I've been a TC guy(still have) and I just bought a 19'Toyhauler. The reason was the tank capacity as I boon dock all the time and usually at least a week or two. Showers will be nice after riding off road. My question is it has 100 gal. fresh tank and that's appx. 1200lbs. I drive a Duramax, How much do you think the difference in milage is with full water as apposed running empty? I ask cause a lot of times I can see finding a place to get water could be a real PIA. Also I'll have a empty truck to use.

Unless you are going up and down a LOT of hills or mountains, or doing a ton of starts and stops, then the weight of the water will not make any difference in your fuel mileage. It is the frontal area of the rig that makes the difference and the speed at which you tow it - not the weight. Once that weight gets rolling it takes very little HP to keep it going.Barney

BarneyS wrote:Unless you are going up and down a LOT of hills or mountains, or doing a ton of starts and stops, then the weight of the water will not make any difference in your fuel mileage. It is the frontal area of the rig that makes the difference and the speed at which you tow it - not the weight. Once that weight gets rolling it takes very little HP to keep it going.Barney I tow it about 60-65 when possible. I know what your saying so what would you estimate the difference if driving mountains? I live in the desert but I go to the mountains, everything is up from here...

You wont be able to figure a difference with 1200# added weight.

No noticeable difference. Wind resistance is by far the most significant factor in gas mileage for speeds over 30 mph.

I have 10 years of data when towing my old trailer with my 06 DuraMax. 12 MPG over the years average. Bought a new trailer that is taller and 4K heaver. In a 1,100 mile trip with quite a few mountains I got 1.3 MPG less. 10.7 MPG. Speed was around 65 or so.Barney and the rest are telling you the truth.

MPG difference? | Good Sam Community

20 Replies

bikendan
Explorer
Oct 07, 2017
atreis wrote:
No noticeable difference. Wind resistance is by far the most significant factor in gas mileage for speeds over 30 mph.

THIS^^^^^^^
rhagfo
Explorer III
Oct 07, 2017
Wild Card wrote:
You wont be able to figure a difference with 1200# added weight.

X2
That said use the 150 gal of water to balance the toys in the garage.
ScottG
Nomad
Oct 07, 2017
I just went to a new TT that's almost a foot taller and a ton heavier.
So far it looks like I lost 1 mpg (at the most) but I need to do further testing.
moresmoke
Explorer
Oct 07, 2017
I have a 6800 lb high profile TT and a triaxle gooseneck flat bed that is usually loaded to 19000 with a couple tractors. Similar towing routes, I get 1 mpg less with the TT.
1320Fastback
Explorer
Oct 07, 2017
I say less than .5mpg difference. Wind resistance is a bigger factor than a little bit more weight.
Turtle_n_Peeps
Explorer
Oct 07, 2017
I have 10 years of data when towing my old trailer with my 06 DuraMax. 12 MPG over the years average.

Bought a new trailer that is taller and 4K heaver. In a 1,100 mile trip with quite a few mountains I got 1.3 MPG less. 10.7 MPG. Speed was around 65 or so.

Barney and the rest are telling you the truth.
atreis
Explorer
Oct 07, 2017
No noticeable difference. Wind resistance is by far the most significant factor in gas mileage for speeds over 30 mph.
Wild_Card
Explorer
Oct 07, 2017
You wont be able to figure a difference with 1200# added weight.
tuna_fisher
Explorer
Oct 06, 2017
BarneyS wrote:
Unless you are going up and down a LOT of hills or mountains, or doing a ton of starts and stops, then the weight of the water will not make any difference in your fuel mileage. It is the frontal area of the rig that makes the difference and the speed at which you tow it - not the weight. Once that weight gets rolling it takes very little HP to keep it going.
Barney
I tow it about 60-65 when possible. I know what your saying so what would you estimate the difference if driving mountains? I live in the desert but I go to the mountains, everything is up from here...
BarneyS
Nomad
Oct 06, 2017
Unless you are going up and down a LOT of hills or mountains, or doing a ton of starts and stops, then the weight of the water will not make any difference in your fuel mileage. It is the frontal area of the rig that makes the difference and the speed at which you tow it - not the weight. Once that weight gets rolling it takes very little HP to keep it going.
Barney

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MPG difference?

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