Tow Speed

[Tezha]

Is there a speed that gives the best MPG or does it depend on the TV.

[Donna D.]

It depends on the tug. Each vehicle will have a "sweet spot" based on the trailer being tugged and route of travel. My F-150 gets the best mileage while towing at about 58-59 mph on the flats. Drops like a rock the faster I drive and more mountains I need to climb. I'd rather go slower and leave some $$ in my pocket. YMMV

[Raya]

I think a lot of it has to do with wind resistance, but that said, as Donna mentioned, there are many variables with tow vehicle, engine, camper, etc. There's really no way to put a general number on it, except to say that (due to the wind resistance factor), a slower highway speed probably always better on fuel, as long as it is appropriate for the road and for the rpms of your vehicle (no lugging!).

Raya

[Chester Taje]

Ease off on the gas pedal and keep tires inflated to proper air pressure. I have driven or towed my units at just under 60mph.

[floyd]

When towing with my Escape 4CYL,about 58MPH does the trick, slower gives little gain, faster gets costly quickly, on my Ranger 4.0 that spot is about 64MPH.
Gearing and Engine type are important, as are wind resistance and grade, fuel quality, vehicle maintenance, tire size and pressure, and overall weight.
Rapid ACCELERATION is the most expensive automotive thing you can buy, and it costs by the pound.

The opposite of a tow vehicle....
My 95 Mustang produced it's best highway mileage at 80MPH...
Lots of HP and low end torque + great aerodynamics + 2:73 gear with 275/45 R17 tires and overdrive = 2000RPM @ 80MPH just barely touching the bottom of it's efficiency. OF course with no trailer! [lol]

[Byron Kinnaman]

As has been said many things effect best mpg and tow speed. However there's another or two to consideration when towing. ST tires are generally rated for 65 mph max. Also many states have a maximum towing speed of 55 mph. In our case here in Oregon it's not well published, but is in the laws. California posts maximum towing speed. To avoid speeding tickets check the state laws you'll be towing in or do as I do always tow between 55 mph and 60 mph. I like to stay closer to 55.

Byron

[Roger C H]

Air resistance factor goes up as the SQUARE of the speed.

40 mph = 1600

for a 125% increase in speed you pay a with a 156% increase in drag

50 mph = 2500

for a 120% increase in speed, you pay with a 144% increase in drag.

60 mph = 3600

and compared to 40 mph for a 150% increase in speed you get a 225% increase in drag.

Which is why auto mfgrs try to keep their air resistance figures low.

[CD Smith]

I have said it before and it is worth repeating.

Towing or not, my Escalade gets its best MPG at 30 MPH with cruise control engaged. Engine speed is just above idle.

Anything speed above that and it gets worse and worse.

There's an old myth, repeated again and again by over the road truck drivers, "My truck is geared to get the best MPG at 70 MPH".

It is also a myth that your "MPG sweet spot' is any MPH above zero.

This is not 'rocket science' its 'physics'. Every revolution of your engine takes a specific amount of fuel. If you think your 'sweet spot' is 80 MPH a 2,000 RPM, you woulfd be amazed what it would be if you just lower your RPM by 1500.

IMHO

[RSchleder]

I generally run about 60mph when towing my 13' Scamp. I guess I'm concerned about those 13" tires spinning too fast at speeds much higher.

[GeorgeR]

Originally Posted by CD Smith

I have said it before and it is worth repeating.

Towing or not, my Escalade gets its best MPG at 30 MPH with cruise control engaged. Engine speed is just above idle.

Anything speed above that and it gets worse and worse.

There's an old myth, repeated again and again by over the road truck drivers, "My truck is geared to get the best MPG at 70 MPH".

It is also a myth that your "MPG sweet spot' is any MPH above zero.

This is not 'rocket science' its 'physics'. Every revolution of your engine takes a specific amount of fuel. If you think your 'sweet spot' is 80 MPH a 2,000 RPM, you woulfd be amazed what it would be if you just lower your RPM by 1500.

IMHO

I agree that speed has a lot to do with towing fuel efficiency but that relationship is not completely linear. Towing at maximum torque (my 7.3l diesel Ford maximum torque is at 1600 RPM) will likely be most efficient. Towing at RPMs below and above the power band (between peaks of maximum torque and power) will not be efficient especially above power peak.
George.

[Frederick L. Simson]

Originally Posted by Tezha

Is there a speed that gives the best MPG or does it depend on the TV.

I have found that my Tachometer is the 1st gauge to follow for maximizing mpg, and my Speedometer is a modifier for road conditions. I try to keep it at 1500 rpm's or lower, and really get amazing fuel economy at 1000 rpm's. However, I have found that since I strengthened the frame on my Fiber Stream which raised it by 2", most freeway speeds happen closer to 2000 rpm's. Any speed above 2500 rpm's really sucks the gas.

