MPG?

Most trucks are geared to be running 65-75mph in overdrive...

And around 55-65mph in direct...

If you know a thing or two about physics, you know why this is important and maybe why that "10mph rule" came about...

 

i get .1 better in utah high altitude at 75. running at 1500 rpm. then i get in cali low altitude at 55 running 1600 rpm. now i could climb a gear in cali. but that puts the rpm at 1400. engine works a little harder to maintain speed. and doesn't climb the hills as good.

granted the wind resistance is less in cali. but the rpms are higher. and 80,000 is 80,000. grabbing the next gear didn't seem to make a difference.

now you can talk about higher atmospheric pressure. more air pulling down more fuel. logically speaking. and also logically speaking. the throttle should be a little less becuase of that fact. however, climbing the hills. my turbo pressure is higher in cali then in utah. more boost in the engine equals more fuel being burned. going the same speed up the same grade of hill. my turbo will hit 30 in cali. it's lucky to hit 25 in utah.

i get .2 better with an empty trailer weighing me at 31000 vs. 80000. yes i did a 2600 mile bobtail trip to bring back a trailer the company just purchased.

there are lots of variables that come into play for fuel mileage. but since you all only went to school for economics instead of mechanics. i won't bother typing up a 100 page report.

but if you want to argue. by all means. knock yourself out.

i'm just saying what the calculator says. and the calculator does not lie.

55 vs. 75. that's 1000 miles difference over 50 hours. that's an extra trip for me per week. 2 trips if i ran strictly by the book.

i pull flat. and they only work bankers hours.

so the extra revenue gained for more loads per week far outweighs the savings in fuel you're all worried about.

but i guess miles equals money wasn't tought in school.

as far as breakdowns. nothing you can do about. going slower only delays the breakdown. it's still gonna happen.

wear and tear on the engine. much lighter loads might save on teh wear. slower speed saves on wear only if the rpms are lower. going slower but the rpms are higher is more wear. but fact is. if the engine is running, it's getting worn.

like the above post mentions. you need a full year to really break down the cost per mile. but that's kind of unrealistic. cuz your not going to have the same maintanance year over year.