The best rear axle ratio for me

[IvoryHemi]

I think the ET, even if it only gets the truck moving from a stand still for a couple tire rotations

ET doesn’t give a couple rotations.

As @mikeru82 said, it’s 49 lb-ft only gives you 1/2 of the first tire rotation.

 

[Johnny_H]

Of course, but that's because they're definitely above the GVWR of their truck.

I'd feel pretty confident towing 11k with this truck if I ever had the need, so long as I was by myself and it wasn't a payload killer like a 5th wheel.

Exactly. Unless that 11k load has some abnormally low tongue weight you’re gonna be over payload on most of these trucks unless you have a 2wd big horn.

I guess what I’m saying is if 8k isn’t enough for you, you probably should be looking at a 2500. The 5.7 is a great motor but these trucks are sofffffft.


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[SnowBlaZR2]

Exactly. Unless that 11k load has some abnormally low tongue weight you’re gonna be over payload on most of these trucks unless you have a 2wd big horn.

I guess what I’m saying is if 8k isn’t enough for you, you probably should be looking at a 2500. The 5.7 is a great motor but these trucks are sofffffft.


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At 10-12% on a properly loaded flatbed or dump trailer you're looking at 1100-1300 lbs or so, which I'd have no problems pulling if I was alone.

If I towed something like that a couple times a year, I wouldn't jump to a 2500 and lose the luxury of my 1500.

 

[Johnny_H]

Yeah totally makes sense. Hauling 12k pounds to the dump isn’t a big deal, but a 9k TT with your family through the mountains might be.


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[Ninety-9 SE-L]

All you had to say.

Yea, Yea. Still, I question anyone who says the 3.92 is better on the highway. Set your gear limit to 7 and you basically have the same truck, at highway speeds.

I just disagree that you would get 2mpg benefit as I haven’t seen it in comparable trucks I’ve driven, but it’s certainly possible under certain driving conditions.

Might be overblown. I'll add my numbers to the mpg thread when I start driving it. It's rare enough to find a member with a 4x2 EcoDiesel, let alone a 3.21.

It's a little more than 500 lbs.

For the most popular configuration, the difference is 8,110 lbs vs 11,210 lbs.

For my build, it goes down a chunk, but it's still within what I need to tow.

Also, I think that towing/payload ratings are overly conservative. I think federal ratings are mostly based on the fact that most idiots will be blasting down the highway, going 80 at their maximum payload.

Yeah totally makes sense. Hauling 12k pounds to the dump isn’t a big deal, but a 9k TT with your family through the mountains might be.

Living and mostly driving in Florida has its advantages.

 

[SnowBlaZR2]

Yea, Yea. Still, I question anyone who says the 3.92 is better on the highway. Set your gear limit to 7 and you basically have the same truck, at highway speeds.

Might be overblown. I'll add my numbers to the mpg thread when I start driving it. It's rare enough to find a member with a 4x2 EcoDiesel, let alone a 3.21.



For my build, it goes down a chunk, but it's still within what I need to tow.
View attachment 124094
Also, I think that towing/payload ratings are overly conservative. I think federal ratings are mostly based on the fact that most idiots will be blasting down the highway, going 80 at their maximum payload.

Living and mostly driving in Florida has its advantages.

Sure they're conservative, but they're equally conservative. I look at it like this. My wife and I can both lift 50 lbs. If we only do that once a day, and one day a year, big deal. But if we do it 100 times a day, every day of the year, she's going to get tired faster than I am and she's going to wear out before I do. She's just not as strong or big as I am, and it'll eventually show if we do enough work. The 3.21s might pull heavy loads, but they're never going to be as good at moving them as 3.92s.

Now sure, if you press this button, and hold the throttle at that position, and make sure you fart out the sliding glass window instead of the sunroof, the 3.21s can give you similar performance in some situations. Or, just get the right gears from the start and hit the gas pedal when you want to go.

 

[Johnny_H]

Sure they're conservative, but they're equally conservative. I look at it like this. My wife and I can both lift 50 lbs. If we only do that once a day, and one day a year, big deal. But if we do it 100 times a day, every day of the year, she's going to get tired faster than I am and she's going to wear out before I do. She's just not as strong or big as I am, and it'll eventually show if we do enough work. The 3.21s might pull heavy loads, but they're never going to be as good at moving them as 3.92s.

Now sure, if you press this button, and hold the throttle at that position, and make sure you fart out the sliding glass window instead of the sunroof, the 3.21s can give you similar performance in some situations. Or, just get the right gears from the start and hit the gas pedal when you want to go.

