burningman wrote:
I really don't understand why it's taken forever for the manufactures to build transmissions with a wider overall ratio spread so we don't have this problem.
With my Gear Vendors overdrive, I always have my choice of 4.10 or 3.20. I love both in their own appropriate situations and would hate either if stuck with it all the time.
You'd think they would build 7 or 8 speed transmissions that gave you all the ranges you need.
They give us more than anyone has a right to expect from a pickup truck in just about every other way.
We have 7sp auto in our 2008 sedan, so give pickups another 20 years and they will catch up with technology. :B
I think the main point is that customers don't make demand for fuel-saving features on pickups.
I am shopping around for new F350 dually and such thing like shorter cab, RWD or 3.73 differential simply don't exist on dealers lots, but all trucks do have sunroofs. :S
We have sunroofs on our cars and open them only once a year, at New Year eve while cruising Las Vegas Strip.
I have to build my pickup on the net and wait 2 months to have what I like.
jimh425 wrote:Kayteg1 wrote:
So where is the fuel saving coming from? Thin air?
We've probably beat this one to death ...
You are assuming that the vehicles compared would be able to do the same speed with the same RPM. That's ok, but means that you also have to agree that 3.73s don't have any advantage in mpg over 4.30s in the level ground case.
We've beaten that to death, but it is still not going far.
As I wrote in comparison between my 2 trucks, the one with lower numerical gearing was giving me abut 30 percent better mpg as it was still was able to pull 18,000 lb on overdrive. (not perfectly comparable trucks, so there is margin for error)
The only technical advantage of 4.30 gearing is starting with heavy trailer on 25 percent grade. The rest is just sacrificing fuel consumption for slightly more convenience of taking big grades without downshifting.
Would you have clear disclosure like
"by few downshiftings you do on the truck with different gearing you are saving $50 each time you refuel"
would you still buy it?
jimh425 wrote: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.
I hope you did notice how much BS that quote is giving.
Like " 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,"
Well design transmission on 6th gear and 4.30 differential should give you +- the same gearing what 3.73 differential and 5 th.
So where is the fuel saving coming from? Thin air?
You have lot of factors in vehicle economy, so you don't have "one shoe fits all" situation here.
Each vehicle is having its "sweet spot" and for example where my Ford Truck makes huge mpg at 40 mph, my Mercedes at this speed becomes gas guzzler as it makes way better mpg at 60 mph.
(I can find a speed where 8000 lb diesel pickup and 3500 lb gasoline car will make exactly the same mpg. )
As I mention, low numerical gearing will always give you best mpg, but with the cost of lesser convenience of more gear shifting, so it is always about sacrificing one feature for other.
Than if your transmission gives you 2000 rpm between the highest gear and one below, that sure brings additional issues.
Electric vehicles don't have those problems, so let's wait for electric pickups.
Each vehicle is having its "sweet spot" and for example where my Ford Truck makes huge mpg at 40 mph, my Mercedes at this speed becomes gas guzzler as it makes way better mpg at 60 mph.
(I can find a speed where 8000 lb diesel pickup and 3500 lb gasoline car will make exactly the same mpg. )
As I mention, low numerical gearing will always give you best mpg, but with the cost of lesser convenience of more gear shifting, so it is always about sacrificing one feature for other.
Than if your transmission gives you 2000 rpm between the highest gear and one below, that sure brings additional issues.
Electric vehicles don't have those problems, so let's wait for electric pickups.
Just my experience with gearing....below is my 2007 E350. V-10, 5 speed torqshift tranny on 33" tires and it came from the factory with 3.73 gears. I drove it that way for a couple years and was never happy because the tranny would shift down on every grade no matter how gradual it was. Worst part was, because it spends most of its time on dirt roads at 45-50 mph the tranny was constantly shifting in and out of overdrive. Mileage was steady at 12 mpg whether I was driving 45 mph on dirt or 75 on the highway. On the advice of a local 4x4 shop I had the gearing changed to 4.56 - and I couldn't be happier. The constant shifting problem is gone and the van is just much more responsive. Several years later and with nearly 60,000 miles on her my overall mileage - 12 mpg!
