Aux Fuel Tank is 2005 Ram 3500 Dually

I put a used reefer tank that I had here in my pkup. 50 gal. NICE to have the added range. Buy cheaper fuel. Gravity feed to filler tube. Reefer tanks have a gauge on the end, so I have rough idea how full it is.

AngryBert-63 wrote:
Of course weight makes a difference.

The EPA says that for every 100 pounds taken out of a vehicle, the fuel economy is increased by 1-2 percent.

We're 'stop and smell the roses' travelers. I like to stretch my legs every few hours anyway - no need to add unnecessary weight.

I like to stretch my legs also but not at a fuel stop. I can pick my fuel stops and not have to worry about what the fuel gauge is reading or time my stops. I can stop when I want, where I want and it don't have to be a fuel station. I can always get fuel when I'm not hooked to the camper instead of trying to fine a station big enough for my rig. A lot of places I camp are 40 miles or more out in the boonies and away from big lots. Ever try to get an 80' rig into a country store diesel pump that's usually to the side up next to the building? That's why I have one.

Of course weight makes a difference.

The EPA says that for every 100 pounds taken out of a vehicle, the fuel economy is increased by 1-2 percent.

We're 'stop and smell the roses' travelers. I like to stretch my legs every few hours anyway - no need to add unnecessary weight.

I added a 60 gallon RDS aux tank almost as soon as I got the truck. I honestly have no idea how it changed the performance or the MPG of the truck.

Really don't know if it saves me any money in fueling either. Probably does at times, but that is not why I bought it.

The reason it works great for me is that I NEVER have to worry about where I am going to fill up when I am towing my 5er and boat tandem. I can stop to take a break when I want to, not when I need to. No worries about pulling into a busy, loud, dirty truck stop. I can stop at rest stops, and take as much time as I need.

I love my aux tank. Don't really know or care if it saves me cash.

A lot of RV haulers have them. The effect on mpg is minimal, 3/4 ton pickup trucks are built to haul. Wind resistance is the mpg enemy, not weight.

Adding 900 lbs. to your truck is going to lower the amount you can carry though. I went with a 40 gallon auxiliary tank because I didn't want to lose several hundred pounds of hitch weight capacity.

Of course just because you have it doesn't mean you have to fill it to capacity every time.

I have a 63 gal aux tank on my Ram and have not seen any change in fuel mpg. There are times that I save as much as 50 cents per gal. I can travel over 1000 miles before I need fuel.

freddmc wrote:
Some people say the added weight of the fuel negates any savings gained from buying fuel cheaper. Any thoughts.

It depends.

If you tow in the mountains a lot weight makes a BIG difference. Any driver with a TV down on HP can tell you that. Normal towing on relatively flat roads? No, it makes no difference once you get the weight up to speed. It's almost all aerodynamics then.

I would put it in. That way you have a choice on filling it up or keeping it empty.

Choices are good. :)

#2 diesel weighs 7.2#/gallon (US).............115 gallons/828#

I have a 35 gallon OEM tank.....I run out of 'drive time' before I do fuel :B

A 'free' tank I might consider installing.
But wouldn't purchase as I couldn't justify.

I have a 110 gal diesel tank in the back of by truck. I keep it mostly full all winter for the weight. I don't keep track of my mileage, and technically it has to effect my fuel usage, but I can't say I notice any difference, so it has to be small.

Bill