You and your wife don’t have the same hemi, transmission, and suspension components either. The diff is more analogous to a longer lever such as you having longer arms than your otherwise identical twin brother.


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[SnowBlaZR2]

You and your wife don’t have the same hemi, transmission, and suspension components either. The diff is more analogous to a longer lever such as you having longer arms than your otherwise identical twin brother.


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If you know what kind of engine, transmission, and suspension my wife has we have bigger problems than your defense of weak gearing.

 

[Johnny_H]

Wait. Is she the Ram and you the Ridgeline? My apologies lol


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[SnowBlaZR2]

Wait. Is she the Ram and you the Ridgeline? My apologies lol


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She's 3.21s and I'm 3.92s, obviously.

 

[Ninety-9 SE-L]

Sure they're conservative, but they're equally conservative. I look at it like this. My wife and I can both lift 50 lbs. If we only do that once a day, and one day a year, big deal. But if we do it 100 times a day, every day of the year, she's going to get tired faster than I am and she's going to wear out before I do. She's just not as strong or big as I am, and it'll eventually show if we do enough work. The 3.21s might pull heavy loads, but they're never going to be as good at moving them as 3.92s.

Now sure, if you press this button, and hold the throttle at that position, and make sure you fart out the sliding glass window instead of the sunroof, the 3.21s can give you similar performance in some situations. Or, just get the right gears from the start and hit the gas pedal when you want to go.

People and machines are not the same. A truck is not going to tire out if it carries a particular weight once or 100 times, assuming the truck isn't overheating or otherwise bending at the frame/suspension components.

The 3.92 only offers the engine a slight mechanical advantage (again, between 0 and 24mph). That 3.92 is not going to make the frame or suspension stronger. It's not going to stop you faster if you have to jam on the brakes. It's not going to save you if a gust of wind hits the side of your trailer. It's not going to balance your load or prevent sway. It gives you a bit better acceleration and maybe a little better at engine braking, too. That 3.92's mechanical advantage WILL certainly help your truck handle a pulling load up and down steep grades, or if you're REALLY pulling a load on a flat surface (like 30,000lbs), it might mean the difference between you actually getting up to a usable speed, at all.

I'm sure people are familiar with the Ford 1,000,000lb pulling stunt:

Pulling 1-million lbs is easier than it looks, I'm sure our trucks could do it too. The problem is it's not practical at any usable speed or on any grade. It's no longer a question of which axle ratio you have.

Bottom line, my truck (with the 3.92) is rated for 9,900lbs of towing capacity, my truck (with the 3.21) is rated for about 8,200lbs of towing capacity. Same exact truck in every single way, same brakes, frame, engine, suspension, hitch, tow assists, etc. In my opinion, I'm probably not going to tow more than 5,000lbs except once in a blue moon...BUT, if I felt like putting 9,900lbs on the back and hitting the highway, I'd probably be comfortable with that, unless I was planning to climb steep hills. In fact, I'd probably be comfortable pulling 15,000lbs at mild speeds and favorable conditions, so long I'm not overloading the GAWR.

In fact, the GAWR and 2X the Tow Rating are the only numbers that I feel are the "Hard Limit" on what what our trucks could do, REGARDLESS of speeds or external road conditions, like even 1000ft up my neighborhood street.

 

[SnowBlaZR2]

People and machines are not the same. A truck is not going to tire out if it carries a particular weight once or 100 times, assuming the truck isn't overheating or otherwise bending at the frame/suspension components.

The 3.92 only offers the engine a slight mechanical advantage (again, between 0 and 24mph). That 3.92 is not going to make the frame or suspension stronger. It's not going to stop you faster if you have to jam on the brakes. It's not going to save you if a gust of wind hits the side of your trailer. It's not going to balance your load or prevent sway. It gives you a bit better acceleration and maybe a little better at engine braking, too. That 3.92's mechanical advantage WILL certainly help your truck handle a pulling load up and down steep grades, or if you're REALLY pulling a load on a flat surface (like 30,000lbs), it might mean the difference between you actually getting up to a usable speed, at all.

I'm sure people are familiar with the Ford 1,000,000lb pulling stunt:

Pulling 1-million lbs is easier than it looks, I'm sure our trucks could do it too. The problem is it's not practical at any usable speed or on any grade. It's no longer a question of which axle ratio you have.

