Toad MPG..flat vs trailor

[CrowCross]

So, I was wondering....I was talking to a guy about towing a toad and gas milage.

He was saying flat towing gets better gas milage than a trailor because there is no tongue weight placed on the tow vehicles rear axle pushing it down...that is, if you flat tow no weight is placed on the rear axle and all of the energy is going into pulling only the toad. Sorta makes sense. What do the big brain physic guys and engineers say?

Does flat towing get better MPG than a trailer?

[EA37TS]

Too many factors involved to say for sure. Depends on:

Weight of vehicle being towed or trailered (same vehicle, different vehicles)
Aerodynamics of the trailer (open trailer or closed trailer etc...)
Weight of the trailer

Using the same vehicle (TOAD) in both scenarios would say trailering eats more fuel if for no other reason than the added weight of the trailer.

[TaftCoach]

There is still an attachment point and you are still towing something. The toad becomes a trailer in that sense. You can even put stuff in the toad and tow away. The savings comes from the lower weight.

[CrowCross]

Thanks for the reply, I was assuming they were as similiar as possible. Basically, taking a TOAD and flat towing it..then putting it on an open trailer with the same motor home pulling. Assuming the wind resistance was the same. I didn't think about weight of the trailer

I was more interested in if the tongue weight pushing down on the rear axle cut down on the MPG as opposed to simply pulling the TOAD.

[CrowCross]

Originally Posted by TaftCoach

There is still an attachment point and you are still towing something. The toad becomes a trailer in that sense. You can even put stuff in the toad and tow away. The savings comes from the lower weight.

Thanks for the reply...I'm not trying to be controversial...but when you strictly pull the guy said there is no additional axle weight which he was saying decreases the MPG...so, yes the TOAD becomes a trailer when you flat tow, but the physics are different...you have 4 wheels evenly spaced flat towing as opposed to wheels in the middle of the trailer and the tow vehicles rear wheels acting as the TOADS front wheels.

My hunch is becoming...weight is weight and it really doesn't matter.

[BeachRetreat]

Weight is weight. From a physics stand point, you'd want to put the most weight on the rolling apparatus that had the least rolling drag. Also, you want to do everything you can to reduce that drag.

Back when we were towing, we took the same trip twice, 1 year apart, within a week of each other on the calendar. Same motorhome. One towing a Honda CR-V AWD, the other pulling a GMC Yukon 4X4. Which one had the better MPG? By a significant amount it was the GMC Yukon. Why? The only thing turning was the axles, drive shaft and transfer case. With the CRV, a portion of the transmission also turned. We proved over several other trips that the Yukon was an easier pull, even though it was significantly heavier.

In the large AG tractor world, companies dedicate whole departments to this concept (called windage), because it has huge impacts to fuel efficiency and horsepower. You don't want things like gears and clutch bands turning in oil unnecessarily because it causes heat, which means its eating horsepower and your burning excess fuel.

So to your question. Take the same car from towing 4 flat that has high windage drag from the wheels and put it on a light trailer with low rolling resistance in the wheel bearings, you'd see a difference. Take a car with a true transfer case that has low resistance in the wheel bearings, axle differentials and transfer case, put it on a heavy trailer with big tires and poorly maintained axles, and the same is true in the opposite direction.

[Tockert]

I would agree that weight is weight.
More weight is going to eat up MPG!
How much though when we only get 8 - 10 on a good day?
I prefer to pay $100 per tire for our trailer than $400 per tire on the Jeep.
The Jeep tires are soft, and scrub going around corners if flat towed.
The trailer also makes it easier to backup if needed.

The difference in gas mileage when we flat towed versus on the trailer, I don't think was enough of a difference to really matter.

Todd

[SloPoke]

Originally Posted by BeachRetreat

Weight is weight. From a physics stand point, you'd want to put the most weight on the rolling apparatus that had the least rolling drag. Also, you want to do everything you can to reduce that drag.

Back when we were towing, we took the same trip twice, 1 year apart, within a week of each other on the calendar. Same motorhome. One towing a Honda CR-V AWD, the other pulling a GMC Yukon 4X4. Which one had the better MPG? By a significant amount it was the GMC Yukon. Why? The only thing turning was the axles, drive shaft and transfer case. With the CRV, a portion of the transmission also turned. We proved over several other trips that the Yukon was an easier pull, even though it was significantly heavier.

In the large AG tractor world, companies dedicate whole departments to this concept (called windage), because it has huge impacts to fuel efficiency and horsepower. You don't want things like gears and clutch bands turning in oil unnecessarily because it causes heat, which means its eating horsepower and your burning excess fuel.

So to your question. Take the same car from towing 4 flat that has high windage drag from the wheels and put it on a light trailer with low rolling resistance in the wheel bearings, you'd see a difference. Take a car with a true transfer case that has low resistance in the wheel bearings, axle differentials and transfer case, put it on a heavy trailer with big tires and poorly maintained axles, and the same is true in the opposite direction.

Great explanation! At some point the rolling resistance of the Flat-Towed vehicle's driveline (Differential, Transfer Case, Transmission-output shaft) may exceed the energy required to move the trailer. The difference is that once the trailer weight is "in motion" it does not require any more energy to keep it moving, only to overcome the rolling resistance. Compare that to the Flat-Toad where the additional rolling resistance of the driveline will continue for every mile it travels, every mile is adding to the overall wear to the driveline too.

Originally Posted by Tockert

I would agree that weight is weight.
More weight is going to eat up MPG!
How much though when we only get 8 - 10 on a good day?
I prefer to pay $100 per tire for our trailer than $400 per tire on the Jeep.
The Jeep tires are soft, and scrub going around corners if flat towed.
The trailer also makes it easier to backup if needed.

The difference in gas mileage when we flat towed versus on the trailer, I don't think was enough of a difference to really matter.

Todd

And when you consider the extra weight of the trailer - is offset by additional benefits... Todd mentions Tires being a big one along with backing up, but we can carry any of our vehicles with us as our Toad. If you happen to have more than one vehicle you might want to take with you on a trip, you can choose which one you want.

Another consideration, In the cost of a trailer - you don't need to purchase a tow Bar, Supplemental Braking System, Special Wiring Harnesses and have them installed. In our case, we don't even require an electric brake controller for our trailer.

[Dgibbster]

When it comes down to it for me it depends on how much towing you are going to do and figuring in the wear and tear also on the vehicle being towed. I prefer to service my trailer or a trailer tire over an extra vehicle repair from unused wear. Also if towing a custom vehicle an enclosed trailer is my preference but then it all depends on tow capacities and fuel costs. Now , right now, with the price of fuel, i wish i could be out off the grid somewhere leaving some more of my carbon footprint, probably the only thing i will be remembered by, towing my enclosed trailer behind my redhawk getting around 10-12 mpg.

[Grumpy]

Biggest factor with a MH is wind resistance (frontal area and speed).

When we had the 01 DESIGNER 3230 and the 08 SENECA I changed toads several times and MPG change was only a tenth or two nothing even really measurable. I tracked every gallon and mile on a spreadsheet and as I said MPG was consistent with driving at 62-65.

Went from a S-10 to a COLORADO with the DESIGNER and with the SENECA the COLORADO to a 1500 then back to a SONIC.