mile vehicles. They're a blast, but these days I just want to leave early, get where I'm going early and pretty much avoid the moronic actions of everyone else on the road.

I think doing a ton of stupid crap in your youth brings that side of things out when you're older. Also, for my Limited, my payload is so low that I don't think 3.92's would bump my max tow up all that much. At the end of the day, if I was going to do a bunch of serious towing I would have ordered a 2500 and made it all easier on myself.

But that's too much serious talk for a fun thread. In the meantime I'm gonna laugh at all the 'necks with 3.92's, jacked up trucks rolling on 35's impressing no one. Gotta blow that tax return on something other than savings!

 

[KWKSLVR]

This is stupid. I have a million dollars. I don't need or want a million more...


I mean, it's no more funny than 3.21 weenies claiming significant fuel savings.

Also, lol at the little guy offer to "run them." Reminds me of the 1911 "just as gud" crowd.

I dunno man, the number of 3.92's posting about 12-14mpg is pretty high and I rolled home from Louisiana getting a lot more than that with under 1K on the odo.



And that's after idling for 10 minutes in a drive thru waiting for my Americano. Thank you, eTorque!

 

[SnowBlaZR2]

I would have ordered a 2500 and made it all easier on myself.

The sunroof in the 2500 sucks.

 

[SnowBlaZR2]

I dunno man, the number of 3.92's posting about 12-14mpg is pretty high and I rolled home from Louisiana getting a lot more than that with under 1K on the odo.

View attachment 121640

And that's after idling for 10 minutes in a drive thru waiting for my Americano. Thank you, eTorque!

20.2 MPG for mine when I'm not towing, but I don't drive it hard. Can't blame the 3.92s for getting on their trucks in a way the 3.21s wish they could.

 

[BowDown]

This is stupid. I have a million dollars. I don't need or want a million more...


I mean, it's no more funny than 3.21 weenies claiming significant fuel savings.

Also, lol at the little guy offer to "run them." Reminds me of the 1911 "just as gud" crowd.

If you think its stupid then I'm fairly sure you've not owned a car with true power. It gets old sometimes, driving around on drag radials everywhere because street tires spin in the 1st 4 gears with barely any throttle input. My Z06 makes 430 lbft of tq at 2400 rpm in a 3100lb car with a twin ceramic disk clutch. It gets tiring and every time I get in this truck, the last thing I want is fast.
Always easy to tell those who've tasted power and those who haven't.

As for the 3.21 savings, thats be proven so its no claim. to the weenies part, you think 3.92 changes anything in performance? Holy S that's funny, this truck will never be fast, a TRX isnt fast.

 

[KWKSLVR]

The sunroof in the 2500 sucks.

I think all sunroofs suck. Avoiding one was a big reason I wanted to custom order. Between the road noise, leaky cabins and eventual squeaks and pops that will come with body flex with anyone that drive's their truck like a truck off-road, I prefer to take a hard pass on them these days. They're cool but on our vehicles with sunroofs, they get opened maybe 3 times a year.

I can't imagine why anyone with 3.92's that thinks their truck could qualify for nascar would want one.

 

[BowDown]

I dunno man, the number of 3.92's posting about 12-14mpg is pretty high and I rolled home from Louisiana getting a lot more than that with under 1K on the odo.

View attachment 121640

And that's after idling for 10 minutes in a drive thru waiting for my Americano. Thank you, eTorque!

No S, far more threads about poor mileage from 3.92 guys than anyone else, period.
Side note, jealous of the utility of UC 5. Whish they'd upgrade UC 4 or is that an app on your phone?

 

[Scram1500]

I'd rather have the 6.4 engine option than the 3.92 gear option

Truth!

 

[TNRamGuy]

I dunno man, the number of 3.92's posting about 12-14mpg is pretty high and I rolled home from Louisiana getting a lot more than that with under 1K on the odo.

View attachment 121640

And that's after idling for 10 minutes in a drive thru waiting for my Americano. Thank you, eTorque!

Omg, as if it wasn't bad enough that your interior is sea salt, now you're showing off pages that don't exist for us pesent 21 and earlier owners

 

[BowDown]

20.2 MPG for mine when I'm not towing, but I don't drive it hard. Can't blame the 3.92s for getting on their trucks in a way the 3.21s wish they could.

20.2 at 65mph Lol

 

[SnowBlaZR2]

If you think its stupid then I'm fairly sure you've not owned a car with true power. It gets old sometimes, driving around on drag radials everywhere because street tires spin in the 1st 4 gears with barely any throttle input. My Z06 makes 430 lbft of tq at 2400 rpm in a 3100lb car with a twin ceramic disk clutch. It gets tiring and every time I get in this truck, the last thing I want is fast.
Always easy to tell those who've tasted power and those who haven't.

As for the 3.21 savings, thats be proven so its no claim. to the weenies part, you think 3.92 changes anything in performance? Holy S that's funny, this truck will never be fast, a TRX isnt fast.

Lol, who said you should put drag radials on your Ram? I'm just saying that "I have a 700 hp car" is a stupid excuse for neutering your truck. Of course, you did go with 2wd, so I'm hesitant to even call that a truck.

As for the 3.21 savings, thats be proven so its no claim. to the weenies part, you think 3.92 changes anything in performance? Holy S that's funny, this truck will never be fast, a TRX isnt fast.

I'll be in San Antonio at the end of the month. Meet me at noon on Feb 31st and we'll run them so you can see what real power actually looks like. I'll be at I-10 and 130 waiting. Bring the Vette if you want because I know that doesn't have 3.92s, either.

 

[BowDown]

Omg, as if it wasn't bad enough that your interior is frost, now you're showing off pages that don't exist for us pesent 21 and earlier owners

Yeah, thats a D move

 

[SnowBlaZR2]

20.2 at 65mph Lol

I wouldn't have a license if I drove 65mph around town regularly.

 

[KWKSLVR]