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Truck Bed Fuel Tanks: Easily Expand Poor Towing Range and Save Money

A truck bed fuel tank is an excellent investment for many RVers and those driving long distances in a truck. They’re great for extending the time between stops at the fuel pump and minimizing fill-ups in states or regions with expensive fuel prices. In fact, we were able to pay for the entire fuel tank in fuel savings over a few years of traveling in an RV! Read on to learn more.

What Is a Truck Bed Fuel Tank? 

A truck bed fuel tank sits in the bed of a truck and stores fuel. The tank typically serves as an auxiliary tank for a truck’s fuel supply. Some tanks will automatically feed into the truck’s fuel tank.

Truck bed fuel tank
This pickup bed has an auxiliary fuel tank that feeds directly into the truck’s fuel tank.

We could get over 1500 miles range with our 75-gallon additional fuel tank when not towing! Even when towing, you can easily extend your range by several hundred miles before stopping to refuel.

How Do Truck Bed Fuel Tanks Work? 

There are typically two ways a truck bed fuel tank works. An inline gravity feed or small pump will replace the fuel in your fuel tank as the engine burns it. This will continually fill your tank until your auxiliary tank is empty. When direct tank filling is used, it’s usually called a transfer tank because the fuel is only used for transferring to the vehicle and extending range.

tapping into fuel lines on tank for bed fuel tank
To use a transfer pump or gravity fill you will need to tap into the fuel lines on the tank under the bed of your truck.

The second way is by using a 12-volt electric pump to temporarily connect the tanks. You can flip a switch to activate the pump. Then, the pump will push the fuel from the truck bed fuel tank into the truck’s factory-installed fuel tank. To avoid any issues, you should watch your fuel tank gauge and turn off the pump before you reach full to avoid over-filling your tank. 

The last way tanks can be used is by adding a fuel fill handle similar to what you see at a fuel station. The pump can be activated then you can fill the tank just like you were filling at a fueling station to empty the truck bed tank.

This type of electric pump can also fill other vehicles or machines that need refueling. These are commonly used for those running ATV’s and dirt bikes.

Fill-Rite FR1210HA 12V 15 GPM Fuel Transfer Pump...
  • Durable cast iron pump housing built to withstand the wear and...
  • Removable junction box allows for easier installation
  • Thermal overload protection prevents motor from overheating

Did you know? You can add a truck bed fuel tank to just about any pickup truck – a Ram, Ford, Chevy, or even a Toyota Tacoma.

Holding Capacity of a Truck Bed Fuel Tank

There are several different models and types of these auxiliary fuel tanks. Some include a toolbox or are made from different materials, but all serve the same general purpose.

You can find tanks ranging from 40 to 85 gallons or more. The size of the auxiliary fuel tank will largely depend on the amount of available space in your truck bed. However, adding an extra 40 gallons to your truck can often double your fuel capacity, which is never a bad thing.

How Much Do They Cost? 

A truck bed fuel tank can cost anywhere from $800 to $1,200 or more for the most expensive units. The cost of your fuel tank will depend on how the manufacturer made it and the size.

AM-TANK 58 Gallon Capacity Portable Durable…
  • Gas Caddy Durability: Durable 58-gallon tank offers a lightweight…
  • Fuel Caddy Built: Made from roto-molded polyethylene with…
  • Transfer Tank Efficiency: Has forklift pockets, handles for easy…

Increasing your fuel tank also means increasing the cost each time you refuel. When you double or triple your fuel capacity, you’re also doubling or tripling the cost of filling up.

Factors to Consider Before Adding a Truck Bed Fuel Tank

There’s a handful of things you should consider before adding a truck bed fuel tank to your vehicle. Let’s take a look!


These fuel tanks aren’t cheap. They’re built to last and often come with a premium price tag as a result. Alternatively, because they last so long, you can sometimes find a good deal on a used one.

We our first-bed fuel tank we got used for only a few hundred dollars.

Also, you’ll pay more overall each time you stop to fill up your tanks. Instead of buying 25-35 gallons of fuel, you could be purchasing 100 gallons or more!

Additional Weight 

Not only will the fuel tank itself add weight, but the fuel will as well. This can easily add hundreds of pounds to the weight on your truck’s axles and frame. If you’re up against the payload capacity on your truck, you may need to shop for a smaller truck bed fuel tank.


When considering which size to get for your fuel tank, keep in mind that a large tank in the bed of your truck will take up precious storage space. If you’re not traveling long distances, you’ll likely need to make a list of pros and cons for putting a fuel tank in your bed.

