Water Weight and Miles per Gallon

[honda03842]

Roger, Hard to disagree with the physics of your statement.

[RogerDat]

Now all I need to do is a couple thousand mile camping loop to test the theory out! Last time I did that it was in the school bus camper (would have looked right at home next to your geo dome house).

That beast had 80+ gallons of water but weighed around 17,000 lbs. and got about the same gas mileage in all situations except downhill. Low enough mpg that it was ridiculous to even worry about if water made any difference.

[honda03842]

We just finished 4,000 miles. Just sitting here wishing we were back on the road.

[Victor Benz]

I agree with Norm on the fresh water issue, not much impact on gas mileage. A more important factor might be the impact on tongue weight. Most of the trailers that I've seen have the fresh water tank well forward of the axle(s), adding to the tongue weight. Reducing the weight forward of the axle by 60 or so pounds does have a measurable impact on tongue weight.

[Carol H]

Originally Posted by Victor Benz

I Most of the trailers that I've seen have the fresh water tank well forward of the axle(s), adding to the tongue weight. Reducing the weight forward of the axle by 60 or so pounds does have a measurable impact on tongue weight.

Tanks forward of the axle? Interesting. I have seen lots with the black water and hot water tanks forward but not a fresh tank. Scamp, Bigfoot and Escape's for example all have the fresh tank well behind the axle. Which trailers are fresh tanks forward of the axle? Either way it will as you say change the tongue weigh - either reduce it or increase it depending on the tanks location which may not always be a good thing especially on some of our trailers which can be fairly light on the tongue to start with....

How much lightening up the tongue weight impacts the tow depends greatly on the tow vehicle & how much weight you had on it to start with, as well as weather conditions. My previous tow vehicle was fine in pretty well most towing/weather conditions with only 10% on the tongue of the trailer. Current large tow vehicle not so good at 10% it tows better with 15%. Reasons for it are multiple - old vehicle was full time all wheel drive so a better grip to the road on the rear end than the new vehicle with 4 wheel on demand. New vehicle lighter on the back end than old - both factors allow the back end of the new vehicle to be tugged more by the trailer in side winds than the old. Distance from the rear axle to hitch of the tow vehicles is also different. Longer distance on the new vehicle than old.

[deryk]

The water tank in my Parkliner is a few feet behind the axle....but I carry 7~14 gallons extra up front in the bathroom to keep the tongue weight heavy.

[Byron Kinnaman]

I carry the full 12 gallons of water in the tank which is located 2" behind the wheel well. I've carried lots weight in stuff and little weight in stuff, more than 90lbs located both in the trailer and in the back of the truck. I could detect any differences in mpg.

[MC1]

We carry about 15 gals in our 30 gal tank which is in front of the axles. Don't notice the weight. Note we have a V6 and use a WDH.