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

[silver billet]

And those preaching about gas mileage in a 1/2 ton truck don't realize the minute difference doesn't make that big of a difference long term. Basically just bragging rights. And most of those guys are probably also cheaping out running 87 octane instead of the recommended 89.

Stop dragging me back into this thread please. It has nothing to do with bragging rights, nobody goes around bragging about their fuel mileage, we leave the bragging to the 3.92 guys.

Lets do the math; a 3 mpg difference from 20 to 23 mpg is a difference of 13%. "minute" huh? I don't brag that I save anywhere from 10 to 20 percent on my fuel bill, but I sure as heck don't try to cover it up either.

Some of y'all need to read a math/physics textbox or something because you have your "minute" and "significant" factors completely backwards.

The amount of time/hours my truck spends in 8th gear? Huge. Like at least 95% of the lifetime hours on my truck is in 8th gear if we ignore reverse/idle/park. Others may be slightly less, but still. 95% of the lifetime of my truck I benefit from the 3.21

Now lets add up the amount of time I'm A) pulling a trailer > 6000 pounds, and B) using first and/or second gear where the differences in our truck are most significant... it's literally < 15 minutes in the lifetime of my truck so far and that's being very generous.

Think hard about those last 2 paragraphs and tell me I'm the stupid one. And FYI, I refuse to run 87. 89 unloaded, 91 when pulling.

 

[theblet]

You have to tow a 7,500lb trailer over the Rockies.
You have two Ram 1500's at home with the same 5.7 Hemi engine and transmissions.
One has a 3.21 rear and the other has a unique 2.62 rear.
Which one are you going to use to tow that trailer over the Rockies?

The one with Apple car play and heated seats.

 

[HSKR R/T]

You think 17-18 in the city vs 14-15 in the city is a minute difference?

I get better than 14-15 in the city with my 3.92, and if I drove a 3.21 the same as I drive my 3.92 there wouldn't be much difference.

 

[silver billet]

You have to tow a 7,500lb trailer over the Rockies.
You have two Ram 1500's at home with the same 5.7 Hemi engine and transmissions.
One has a 3.21 rear and the other has a unique 2.62 rear.
Which one are you going to use to tow that trailer over the Rockies?

I don't have 2 trucks at home. I can afford one, and it needs to have compromises somewhere because every truck is a compromise. So I buy the truck that makes the most sense, and that is a 5th gen with a 3.21. It will pull up the rockies just fine, we've seen TFL Truck test these trucks on the Ike guantlett etc and they perform great.

The 2.62 is a strawman argument. We have 8 speeds with a 3.21. First gear is so short with this setup, it's still shorter than a Toyota Tundra 6 speed with a 4.30. Think about that. I suggest you go up to every Tundra guy and tell him his truck won't pull 8000 pounds up the rockies, see how often you get laughed at. And yet our 3.21's have even more bottom end. Hmm... Makes you think don't it?

 

[HSKR R/T]

Stop dragging me back into this thread please. It has nothing to do with bragging rights, nobody goes around bragging about their fuel mileage, we leave the bragging to the 3.92 guys.

Lets do the math; a 3 mpg difference from 20 to 23 mpg is a difference of 13%. "minute" huh? I don't brag that I save anywhere from 10 to 20 percent on my fuel bill, but I sure as heck don't try to cover it up either.

Some of y'all need to read a math/physics textbox or something because you have your "minute" and "significant" factors completely backwards.

The amount of time/hours my truck spends in 8th gear? Huge. Like at least 95% of the lifetime hours on my truck is in 8th gear if we ignore reverse/idle/park. Others may be slightly less, but still. 95% of the lifetime of my truck I benefit from the 3.21

Now lets add up the amount of time I'm A) pulling a trailer > 6000 pounds, and B) using first and/or second gear where the differences in our truck are most significant... it's literally < 15 minutes in the lifetime of my truck so far and that's being very generous.

Think hard about those last 2 paragraphs and tell me I'm the stupid one. And FYI, I refuse to run 87. 89 unloaded, 91 when pulling.

