Towing w/ full or empty tanks ?

[lvgator]

Should I tow my 13 ft Scamp with a full tank of water or without water?

[Francesca Knowles]

Depends...if you're towing with something really small and/or a whole lot of other payload, the hundred pounds or so might make a difference. If not- don't worry about it.

Francesca

[carlkeigley]

I usually start out with five gallons of fresh water.
We have stopped to (powder our noses) and they would be so busy
we decided to use our own powder room. Sometimes we head out
with a full tank.

[Byron Kinnaman]

Originally Posted by lvgator

Should I tow my 13 ft Scamp with a full tank of water or without water?

I find very little difference between towing when the fresh water tank is full and empty. I've gotten into the habit of leaving home with a full fresh water tank and the gray water tank empty. When I move from one place to another is there's a dump station where I'm departing from I fill the fresh water tank and empty the gray water tank.

I run the fresh water through a ceramic filter to help keep the fresh water tank clean. I sanitize the fresh water tank once a year.

We travel in the winter, gone for 3 months at a time. Shorter trips of 4 days to 2 or 3 weeks during the rest of the year.

[jerrybob]

Any extra weight can affect you gas mileage. If that's important to you.....travel as light as possible. If you're going to a campground with water.....put in 1/4 tank for toilet and fill the rest at the campsite. If you're boondocking.....might have to fill at home and carry the weight. Same goes for your holding tanks.....full tanks mean more weight. Empty your grey water at the campsite before leaving.....empty black water when near full. Good luck.

[Byron Kinnaman]

Originally Posted by jerrybob

Any extra weight can affect you gas mileage. If that's important to you.....travel as light as possible. If you're going to a campground with water.....put in 1/4 tank for toilet and fill the rest at the campsite. If you're boondocking.....might have to fill at home and carry the weight. Same goes for your holding tanks.....full tanks mean more weight. Empty your grey water at the campsite before leaving.....empty black water when near full. Good luck.

Weight has very little to do with gas mileage. It's mostly air resistance. That extra weight of water is not enough that you would ever notice it.

[Glenn Baglo]

And, 240 lbs. of beer weighs less than 240 lbs. of water.

[jerrybob]

Originally Posted by Byron Kinnaman

Weight has very little to do with gas mileage. It's mostly air resistance. That extra weight of water is not enough that you would ever notice it.

That has not been my experience. Drag is certainly a factor....but so is weight.
HowStuffWorks "How will towing affect my gas mileage?"

[jerrybob]

Originally Posted by Glenn Baglo

And, 240 lbs. of beer weighs less than 240 lbs. of water.

That is why I always empty my bladder before heading out.......

[Byron Kinnaman]

Originally Posted by jerrybob

That has not been my experience. Drag is certainly a factor....but so is weight.
HowStuffWorks "How will towing affect my gas mileage?"

I've towed my Scamp for close over 50,000 miles, with over 30,000 miles in the last 4 years. I've seen no noticeable difference between full tanks or empty tanks. If I average 60 mph or 55 mph I notice a difference. Better mileage at 55 mph.

This subject has been discussed and discussed on this forum many times with consensus that weight makes very little difference to point. A few thousand pound would probably make a difference, even very little difference between a 13' and a 16' of same manufacturer.

There appears to be a difference between flat front trailers and rounded trailers. But 300 lbs difference isn't noticeable.

[rgrugg]

Gotta agree with Byron. I always fill my fresh water tank. I'll give you an example of weight vs. air resistance. At one time we had a 30 foot Holiday Rambler travel trailer and a 22 ft Summit travel trailer. The Holiday Rambler weighed about 2000 pounds more than the Summit yet the Holiday got better mpg. Why? The Rambler had a more aerodynamic shape with rounded front corners, propane tanks enclosed inside the trailer body, and the H.R. had an enclosed underbelly. The Summit, by contrast, had the propane tanks on the tongue, was more upright in front, the front corners were sharp and not rounded, and its underbelly was not enclosed. Both trailers towed by the same truck at the same speeds under the same conditions. I suppose if all towing was uphill under stop and go conditions, then weight would probably be a factor but who ever tows like that? Additionally, having water along means we have the use of the toilet wherever we are and that has save our bacon (both of us) many times.

[Thomas G.]

Force =mass times acceleration. If you drive at a constant speed, acceleration is essentially zero, thus force due to added weight is essentially zero.

In contrast, aerodynamic force goes up with the square of the speed. The other big factors are area and drag coefficient, as seen in the first equation in the link.

Drag equation - Wikipedia, the free encyclopedia

Conclusion - drive slowly, minimize frontal area and buy a slippery designed trailer.

