3.21. vs 3.92 gear

[theblet]

So can the claim that 3.21s are better for fuel economy.

It's better for fuel economy if you do a lot of highway driving and don't tow too much.

 

[HSKR R/T]

It's better for fuel economy if you do a lot of highway driving and don't tow too much.

When you have to add disclaimers is it really that beneficial?

 

[petersandler]

So can the claim that 3.21s are better for fuel economy.

Actually, the math and science are pretty much indisputable that 3.21's get better highway mileage. There are literally hundreds of websites that validate this. However, this description probably sums up the issue the best.

"While the gear ratio will have an effect on the actual fuel economy of your vehicle, your driving habits will offset any gains or losses....At less than 60 miles per hour, fuel economy is primarily dependent on driver habits, rather than gear ratio....The gear ratio is not only affected by the axle, but also the tire size. If your vehicle has a low gear ratio, you can offset this by installing slightly larger diameter tires. For example, a vehicle with a 4.10 axle with 30.2 inch diameter tires will have a new gear ratio of 3.97 with 31.2 inch diameter tires installed...At a given speed, and if all else is equivalent, a higher gear ratio axle -- again, a lower number -- will have a positive effect on fuel economy. The effect is generally minimal and will account for less than a single mile per gallon, and typically the gains are generally seen at highway speeds."

 

[HSKR R/T]

Actually, the math and science are pretty much indisputable that 3.21's get better highway mileage. There are literally hundreds of websites that validate this. However, this description probably sums up the issue the best.

"While the gear ratio will have an effect on the actual fuel economy of your vehicle, your driving habits will offset any gains or losses....At less than 60 miles per hour, fuel economy is primarily dependent on driver habits, rather than gear ratio....The gear ratio is not only affected by the axle, but also the tire size. If your vehicle has a low gear ratio, you can offset this by installing slightly larger diameter tires. For example, a vehicle with a 4.10 axle with 30.2 inch diameter tires will have a new gear ratio of 3.97 with 31.2 inch diameter tires installed...At a given speed, and if all else is equivalent, a higher gear ratio axle -- again, a lower number -- will have a positive effect on fuel economy. The effect is generally minimal and will account for less than a single mile per gallon, and typically the gains are generally seen at highway speeds."

Theoretically just based on final drive ratios alone the 3.21 should have an advantage. But there are way more other variables that come into play than gear ratio alone. Even beyond just the driver. One cannot state that one gear ratio is "better" than the other by only using the final drive numbers for each gear. This is what was lost in the OP of this thread. Engineers look at numbers, but generally miss the mark when it comes to real world.

 

[theblet]

When you have to add disclaimers is it really that beneficial?

Idk. But I’ll take all the help I can get with mpg. I based my decision off of how I use my truck. Although if a 3.92 would have shown up for a great price I would’ve taken that instead. I really didn’t want etorque so that was a major factor for me.

 

[SnowBlaZR2]

It's better for fuel economy if you do a lot of highway driving and don't tow too much.

So is a Toyota Camry.

 

[SnowBlaZR2]

Actually, the math and science are pretty much indisputable that 3.21's get better highway mileage. There are literally hundreds of websites that validate this.

Your right foot has an exponentially higher effect on fuel economy than 3.21 vs 3.92 gearing. If you don't know that, you don't know anything.

 

[theblet]

So is a Toyota Camry.

What kinda truck is that?

 

[Dewey]

Your right foot has an exponentially higher effect on fuel economy than 3.21 vs 3.92 gearing. If you don't know that, you don't know anything.

See we can agree on something.

One thing for sure is I’ll never be a “Fuel Economy Champion”. I like the gas pedal WAY too much.

Like the old commercials say…….

 

[theblet]

I’m getting deja vu from the other thread. Guess we’ll be at 2000 posts soon

 

[petersandler]

Your right foot has an exponentially higher effect on fuel economy than 3.21 vs 3.92 gearing. If you don't know that, you don't know anything.

Apparently you failed to read my entire post.

 

[ferraiolo1]

He cherry picks things. Kinda how he cherry pics absurdly high readings off his silly economy trophy screen.

Still <3 ya


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[petersandler]

Theoretically just based on final drive ratios alone the 3.21 should have an advantage. But there are way more other variables that come into play than gear ratio alone. Even beyond just the driver. One cannot state that one gear ratio is "better" than the other by only using the final drive numbers for each gear. This is what was lost in the OP of this thread. Engineers look at numbers, but generally miss the mark when it comes to real world.

I think the second part of my post put the real world perspective on it. Unfortunately, nobody seems to have read beyond the opening because they had their fragile 3.92 gear ratio egos hurt.

 

[HSKR R/T]

I think the second part of my post put the real world perspective on it. Unfortunately, nobody seems to have read beyond the opening because they had their fragile 3.92 gear ratio egos hurt.

I read the whole thing, I just used less words. And the second part of your post where it mentions getting better fuel mileage from larger tires is not accurate because taller tires generally weigh more requiring more HP to turn them negating most of any gains they may have offered with better final drive ratios.

 

[theblet]

I read the whole thing, I just used less words. And the second part of your post where it mentions getting better fuel mileage from larger tires is not accurate because taller tires generally weigh more requiring more HP to turn them negating most of any gains they may have offered with better final drive ratios.

Depends how much larger and the weight/ply rating. All things being equal 3.21 will have the advantage on the highway.

 

[SnowBlaZR2]

What kinda truck is that?

Plenty for the 3.21 crowd.

 

[SnowBlaZR2]

See we can agree on something.

One thing for sure is I’ll never be a “Fuel Economy Champion”. I like the gas pedal WAY too much.

Like the old commercials say…….

Then you should've went with a truck that could get out of its own way.

 

[SnowBlaZR2]

Apparently you failed to read my entire post.

I focused on your post, not what you copied. And what you posted is incorrect.

 

[SnowBlaZR2]

He cherry picks things. Kinda how he cherry pics absurdly high readings off his silly economy trophy screen.

Still <3 ya


Sent from my iPhone using Tapatalk

All I've done is show that the ridiculous claims that 3.21s are better on gas are BS.

 

[SnowBlaZR2]

I think the second part of my post put the real world perspective on it. Unfortunately, nobody seems to have read beyond the opening because they had their fragile 3.92 gear ratio egos hurt.

When I read "math and science" and "indisputable" followed by a lack of either...well, you get what you get.