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

[Hasti17]

Yet here you are with your "2 cents"

 

[Whoa_Ram]

I should have just bought a damn 2500 then..

 

[theblet]

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.

That’s my thinking behind it. Not towing so I’d rather just save a little cash on the highway. But if the truck I wanted had 3.92s, I woulda bought that instead.

there’s no correct answers in this thread. Just opinions.

 

[KWKSLVR]

I'll take the cash too. The way I drive that some sweet new hunting gear every year. $500 is $500. Maybe that mentality is why I can pay cash for my truck....

 

[BowDown]

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.

If I were towing heavy with any consistency, I'd buy a 2500

 

[silver billet]

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.

Using your numbers: 1800/year * 10 years = $18,000 over a reguarly average lifetime.

Moses, you guy's have blinders on don't you?

 

[silver billet]

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?

I didn't miss your point; you're simply using a logical fallacy to try to prove your point. What's next, proving the 3.21 is useless because I wouldn't want to tow with a 1.3??? Well, then I guess the 3.92 is a very poor choice because you wouldn't want to drive a 7.9.

You can't make arguments like that. We don't have a 2.62. I haven't done the math to see whether my truck with a 2.62 is viable.

I HAVE done the math on my truck, and the 3.92, and compared it other trucks that actually exist; like the Tundra with a 4.30. The 3.21 is a very capable tow rig compared to other trucks that exist, and there is no need to jump up to a higher gear ratio except for some very very slim cases.

 

[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.

You didn't have to reply. That was your choice. Was no dragging involved.

As for your last two paragraphs, all theoretical. And still not enough of a "savings" to be bragging/arguing about. Crunch the numbers and it's a small difference in fuel cost when spread out long term.

 

[HSKR R/T]

Using your numbers: 1800/year * 10 years = $18,000 over a reguarly average lifetime.

Moses, you guy's have blinders on don't you?

And with 3.21 you are $15600. Less than $3000 difference over 10 years. People waste more money than that on coffee or energy drinks.

 

[HSKR R/T]

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?

Where did you get your numbers from? I doubt anyone is getting 17-18mpg in city driving. Right now, I'm averaging about 15-16mpg displayed mileage in "city" driving.

As for your blanket statement about people complaining in every other thread about fuel mileage, most don't specify what gears they have in most threads. And anyone complaining about gas mileage in a V8 powered 1/2 ton truck probably shouldn't be driving a truck.

 

[silver billet]

And with 3.21 you are $15600. Less than $3000 difference over 10 years. People waste more money than that on coffee or energy drinks.

I'm glad you mentioned the word "waste" lol, because that's exactly what you're doing with the 3.92. Ergo, blinders.

Let's use my exact numbers, we have some conversions to Liters because I'm in Canada.

15,500 miles/year, roughly 18 mpg, 89 octane at 1.50/L.
I use 861 gallons = 3259 liters
3259 liters at $1.50 = 4888/year

Now do the same for 15 mpg, I would use 1033 gallons = 3910 liters
3910 liters at $1.50 = 5865/year

Difference = $977, * 10 years = 9800.

For fun, also remember the price of gas is going to climb (considerably) the next 10 years. 10 years from now gas prices are probably 1.85 to 2.00/L, which I have not accounted for at all in this. So $10,000 is very conservative, count on closer to $12,000.

So you think adding $10,000 to the purchase price of $45,000, for no advantage, is ... at all sane?

Just send me the cheque, I did not get to my position in life affording this truck by just pi$$ing away $10,000, but maybe you didn't have to work for your money.

 

[silver billet]

And anyone complaining about gas mileage in a V8 powered 1/2 ton truck probably shouldn't be driving a truck.

You're truly deluded. I guess I'll pull my 7000 pound trailer behind my prius.

 

[silver billet]

As for your last two paragraphs, all theoretical.

Of course you say it's theoretical, you're one of these "facts are optional" guys.

 

[HSKR R/T]

I'm glad you mentioned the word "waste" lol, because that's exactly what you're doing with the 3.92. Ergo, blinders.

Let's use my exact numbers, we have some conversions to Liters because I'm in Canada.

15,500 miles/year, roughly 18 mpg, 89 octane at 1.50/L.
I use 861 gallons = 3259 liters
3259 liters at $1.50 = 4888/year

Now do the same for 15 mpg, I would use 1033 gallons = 3910 liters
3910 liters at $1.50 = 5865/year

Difference = $977, * 10 years = 9800.

For fun, also remember the price of gas is going to climb (considerably) the next 10 years. 10 years from now gas prices are probably 1.85 to 2.00/L, which I have not accounted for at all in this. So $10,000 is very conservative, count on closer to $12,000.

So you think adding $10,000 to the purchase price of $45,000, for no advantage, is ... at all sane?

Just send me the cheque, I did not get to my position in life affording this truck by just pi$$ing away $10,000, but maybe you didn't have to work for your money.

Still theoretical numbers. You are assuming a lot without any factual data to support it as far as average fuel mileage. Also, every owner will be different due to different driving habits. One can not "factually" make up numbers to support ones argument and claim to be correct. Without comparing two equally optioned trucks, other than hearing, side by side under the same conditions, anything being discussed here is theoretical, or "best guess". You can try to engineer your way out of it based on RPM and EPA estimates of fuel mileage, but we all know how BS the EPA estimates are.

 

[Mountain Whiskey]

How many threads are there with 3:92 guys crying about fuel mileage?

Just about as many as there are 3:21 guys claiming they get better milage than a Prius.

3:92 guys understand they are driving a truck and not an econobox. They understand that trucks are heavy machines. They understand that truck tires are heavy. They know that these heavy trucks with oversized heavy duty tires require power to propel them and that uses fuel. They realize that lifts can be useful for fun times and sometimes just cool. They also know that this requires fuel consumption.

3:92 guys have this knowledge and are proud to not be a neckbeard in a Prius. But there is something we don't understand. We know that this phenomena exists out there but it is outside of our comprehension. 3:21 guys would be the ideal ones to explain it to us since they would be most familiar with the condition. What's it like to go through life with a miniature winkie? I mean really, it must be tough when she says "Oh, no thanks, I don't smoke".

 

[theblet]

I didn’t know I was a 3.21 guy I just like my truck and drive it

 

[Mountain Whiskey]

I didn’t know I was a 3.21 guy I just like my truck and drive it

Shhh. Don't tell anyone. Just let them think you drive slow on purpose.

 

[lkjk]

Using your numbers: 1800/year * 10 years = $18,000 over a reguarly average lifetime.

Moses, you guy's have blinders on don't you?

Yep, vs $15,650, which is only $2,350 difference. Over 10 years, who cares.

Consider this: you make $75K/year. Maybe you take home 65%. That's 487,500 over 10 years. $2,350 is 0.48% of that. This ignores time value of money and annual pay increases, so technically that 487,500 is low.

Honestly, if you're worried about that small of a difference over a 10 year period, you have no business buying a 30K plus whatever vehicle. the difference is minute (and proved above, so idk why you keep fighting it), and honestly not worth mentioning unless $20/mo will make or break you, which again means you shouldn't be buying the truck in the first place.

 

[theblet]

Even if it won’t break you, to some people $20 is $20. Take what you can get in this economy.

 

[KWKSLVR]

Shhh. Don't tell anyone. Just let them think you drive slow on purpose.

You're driving a truck. The only mode it has is slow.