[floyd]

Originally Posted by jerrybob

That is why I always empty my bladder before heading out.......

For the most part...
Weight costs fuel economy through resistance to accelleration.
Drag has it's greatest impact at speed.
If you drive fast, drag will cost you at speed... and weight, not so much.
If you accellerate hard, weight will cost you more.
Both are, of course, factors.
Drag is the most important (within reasonable limits).
Water in your fresh tank will not likely cost much to carry with good driving habits.



We tow our 13D with fresh water according to anticipated need without regard to weight .
Since we have not yet "needed" gray or black water we try to keep them as empty as possible when traveling.

When we raced SCCA, we had to go to a larger TV when we switched to a closed trailer (from an open) with roughly the same car and spares.
In my experience ...Nothing tows like a Scamp

[jerrybob]

Load em up guys.......I stay with minimum weight as much as possible and drive conservatively. That includes my tow vehicle and back pack. Works for me and my mileage is better. Safe travels!

[floyd]

Originally Posted by jerrybob

Load em up guys.......I stay with minimum weight as much as possible and drive conservatively. That includes my tow vehicle and back pack. Works for me and my mileage is better. Safe travels!

Minimum has an amorphous definition.
Your TV would be lighter without fuel. Your trailer would be lighter without water. Do you carry water in your backpack?

We forgot one thing though... It is "official" administration policy that all we really need to do to save fuel is to air-up our tires.

[jerrybob]

Originally Posted by floyd

Minimum has an amorphous definition.
Your TV would be lighter without fuel. Your trailer would be lighter without water. Do you carry water in your backpack?

We forgot one thing though... It is "official" administration policy that all we really need to do to save fuel is to air-up our tires.

I also make my wife walk when we go up a hill!!

[steve dunham]

Originally Posted by floyd

Minimum has an amorphous definition.
Your TV would be lighter without fuel. Your trailer would be lighter without water. Do you carry water in your backpack?

We forgot one thing though... It is "official" administration policy that all we really need to do to save fuel is to air-up our tires.

We travel with 3 to 5 gallons of fresh water and about 1 gallon each in the grey and black water tank. We stopped at Dixon Spring SP in southern Illinois on our way home from Scamp Camp last year and there was no water available in the park so thank God for the 5 gallons we brought with us. . (Parks water system had a leak and they had lost 250,000 gallons of water in a day and a half)

Floyd : Since it is policy ,How much air should I add to my tires to get unlimited mileage?
and How come the park ranger in Dixon Springs SP had not heard of you .I was really surprised when he asked if you we're in the Illinoy legislature !

[floyd]

Originally Posted by steve dunham

We travel with 3 to 5 gallons of fresh water and about 1 gallon each in the grey and black water tank. We stopped at Dixon Spring SP in southern Illinois on our way home from Scamp Camp last year and there was no water available in the park so thank God for the 5 gallons we brought with us. . (Parks water system had a leak and they had lost 250,000 gallons of water in a day and a half)

Floyd : Since it is policy ,How much air should I add to my tires to get unlimited mileage?
and How come the park ranger in Dixon Springs SP had not heard of you .I was really surprised when he asked if you we're in the Illinoy legislature !

Infinite pressure,of course!
The park ranger doesn't get out much.
It's spelled "Illannoy" as in "sick and bothersome"!
Why don't you post on Scampers about that great looking 16SD of yours?
That stance looks really cool!

[steve dunham]

Originally Posted by floyd

Infinite pressure,of course!
The park ranger doesn't get out much.
It's spelled "Illannoy" as in "sick and bothersome"!
Why don't you post on Scampers about that great looking 16SD of yours?
That stance looks really cool!

Thanks Floyd , I completely forgot about Scamper and I will work on my spelling . You can test me next year at Scamp Camp and see how much I have improved!!

[Francesca Knowles]

Weight matters to me since so much of my 4-cyl. travel seems to be straight up a mountainside... or back down again. If I'm not worried about the clutch and/or RPMs in second gear, I'm fretting about the brakes!

Seriously, though: in my close-to-the-max setup, I fret more about the placement of the hundred pounds or so of water than I do about its presence. I like the trailer weight to be as stable as possible, and fluctuations in water level/weight in my behind-the-axle onboard tank had a negative effect on that.

That's one of the reasons I took the tank out in favor of a "gravity-feed" system: Portable 2-gallon containers that are mounted as-needed on the trailer wall, and spares distributed elswhere as the rest of the trip's load demands.

This probably wouldn't matter to most folks with bigger setups, but for my particular tug-tow combo, it does make a difference.

Francesca