On flat ground and cruising as low as you can go and maintain speed without mashing the pedal, It's hard to explain but you have the jist of it.
410 with no overdrive will get good mileage at 55 and thats close to 2500. 3.55 gears don't seem to get as good at the same rpm but you are running a little faster increasing the amount of horsepower to maintain it. This has been my experiance.

This is the princaplle that big trucks use for the very best mileage.
#1 low profile tires, there is less rolling resistance the shorter the side wall is.
#2 tall rear end gears and no overdrive, it is a proven fact that overdrive gears use more horsepower and create more heat, heat is is energy and any and all heat takes horsepower to make includeing the brakes.
#3 aero dynamics

This depends on the usuall loads that a company huals, a heavy haul co has to have lower rear gears to get the load started , so they are more efficient with more gears and overdrive and sometimes even double over.

 

I cant give an exact number yet, but i know its in the 18-20 mpg range.

 

I drive like a grandpa when im buyin my own fuel lol .. 50 mph average and i get about 17-20

 

I guess we have you to thank for all the restrictions on young drivers.

My all time best single fillup was 24.9MPG averaging 65-70. This was likely with a slight tailwind however. Exact same route on the way back returned 19.5 MPG a couple hours later, so the average for that day was ~22.5MPG. All I remember is the truck was running smooth and quiet with cruise control on most of the time and hardly ever dropping out of overdrive even on steeper hills. EGTs never got above 650 if I remember right.

I averaged several trips back in the summer of 08 and all of them averaged out to 19-20 MPG.
All of that was running empty or very close to empty. Usually I am towing however.

Towing the 20' flatbed trailer at those same speeds usually returns 15 MPG on average, but if I can control myself, 16 or 17 does happen sometimes. If I'm in a hurry and don't care, 13 MPG is possible. Recent trip in a rainstorm averaged about 13MPG between 80-85 MPH.

That day an SUV still nearly blew my doors off when it passed me. Down the line, I saw it upside down in the ditch with EMS already on scene. Guess traction control isn't all it's cracked up to be when running LP tires that are best used on sterilized counter top.

Fuel prices are going up again, so I guess I should temper my right foot for this summer.

 

i usually keep the cruise set at 50........

 

David many many things that were done in the name of fun when I was a kid will land you in jail now. I truly feel sorry for the younger generation. The thing that strikes me as wrong the generation that passes all the laws are from the time when it was called fun. I think all the kids that got picked on or never learned to stand up for themselves try to change the world in the name of safety. But I also know quite a few that were wild when they were younger that don't want their kids to ever experiance that.

 

Safety at the expense of freedom. Strange how we still repeat that mistake, isn't it?

We do need law and order, but personally, I think we have a little too much of the former and not enough payoff in the latter.

 

Common sense is what we need, not more laws that attempt to instill common sense.

Back in our day, distractions while driving were limited to 8 track tapes and maybe a CB radio.

Now we have cell phones, TEXT MESSAGING, and mobile internet on top of DVD players, GPS and 50 other devices.

Last Thursday, two rearend accidents within a mile of each other while I was on my way home from work.
First thing I told my son when I got home, I sure hope you watch your rear view mirrors when you stop to turn left while riding your motorcycle.
Either of those accidents would have been serious for a biker.

One of them happened in the other lane right in front of me, she drove right into the car stopped to turn left.
Tell me she was paying attention to driving the car.

 

tell me about it, i watched this purty little blonde chic in a focus just talkin away on her phone go right through a red light and peg a toyota..... its like, wow how clueless are most people today. Im in the younger generation, and apparently im one of the few that got handed a little common sense... personally i blame it on growing up on a ranch 100 miles from "civilization"

 

I think I've answered a cell phone call while driving maybe 2 or 3 times in my whole life. Every time I wasn't really comfortable with it. Now I keep it off or at least have the ringer off. Leave a message and I'll get back to you at the next stop. Most of the time its a wrong number anyway and I don't need to get billed for that.

Driving with a hand held phone is illegal in my province now. Hands free is allowed only for fully licensed drivers (no learner or novice licensed people). I think CB radios are still allowed. Thinking I might get one eventually just to have an extra ear to the ground on the longer trips. I also have a camera mount on my dash.....

 

21.4 is my best so far.

 

My previous 86' reg cab, 4x4,4sp, averaged 22mpg empty, 18 loaded. My dads 87' reg cab, 4x4, ZF5 averages 24 empty. This was back in the 55 mph days, usually running 62-63 because you could get away with it generally. Dad said he lost a bit of mileage the last couple years and was getting 22-23. Looked a his tires and he had gone to a taller tire from the originals so no lost mileage.

My cummins gets 15.7 empty. Speed limit on open freeway is 75, drops to 65 in heavy traffic areas and sometimes 55. To get real good mileage out of the cummins I'd need 3:08 gears and dbl overdrive. Probably get into the 25 mpg range then. Can't get good fuel mileage running against the governor all the time.

We have enough laws on the books. Far to many in fact. Many of the current laws are duplicates, just worded differently. Then they make new laws when enforcement of the laws already on the books would suffice.

You can't legislate common sense or intelligence but it seems that is the intent. Less law and more accountability would be a great start.

 

its illegal to talk on the phone and drive here.im waiting for it to be illegal to talk or listen to the radio.
i tend to bend the rules being every window in my truck is tinted including the windshield....so what they cant see dont hurt right?lol!!!!!!!some folks can multi-task and drive for example" hey star can you reach the beer in the back seat?i just spilled mine." just kidding!!!!!!!! i do not condone drinkin and driving i seen to many friends spill their beer......i mean get in trouble for it

 

8000lb truck, 2400 rpm's, 65mph = 14.5 mpg nock the r's down to around 1900 and mph around 50-55 = 16mpg

add 14-15 thousand pounds behind it and I lose about 3 mpg.

Warmups kill it and fluctuating the throttle. I usually use cruise control.