Remembered why I got a F450 with 4.30 gears ... observation.

[jimh406]

During the past few days, I drove my daughter's families stuff up from El Paso in a 36 ft Penske truck. We were 23,400 according to the Cat Scale. We made it ... a little brutally slow at times. We chose the the pretty route up through NM, UT, ID, OR, and then WA.

A lot of it was nearly the same as we took earlier this year, but we were going as slow as 45 mph up some of the steep mountains. My DW made the comment that the mountains didn't seem so steep in our TC! Obviously we were slow down the mountains as well with not nearly as good as brakes as my F450 with the TC loaded.

I don't know what model engine it had, but it did have a regen mode. It also was an International chassis, so I guess some Navistar model. It was also a pretty bouncy ride and pretty loud compared to the plush F450 Lariat.

It was a strange feeling to be the guy who was going a mile or two mph faster up a hill to pass. A few times, I passed semis that were going probably 35 mph over the past few days, so I guess it could be worse. I did have to look way down the mountain to see if it was possible to attempt the pass. I pass whenever I want with the F450.

Any way, I'm really happy to have the best tool for the job of going up our mountains, and so happy with the choice!

[jimh406]

Kayteg1 wrote:
We are comparing here gearing effect at highway speeds.

Maybe, you should read this article. Here's a quote from it that you seem to not understand.

How to Pick Pickup Truck Axle Gear Ratios to Improve Performance


Higher numerical ratios often increase fuel consumption. "The penalty in fuel economy varies because it depends so much on your use," says Slevin. "If you drive it with low loads, you will see a fuel economy decrease with a higher numerical axle ratio, particularly at highway speeds. If you are driving loaded a lot of the time, there is a point where fuel economy crosses over and is equivalent or even better." If you are driving in a city environment at slower speeds, you may also see a fuel economy increase with a higher numeric axle ratio.

General Motors compares its L96 gas engine paired with a 3.73 or 4.10 axle ratio. "If you look at your base vehicle at curb or lightly loaded, and you go from a 3.73 to a 4.10 final drive ratio, you will see a .2- to .3-mpg reduction on the highway at highway speeds during normal driving (unloaded)," says Martuch. "Hook a large trailer to it and start pulling grades, and you are going to see a .3- or even a .5- mpg reduction in fuel economy with a 3.73 because you are running so much higher rpms pulling the grades."

Ford offers its 6.2-liter gasoline engine with a 3.73 or a 4.30 axle ratio. "For anyone who will tow or do something with a heavy load the majority of the time, we have noticed that with a 10,000-lb. trailer, the fuel economy is significantly better -- in the mile-plus range -- when towing with the 4.30," states Tim Ogilvie, fuel economy engineer.

"The physics behind that is, with the 4.30 axle ratio, you're in sixth gear more of the time," Slevin explains. "With the lower numerical ratio, you are more likely to be in fifth or fourth."

Many dedicated commercial trucks do not offer a choice of axle ratios. For example, the Ford F-450 and F-350 DRW pickups only come with one gear ratio. "We have the one ratio because we suspect those trucks are primarily being used for a commercial-type application where they are all heavily loaded," says Slevin.

[Tom_Anderson]

First, can we clarify what we mean by low gears? 4.30 gears are lower than 3.73s (even though they are numerically higher). I think there might be some confusion there.

[Kayteg1]

Tom_Anderson wrote:


If you mean higher numerical gearing, you're correct. It won't give you more horsepower. But it will help keep the engine in the RPM range where it makes the most power, and it certainly helps get a heavy load moving from a standstill.

We are comparing here gearing effect at highway speeds.
My manual 6-sp had LOW gear below 1st and that could haul a house at idle for sure.
The F250 auto with lower differential gearing made me couple of times switching to Low on transfer case, but low transmission gearing and differential gearing are different animals.

[Tom_Anderson]

Kayteg1 wrote:
Higher gearing is not giving you more power. More convenience yes, but at cost.

If you mean higher numerical gearing, you're correct. It won't give you more horsepower. But it will help keep the engine in the RPM range where it makes the most power, and it certainly helps get a heavy load moving from a standstill.

[jimh406]

Kayteg1 wrote:
Higher gearing is not giving you more power.

The manufacturer ratings and probably almost everyone here will disagree with you.

[Kayteg1]

Higher gearing is not giving you more power. More convenience yes, but at cost.
Try to drive your truck for one tank with overdrive disabled, so you will see your own experience.

[jimh406]

Kayteg1 wrote:
So the only big factor for over 30 percent different mpg was gearing.

Obviously, there's no way 30% was the gearing factor at anywhere close to reasonable highway speeds. Almost everything about the F450 other than the body and bed was different and heavier.