Didn't "drag" anyone back into this. You felt the need to flex your 3.21 superiority complex. You weren't dragged in.

 

[silver billet]

I get better than 14-15 in the city with my 3.92, and if I drove a 3.21 the same as I drive my 3.92 there wouldn't be much difference.

There is no difference in MPG in the city. You need to put the 3.21 into 8th gear before you see any MPG differences.

 

[silver billet]

Didn't "drag" anyone back into this. You felt the need to flex your 3.21 superiority complex. You weren't dragged in.

You replied to me. I was going to stay out yesterday but you ended up replying (to me) so here I am again.

 

[lkjk]

Lets do the math; a 3 mpg difference from 20 to 23 mpg is a difference of 13%. "minute" huh? I don't brag that I save anywhere from 10 to 20 percent on my fuel bill, but I sure as heck don't try to cover it up either.

Some of y'all need to read a math/physics textbox or something because you have your "minute" and "significant" factors completely backwards.

At 20mpgs, 12,000 miles per year, you burn 600 gallons of fuel. At $3/gallon, that equates to $1,800/year on gas. At 23mpgs, you burn 522 gallons, which is $1,565 per year, a savings of $235, or $19.57 per month. At $3.50/gallon, the savings only jumps to $274/year or $22.83/mo.

I don't see those mpg numbers, but my point is financially it's really not a huge difference. Saying "i save 10-20% on my fuel bill" sounds like a lot, but when you do the math, yes, it is minute.

 

[KWKSLVR]

You guys only drive 12000 miles/year? Dang. I do like 20-30K

 

[lkjk]

I was just going by "standard" at 30K miles a year and $3/gallon, its still only a $587 difference in gas per year. Adds up if you drive a lot but still less than you'd think

 

[Buz]

I don't have 2 trucks at home. I can afford one, and it needs to have compromises somewhere because every truck is a compromise. So I buy the truck that makes the most sense, and that is a 5th gen with a 3.21. It will pull up the rockies just fine, we've seen TFL Truck test these trucks on the Ike guantlett etc and they perform great.

The 2.62 is a strawman argument. We have 8 speeds with a 3.21. First gear is so short with this setup, it's still shorter than a Toyota Tundra 6 speed with a 4.30. Think about that. I suggest you go up to every Tundra guy and tell him his truck won't pull 8000 pounds up the rockies, see how often you get laughed at. And yet our 3.21's have even more bottom end. Hmm... Makes you think don't it?

You missed my point.

 

[BowDown]

You have to tow a 7,500lb trailer over the Rockies.
You have two Ram 1500's at home with the same 5.7 Hemi engine and transmissions.
One has a 3.21 rear and the other has a unique 2.62 rear.
Which one are you going to use to tow that trailer over the Rockies?

What ram can you get with a 2:62 rear?

 

[BowDown]

I get better than 14-15 in the city with my 3.92, and if I drove a 3.21 the same as I drive my 3.92 there wouldn't be much difference.

Yet you didn't specify what you get.
How many threads are there with 3:92 guys crying about fuel mileage? Not sure why in this thread 3:92's get great or similar fuel mileage yet in every other thread, its those same 3:92 people complaining about fuel mileage and proclaiming that somethings wrong with the truck. Which is it?

 

[BowDown]

I don't have 2 trucks at home. I can afford one, and it needs to have compromises somewhere because every truck is a compromise. So I buy the truck that makes the most sense, and that is a 5th gen with a 3.21. It will pull up the rockies just fine, we've seen TFL Truck test these trucks on the Ike guantlett etc and they perform great.

The 2.62 is a strawman argument. We have 8 speeds with a 3.21. First gear is so short with this setup, it's still shorter than a Toyota Tundra 6 speed with a 4.30. Think about that. I suggest you go up to every Tundra guy and tell him his truck won't pull 8000 pounds up the rockies, see how often you get laughed at. And yet our 3.21's have even more bottom end. Hmm... Makes you think don't it?

