Free, easy way to better fuel economy

[Cubey]

There's a FREE way to get better fuel economy: Drive a max speed of 55MPH.

It seems many folks don't know the old fact that 55 MPH gives you the best fuel economy. It amazed me that a guy working for Murphy USA (Wal-Mart's brand of gas) with the tanker truck filling up the in-ground tanks for the station didn't know about the 55MPH thing.

I tried out driving a 140 mile trip (each way) at 60MPH instead of my usual 70MPH (70MPH limit) and with my 10 year old Ford E150 4.6L V8, I got better mileage without a doubt. I typically was getting about 10MPG while going 70MPH. I got at least 12-13MPG while going 60MPH. The hwy MPG on these vans when new were 12 city/17 hwy/14 combined (based on a Club Wagon). This included stops and a couple days of city driving. When I returned I had a bit over 1/4 of a tank left. Usually I end up with less than 1/4 of a tank.

So I definitely believe in the idea that going 55MPH gives you better MPG.

[Cubey]

There's a FREE way to get better fuel economy: Drive a max speed of 55MPH.

It seems many folks don't know the old fact that 55 MPH gives you the best fuel economy. It amazed me that a guy working for Murphy USA (Wal-Mart's brand of gas) with the tanker truck filling up the in-ground tanks for the station didn't know about the 55MPH thing.

I tried out driving a 140 mile trip (each way) at 60MPH instead of my usual 70MPH (70MPH limit) and with my 10 year old Ford E150 4.6L V8, I got better mileage without a doubt. I typically was getting about 10MPG while going 70MPH. I got at least 12-13MPG while going 60MPH. The hwy MPG on these vans when new were 12 city/17 hwy/14 combined (based on a Club Wagon). This included stops and a couple days of city driving. When I returned I had a bit over 1/4 of a tank left. Usually I end up with less than 1/4 of a tank.

So I definitely believe in the idea that going 55MPH gives you better MPG.

[Moder2]

Cubey, you are right on!

One of the nation's largest trucking companies for many years held their trucks back to 55 just for that reason, they finally caved to driver retention and delivery time problems, but caved in at the cost of almost $1,000,000.00 a day.

In our MH, I strictly follow the 60mph rule. I also use monitoring software (VMSpc) which gives an awesome look at what is actually going on. With my rig, pulling my F250, I am averaging over the last 7,000 miles 8.2 MPG. If I drive 65 vs. 60, I will burn almost 3 gallons an hour more, and all my temps run at least 15 degrees hotter. 3 gallons and hour is almost $9.00 an hour wasted in my eyes, for less than a 10 minute savings in time... Time might be money, but I have lots more time than money.

John

[amoose]

Sounds good .Could I see the same increase in economy if I replaced my reargear to 3:55 instead of the 4:10ratio.I'm running a 460 ford.and once while my wife was driving in the rain at night we got 11 MPG..There cuold be something to this.....

[tom wilson]

it depends on what transmission you have. if an allison you need to go fast enough to get into 6th gear. on my kountrystar i need 60 mph.

[Ray,IN]

Ever wonder about that EPA estimated highway mileage figure? It is obtained on a closed track driving a constant 48 MPH. The EPA has revised the driving course to better reflect actual mileage for owners, effective in near future. My truck gets the best mileage when towing if I drive 62 MPH.

[Vette Racer]

I question if that speed will work for all trucks as mine has to get over 61 mph to get into high gear, then the rpms are so low that it shifts down every little hill you hit which can't be good for mileage as it screams back up to speed and shifts back into 5th gear. I'd have to say it all depends on the gearing and load, not to mention power curve of the engine, as to what speed achieves the best fuel mileage.

[Two Bit]

I would agree that it depends on the engine/transmission/rear gearing. My Ford 7.3 diesel with automatic and 4.10 rear gears gets it's best highway towing mileage at 65 mph. That put the RPM's just over 2000. I use cruise control when towing. Truck never downshifts out of overdrive unless it is a big grade(then I also drop the cruise control and try to maintain 2000 rpm through the downshifts as opposed to maintaining 65 mph on steep grades).
What's the old saying...Your mileage may vary!
I get an average 12mpg towing (12,000lb tall fiver) and 17-20 empty. Even with my empty 22 foot covered livestock trailer(guessing 6000 to 7000 pounds) I get same towing mileage or maybe 1mpg better. I think it is more wind drag than weight on trailers.

[Tugboat]

I have a 2005 F150, 5.4L, 4X2 with 3.73 gears and tow a Coachman 252RKS. I have found that the best speed to tow at is set the cruse at 62MPH and I get 10.8MPG towing and 22.3MPG not towing. If I push it up to 68MPH I drop down to 8.9MPG towing and 19.6 light.

[full-timer]

I dropped from 65mph down to 55mph a couple of years ago to get better fuel economy. Each person has to experiment with their vechile to find the best range for them.

Joe

[MtManLee]

I have tried every speed from 55 to 75 with my motor home. 75 was the worst. 59-61 was the best. Difference between 55 6-6 1/2 mpg and 59-61 7-7 1/2 mpg. So I keep it at 59-61.

[offshore]

I would also look at the engine curve for output/performance, the transmission and rear axel ratio.

[Two Bit]

Now that diesel has gone to $4.00 a gallon this week, my options have dwindled down to shifting the transmission to "P" and the key to "OFF"

[Ecker]

There is no great secret here. Aerodynamic loss is a CUBIC function of speed. 2x speed = 8x HP

See chart below for an Cummins ISC diesel (one can plot for any engine)