Bottom line, my truck (with the 3.92) is rated for 9,900lbs of towing capacity, my truck (with the 3.21) is rated for about 8,200lbs of towing capacity. Same exact truck in every single way, same brakes, frame, engine, suspension, hitch, tow assists, etc. In my opinion, I'm probably not going to tow more than 5,000lbs except once in a blue moon...BUT, if I felt like putting 9,900lbs on the back and hitting the highway, I'd probably be comfortable with that, unless I was planning to climb steep hills. In fact, I'd probably be comfortable pulling 15,000lbs at mild speeds and favorable conditions, so long I'm not overloading the GAWR.

In fact, the GAWR and 2X the Tow Rating are the only numbers that I feel are the "Hard Limit" on what what our trucks could do, REGARDLESS of speeds or external road conditions, like even 1000ft up my neighborhood street.

Sure, but weight and force are. People also rest, recover, and heal. Machines don't. When you overwork 3.21s and wear them down, they don't bounce back after some protein and a nap.

The biggest thing you're missing is transmission wear.

But hey, if you want to tow over weight, go for it. It isn't my truck or my money.

 

[BowDown]

Sure, but weight and force are. People also rest, recover, and heal. Machines don't. When you overwork 3.21s and wear them down, they don't bounce back after some protein and a nap.

The biggest thing you're missing is transmission wear.

But hey, if you want to tow over weight, go for it. It isn't my truck or my money.

Well using that logic, with a 3.92 truck the engine is always running at 200 to 500 RPM more than a 3.21 truck, 100% of the time.
The 3.21 truck assuming we agree on the wear, would only have increased wear while towing which is nowhere near 100% of the time.

Now, assuming wesr is appreciable on either, which would I rather have to replace due to wear, a rear end a transmission or an engine?

 

[SnowBlaZR2]

Well using that logic, with a 3.92 truck the engine is always running at 200 to 500 RPM more than a 3.21 truck, 100% of the time.
The 3.21 truck assuming we agree on the wear, would only have increased wear while towing which is nowhere near 100% of the time.

Now, assuming wesr is appreciable on either, which would I rather have to replace due to wear, a rear end a transmission or an engine?

Automatic transmissions typically wear out before an engine. Repairing a transmission is also generally more expensive.

Also, the relation in wear between towing and not towing is nowhere near 1:1.

 

[IvoryHemi]

Takes a lot to run an extra 500 rpm....

60 mph: 1649 - 1350 = 299 rpm
65 mph: 1786 - 1463 = 323 rpm
70 mph: 1924 - 1575 = 349 rpm
75 mph: 2061 - 1688 = 373 rpm
80 mph: 2199 - 1800 = 399 rpm
100 mph: 2749 - 2251 = 498 rpm

 

[BowDown]

Automatic transmissions typically wear out before an engine. Repairing a transmission is also generally more expensive.

Also, the relation in wear between towing and not towing is nowhere near 1:1.

Claiming alleged increase wear using a 3.21 gear set over 3.92 is a stretch at best.
You're not going to have a trans failure because of a gear set.

An engine can cost as much as 8K by the time it's in on the cheap side, trans would be $4-5k

5.7 engine from Mopar is $46-4900

Engine Identification, Service Engines & Engine Service Kits for 2021 Ram 1500 | Mopar Online Parts

parts.moparonlineparts.com

Trans is $3300

Transmission Assembly for 2021 Ram 1500 | Mopar Online Parts

parts.moparonlineparts.com

Lot more labor to install r&r and engine vs a trans also

 

[SnowBlaZR2]

And claiming alleged increase wear using a 3.21 gear set over 3.92 is a stretch at best.
You're not going to have a trans failure because of a gear set.

I think you ought to stick to making claims about your 5200 lb truck...

 

[mikeru82]

Claiming alleged increase wear using a 3.21 gear set over 3.92 is a stretch at best.
You're not going to have a trans failure because of a gear set.

An engine can cost as much as 8K by the time it's in on the cheap side, trans would be $4-5k

5.7 engine from Mopar is $46-4900

Engine Identification, Service Engines & Engine Service Kits for 2021 Ram 1500 | Mopar Online Parts

parts.moparonlineparts.com

Trans is $3300

Transmission Assembly for 2021 Ram 1500 | Mopar Online Parts

parts.moparonlineparts.com

Lot more labor to install r&r and engine vs a trans also

Stop poking the teddy bear.

 

[SnowBlaZR2]

Stop poking the teddy bear.

We're good. This is a dude who thought his truck weighed something like 500-700 lbs less than everyone else's.

 

[Idahoktm]

Well using that logic, with a 3.92 truck the engine is always running at 200 to 500 RPM more than a 3.21 truck, 100% of the time.

Only if you drove on the freeway 100% of the time. Driving around town, the difference in rpm's is insignificant.