At the end of the day, that doesn't matter though. If you want to optimize for unloaded driving and mpg, go for it. That's not a reasonable tradeoff for many of us who would rather optimize for the loaded case with power going over mountains.

[Kayteg1]

The fuel savings will obviously depends on the mileage you put every year.
As I wrote above, the difference in mpg on my trucks was huge.
Both had the same engine, both were flatbeds, one was dually, other 4WD what makes them about equal in rolling resistance.
So the only big factor for over 30 percent different mpg was gearing.

[Tom_Anderson]

Kayteg1 wrote:

jimh425 wrote:

Kayteg1 wrote:
I used to own small pickups that require downshifting with head wind, so I know what over or undergearing is.

Me, too, but my S-10 was a V6 with a 3.73 gears. 🙂 No doubt you know what overgearing is to you, but we don't all have the same expectations on what gearing is best.

I spend most of my life driving manuals and for me overdrive is just what it says - over.
Should be only for no load, no front wind applications.
When there is a load, I never had a problem driving on lower gear. That is what semi-drivers do all the time.
On other hand spending big hundreds on fuel burn unnecessary due to overgearing never made sense to me.
So ask yourself a question - is spending $2000 every year on fuel only to avoid few downshifting something what you expect?
How about $1000 or only $500?

There is no way I pay nearly that much more for fuel because I have 4.30 gears. And if I did, it would be totally be worth it for the extra performance and all-around driveability. The 4.30 gears should be standard, IMO, with 3.73 being an option for people who don't haul or tow heavy loads. I don't know anybody who buys a Super-Duty for mileage.

[Kayteg1]

jimh425 wrote:

Kayteg1 wrote:
I used to own small pickups that require downshifting with head wind, so I know what over or undergearing is.

Me, too, but my S-10 was a V6 with a 3.73 gears. 🙂 No doubt you know what overgearing is to you, but we don't all have the same expectations on what gearing is best.

I spend most of my life driving manuals and for me overdrive is just what it says - over.
Should be only for no load, no front wind applications.
When there is a load, I never had a problem driving on lower gear. That is what semi-drivers do all the time.
On other hand spending big hundreds on fuel burn unnecessary due to overgearing never made sense to me.
So ask yourself a question - is spending $2000 every year on fuel only to avoid few downshifting something what you expect?
How about $1000 or only $500?

[jimh406]

Kayteg1 wrote:
I used to own small pickups that require downshifting with head wind, so I know what over or undergearing is.

Me, too, but my S-10 was a V6 with a 3.73 gears. 🙂 No doubt you know what overgearing is to you, but we don't all have the same expectations on what gearing is best.

[Kayteg1]

My F450 unloaded barely made 10 mpg, F250 was making 14 easy, reaching 16 and i did not drive F450 faster than 65 mph as above the mpg was taking nose-dive.
450 was DRW, 250 was 4WD
Measuring mpg while hauling 18k in my case was not reliable, as most of the trips were in 100 miles range, so not full tank.
Still F250 had gearing to pull 18k trailer at freeway speeds on overdrive.
I used to own small pickups that require downshifting with head wind, so I know what over or undergearing is.

[jimh406]

Kayteg1 wrote:
Years ago I switched from F450 to F250 and F250 pulled the 18,000lb trailer just fine (same 7.3l engine on both) while delivering way better mpg.
Pickups are over-geared from the factory IMHO and what is nice on passing, is always biting you at fuel pump.

Based on my research with lots of owners posts who pull large trailers, there is barely any difference in mpg under a heavy load due to gearing and in some cases, higher gearing can actually perform better until the speed goes pretty high because the effective rpm is essentially the same. Only the gear changes. If we are talking about flat land and light loads that goes out the window.

I am wondering what you are calling "way better mpg".

I think many people think the biggest impact on mpg for TCs is DRW vs SRW. Of course, we have empirical data because essentially nobody has every model of truck with every size load and with every terrain. 🙂

[Kayteg1]

Nautique200 wrote:
I love my F450. Its a pulling machine. 26K and it never complains. I've removed some stuff and tuned it, the power it has is incredible.

Years ago I switched from F450 to F250 and F250 pulled the 18,000lb trailer just fine (same 7.3l engine on both) while delivering way better mpg.
Pickups are over-geared from the factory IMHO and what is nice on passing, is always biting you at fuel pump.

[Tom_Anderson]

An F-450 wasn't in the budget when I bought my truck, so I'll just wave to you guys as you pass me going up the mountains in my V-10 powered F-250 (with 4.30 gears, at least). You might beat me, but I'll still get there. :B