Im with you i dont know why but i average 5.3 to5.6 no matter what speed or weight in flats or mountains.

So, what does? Are you want to say, that going 75mph into 30mph cross wind, you'll get the same mileage, as going 60mph in the same wind, with the same load? Why don't you try to compare apples to apples?
And about "550hp+ fuel guzzlers"...It's not what you got, it's how you use it.

same m.p.g. at any speed, terrain, & weight? this is a first I have heard of such results. I have definitely never experience this myself.

:lol2::lol2::lol2:

Think whatever you want to ding dong. I've been driving 57 for over 3 years and I have at least 4 other friends who have been doing it for 2 or more years. At least 1,000,000mi of personal experience and not one of us have had an accident.

If your truck gets horrible (and anything under 6.5 mpg I consider horrible) fuel mileage no matter what speed you drive, there is something mechanically wrong with it and you should get it fixed.

Laugh and shake your head all you want. I used to have a "cool" truck that averaged 5.17 mpg for the entire year. I've made $10,000 more in 10 months of this year then I did the whole last year with my "cool" truck driving 70. I've done that in 106,000 miles, home every weekend and occasionally during the week. :clap:

I don't know. I think there's too many variables to say that one single, definite thing has the 'most' effect. But if one says that speed accounts for 5% of the pie, and other variables each count for 4.9% and less, then it would be the 'most'. I just don't think it is. I think it changes constantly.

When I encounter 30mph sustained crosswinds (which usually come with higher gusts) while I'm empty, I will drop my speed considerably and I still get 4.5mpg, just the same as if I drove 75. I know that because I'll do 75 in a big crosswind when I'm loaded and guess what: I get 4.5

The only way that I could say that speed would play such a significant role in your fuel mileage, would be if you were a dedicated run kind of guy. Because things change so much over the course of the day, it would be hard to say that it plays such a high percentage of your fuel consumption. To each his own though.

I was speaking of driver behaviour. Out of "sweet spot", accelerating from a stop, idling etc... the speed he chooses to drive at has the largest effect.

When you have a stiff side wind, the speed chosen to cruise at becomes even more important.

I never said 5.56mpg was good, and I have been seeking ways to increase it. But shake your head all you want the results I am getting is what I AM GETTING. But I refuse tyo be an ROAD HAZARD by going slower than the flow of traffic. That is Dangerous and one reason I got my own Truck so I would not be a danger on the Highway. Going Slower is not safer, but causes a DANGER.

I go 60 mph all the time, how is that a danger?

i've been thinking about this thread alot the past few days.

maybe my theory about how you take off and where you shift is motor.


as i said before my s60 gets great milage short shifting..

while my truck was down i had a columbia with a acert c15.. 5.86 mpg... ran 70 @1500 rpm i short shifted it and babied the hell out of it.. oh and it was a 410 hp motor.