I have an 08 F350 short wheel base, with 6.4 Powerstroke and I want to add more fuel capacity so I can pick when I want to fuel up, rather than worry about if I am in range of a fuel station.

I have decided that I am going to get a 50 to 60 gallon transfer/aux toolbox in bed tank that I can re-use from truck to truck.

There are many options that effect the cost and weight of the tank. Are internal baffles a must have option? It seems to me that there is a variance of weight in the tanks of nearly 100 lbs, the lighter tanks are more expensive, but have no baffles in them. Is adding 400+ lbs of fuel and 100+ lbs of tank to an F350 even that big of a deal anyway?

My fifth wheel adds about 3000lbs to the bed, and I have Firestone ride rite bags installed. Thanks for any advice.

 

I plan on doing mine as soon as I can get my wife off the $800 for the tank/tool box...

 

I bought a 91 gallon tank that fit my 1987 F250 from either Harbor Freight or Northern tool. From what I hear if you have a tank over 100 or 110 gallons you have to get all kinds of labels saying what your carrying.

 

Internal baffles are not important IF (and only if) you only operate with the tank either full or empty.

The weight itself won't be an issue with a properly mounted tank at the front of the bed of an F350 -- the problem comes when the fuel sloshes from side to side during a turn, especially an S-curve or similar maneuver.

When the tank is either full or empty, there is no problem with the weight shifting, but if you go into a turn with half a tank of fuel, the weight will shift to the outside -- the quicker the turn, the faster the weight shift and the more drastic the effects.

The absolute worst case would be a half-tank, and you suddenly need to swerve around the non-driving-fool who just pulled out in front of you or who just had something drop off his vehicle.

The weight is well above the truck center of gravity, so having it shift suddenly can make maneuvers very interesting.

 

He is dead correct. VERY INTERESTING.

Diesel fuel has a weight of 6.951 pounds/gallon on the low end. You are talking at least 347.55 pounds (50 gal tank) transferring to the outer radius of the turn all at the same time. That, multiplied by the distance above CoG, along with tongue weight of the trailer makes one hell of a mass shift. The less the mass shifts, the less effect there is on control. Having the weight that far above the Center of Gravity (CoG) can actually cause the truck to roll over in emergency situations.

This all depends on tire inflation, other weights and their placement, suspension components and their condition and a myriad other factors. Best and safest is to have baffles in the tank to prevent slosh.

 

I'm looking at one of these:

The lid conceals the filler cap and and adds an extra bit of security at $4 a gallon.

(and it has baffles)

 

That looks like a good tank, RPM.

BTW, I designed a tank for my dad. It was 77.5gal, the width and depth of the bed and had 5 baffles (1 side to side, 4 front to back). He reports no issues with slosh weight from it.
I had to design it to fit under a side load ATV rack / bed cap he had designed. He needed access to the tank with 2 ATVs on the bed and the cap closed. Made an interesting design challenge.

 

I like that design better than the 2 piece "Lego" setup I see with most tanks and toolboxes. Not only does it advertise you have fuel to steal, it makes it easier to get to.

The only drawback to the combo design is a smaller toolbox.