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?