As a Californian, I set my cruise control to 55 mph when towing, stay in the right lane, and allow everybody else to pass.
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[floyd]

Originally Posted by Roger C H

Air resistance factor goes up as the SQUARE of the speed.

40 mph = 1600

for a 125% increase in speed you pay a with a 156% increase in drag

50 mph = 2500

for a 120% increase in speed, you pay with a 144% increase in drag.

60 mph = 3600

and compared to 40 mph for a 150% increase in speed you get a 225% increase in drag.

Which is why auto mfgrs try to keep their air resistance figures low.

You make a legitimate point here, this is one of the reasons that a Scamp tows so much easier than most other trailers.

[floyd]

Originally Posted by CD Smith

I have said it before and it is worth repeating.

Towing or not, my Escalade gets its best MPG at 30 MPH with cruise control engaged. Engine speed is just above idle.

Anything speed above that and it gets worse and worse.

There's an old myth, repeated again and again by over the road truck drivers, "My truck is geared to get the best MPG at 70 MPH".

It is also a myth that your "MPG sweet spot' is any MPH above zero.

This is not 'rocket science' its 'physics'. Every revolution of your engine takes a specific amount of fuel. If you think your 'sweet spot' is 80 MPH a 2,000 RPM, you woulfd be amazed what it would be if you just lower your RPM by 1500.

IMHO

While one could easily take issue with most of the misapprehensions in your post, the most vulnerable is the first sentence, next would be that
"IMHO" thing.<_<

[floyd]

Many TVs are designed to run the air conditioner in several settings, including those which involve "defrost". The air conditioner can adversely affect fuel econmomy, to varying degrees, If you don't need it on don't run it.

Preemptively....<_<
Yes, I have heard the data on rolled down windows and air conditioning.

Frederick;
Another guage which used to be common and installed for watching fuel consumption is the Vacuum guage.
The thing worked pretty well, but it was distracting, tedious and annoying when used properly.{lol}

[HikeSticks]

Originally Posted by Tezha

Is there a speed that gives the best MPG or does it depend on the TV.

I wondered the same thing. To find out, I bought a Scanguage II. (No association; about $150.). It connects to your OBD2 port under the dash on all cars 1995 and newer (just a straight plug in). It shows four data items at a time, which can be changed, including current MPG and average MPG. You can switch between reading for the trip, tank, today and yesterday.
Basically, the slower you go, the better the MPG. I have a manual transmission and I wondered if it's better to downshift and when; downshifting burns more gas.
When on the interstate, I try to stay around 55 if I'm not holding up traffic. If I'm planning a long trip, I use a spreadsheet I made to determine what my costs will be a various average speeds to help me decide if the extra time it will take me is worth the savings.
Good luck!
Barrie

[Carol H]

My Subaru tells me what my gas milage is currently and on average for a trip, how far to the go to next gas up etc. Its intreasting to watch it change. There is no saying what the sweet point is - all depends on where you are driving. :-) On an average trip on the coast I average on a trip about 23 MPG.

The worse gas milage I have ever seen the car dash display was towing on a hill in the Cascades with a serious head wind - was only doing about 40 and the gas milage read 7 mpg! Thankfully things did not stay that way for long.

[Raya]

Originally Posted by Frederick L. Simson

I have found that my Tachometer is the 1st gauge to follow for maximizing mpg, and my Speedometer is a modifier for road conditions. I try to keep it at 1500 rpm's or lower, and really get amazing fuel economy at 1000 rpm's.

1000 rpm seems really low to me, but then I suppose each vehicle is different. Below about 2000, my car would be seriously lugging with a load. That is, I could certainly still drive, but it would be hard on the engine. I try to keep my rpm up over 2000, especially if I'm "asking" anything of the engine.

I guess it's something to check for your own vehicle.

Raya

PS: "Remember when" moment: Remember when gas mileage first became a big deal, and they sold cars (manual transmission) with an "upshift" light for best gas mileage? Only they had you shifting at such low rpm that you got great mileage but it was terribly hard on your engine (poor "enginage")

[mcbrew]

I have an instant MPG and tank MPG display on my dash. I have noticed that under a good load (towing up a hill, for instance), that I sometimes get better fuel economy by downshifting to 4th gear. The RPMs are a bit higher, but I guess it puts the engine into a more efficient part of the torque band.

[Bryan L.]

At 70mph with a AWD Town and Country minivan, I get 11.5 mpg. 70 is definitely not the sweet spot!

[mcbrew]

To add to my previous post: I got about 23-24 MPG towing our 13' Scamp up to Gettysburg last weekend. This was our first trip with it, so I don't have that much experience. There are nothing but hills between here and Gettysburg. These aren't mountains (okay, they were a few million years ago), but a few hundred feet up and down, over and over has an impact on fuel economy.

In just under two weeks, we'll be taking a trip to Maryland's eastern shore for a weekend of camping. This is a much flatter drive. I hope to get 1 or 2 MPG better on this trip. I'm not all that disappointed with 24 MPG, but I wouldn't mind better fuel economy!