Exactly

How was this truck equipped again and what most popular truck and engine combo did it win against?
Seems like a capable truck to me

 

[Buz]

I don't have 2 trucks at home. I can afford one, and it needs to have compromises somewhere because every truck is a compromise. So I buy the truck that makes the most sense, and that is a 5th gen with a 3.21. It will pull up the rockies just fine, we've seen TFL Truck test these trucks on the Ike guantlett etc and they perform great.

The 2.62 is a strawman argument. We have 8 speeds with a 3.21. First gear is so short with this setup, it's still shorter than a Toyota Tundra 6 speed with a 4.30. Think about that. I suggest you go up to every Tundra guy and tell him his truck won't pull 8000 pounds up the rockies, see how often you get laughed at. And yet our 3.21's have even more bottom end. Hmm... Makes you think don't it?

What ram can you get with a 2:62 rear?

You both missed my point.
Open your mind and pretend a 2.62 rear does exist on our trucks.

Seems the 3.21 guys just don't get the point of this post:
You have to tow a 7,500lb trailer over the Rockies.
You have two Ram 1500's at home with the same 5.7 Hemi engine and transmissions.
One has a 3.21 rear and the other has a unique 2.62 rear.
Which one are you going to use to tow that trailer over the Rockies?

 

[BowDown]

You guys only drive 12000 miles/year? Dang. I do like 20-30K

Yeah, I'm at 25K, trucks 14 months old

 

[BowDown]

You both missed my point.
Open your mind and pretend a 2.62 rear does exist on our trucks.

Seems the 3.21 guys just don't get the point of this post:
You have to tow a 7,500lb trailer over the Rockies.
You have two Ram 1500's at home with the same 5.7 Hemi engine and transmissions.
One has a 3.21 rear and the other has a unique 2.62 rear.
Which one are you going to use to tow that trailer over the Rockies?

No, theres no validity to the question as its not available
Second, that would be a poor configuration gear wise as the truck doesn't make enough torque/power down low and too much weight to effectively turn that gear.
The same question asked another way is which is
You have to tow a 7,500lb trailer over the Rockies.
You have two Ram 1500's at home with the same 5.7 Hemi engine and transmissions.
One has a 3.92 rear and the other has a unique 4:88 rear.
Which one are you going to use to tow that trailer over the Rockies?

But to answer your question, the 2:62 truck could simply only use gears 1-4 and tow fine, now in my scenario, you only have 8 gears, trucks gonna be screaming with 4:88's.
The 2:62 truck would struggle more from a standing start but thats a moot point as that combo isn't available.
I get the point you're trying to make but your flaw is that the 3:21 truck would simply be one gear lower than the 3:92 truck. IE. 3:92 in 5th, 3:21 in 4th and 2:62 truck in 2nd possibly 3rd

 

[Hasti17]

you all are lucky... you must have wives that LOVE talking about how BIG and AMAZING your "Gears" are...


That's the only way id have the willpower to argue whos got the SUPER-BEST gears for months on end.

anyway, back to the debate folks.

And don't worry, If anyone is mean to you on this thread it prolly cause they're shy and really like your "gears"

 

[BowDown]

you all are lucky... you must have wives that LOVE talking about how BIG and AMAZING your "Gears" are...


That's the only way id have the willpower to argue whos got the SUPER-BEST gears for months on end.

anyway, back to the debate folks.

And don't worry, If anyone is mean to you on this thread it prolly cause they're shy and really like your "gears"

Yet here you are with your "2 cents"

 

[Buz]

I get the point you're trying to make but your flaw is that the 3:21 truck would simply be one gear lower than the 3:92 truck. IE. 3:92 in 5th, 3:21 in 4th and 2:62 truck in 2nd possibly 3rd

The point I'm making is simply that the 3.92 is better if you bought the truck to tow heavy. And that the 3.21 is better if you bought the truck without heavy towing in your plans.
Look, I have a 3.92 and do not tow with my truck. I'm pretty sure if I drove a 3.21 I'd much rather have that. So my posts aren't biased toward the 3.92 just because I have one.