If you’re only taking a handful of extended trips, it’s likely not going to be worth your time or the precious storage space. However, if you’re regularly traveling or want to avoid filling up when fuel is more expensive, get the largest possible fuel tank for your truck.

Installing a Titan Sidekick Fuel Tank on Ford Ranger

How Often You’ll Use It

You may not realize it, but fuel eventually goes bad. So if you install a fuel tank and aren’t traveling, the fuel could expire. If you’re using your tank for gas, make sure you can use the fuel within three to six months.

Diesel, however, has a longer shelf life at around 2 years when properly stored. Using old fuel in your truck or other machinery can cause your engine and fuel system damage. 

Benefits of a Truck Bed Fuel Tank for RV Life

There are several benefits to installing a fuel tank in the bed of your pickup. Let’s look at a few.

Save Money By Going Farther Without Filling Up

By increasing your fuel tank capacity, you’re able to go much farther without stopping to fill up. This can allow you to not only save time but money as well.

Truck towing a Winnebago Micro Minnie on the freeway
Auxillary fuel tanks allow you to drive farther without stopping for fuel.

You may find that you’re traveling through a state or area of the country that has notoriously high fuel prices. You’ll love being able to pass on through these areas without having to stop to fuel up. We have an article about saving money on fuel that works best if you have a long-range.

If you’re hoping to make a cross-country trip while RVing, a truck bed fuel tank can be extremely convenient. You could potentially go an entire day without filling up. 

Lessen the Need to Take Your RV Through a Gas Station

Many RVers who use a diesel truck can utilize the trucker fuel lanes found at truck stops. These typically provide a tremendous amount of room for maneuvering and are extremely convenient. However, not everyone RVing drives a diesel truck.

Very few gas stations have conveniently located gas pumps for those towing an RV with a gas vehicle. Standard fuel pump lanes can be tight, and even an experienced RVer may get a bit nervous navigating. Some gas stations may also not have enough vertical clearance to fit an RV under the awning covering the gas pumps.

Even with a truck bed fuel tank, you’ll eventually have to stop at a gas station. Make sure you know your RV’s height before you pull in: What Is Your RV Height, and Why Do You Need to Know It?

Truck with travel trailer filling up at gas station
Gas stations can be tricky to navigate with an RV. Having a truck bed fuel tank means you’ll visit them less often. When you do have to stop to refuel, consider signing up for a diesel discount program like TSD Open Roads.

By installing an auxiliary fuel tank, you eliminate the need to take your RV through a gas station every few hours. Depending on the size of your tanks, you’re likely going to have enough fuel to get you through a whole day of towing.

Being able to say goodbye to stressing out over tight gas station lanes is a tremendous benefit for many RVers.

Alternative Options To In Bed Fuel Tanks

Carrying portable fuel cans is the least expensive option that can still increase your range. While they cannot carry near as much fuel it’s not a bad idea to at least have one can in the bed of the truck as a safety in case you ever find yourself near-empty far from a fuel station.

Pro Tip: You can get battery-powered electric pumps to help transfer fuel from portable tanks cleanly and easily.

Deway Automatic Fuel Transfer Pump with Auto-Stop,…
  • SIPHON ANYTHING IN SECONDS | Easy, Multipurpose Electric Transfer…
  • WIDE PUMP COMPATIBILITY | Hose is Made of Highly Durable…
  • SIMPLE ON/OFF OPERATION | Just Screw the Siphon Directly Onto The…

Another great option is to add an under-bed high-capacity tank. These are custom-designed tanks that replace your factory tank for your particular truck. The most popular manufacturer of these tanks is Titan Fuel Tanks.

installing an underbed high capacity fuel tank
Installing a high-capacity underbed tank might be more work than someone wants to take on; in-bed tanks are much easier.

Is a Truck Bed Fuel Tank Right for You? 

Whether a truck bed fuel tank suits you or not depends on your travel style. If your preferred camping style often results in staying in campgrounds or relatively close locations, you likely won’t benefit much from adding additional fuel capacity.

However, if you’re traveling full-time or using a large amount of fuel, it can be an incredible upgrade.

Would you benefit from adding a truck bed fuel tank to your RV setup? Or do you already have one? Let us know in the comments.

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About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

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Charles Land

Saturday 10th of February 2024

We've had a 55 gallon bed tank and agree with your points - greater cruising range, avoid exhorbitant prices and fill up at lower priced (and hard to maneuver) convenience stores when not towing. I would caution readers with gasoline powered trucks that many of the bed tanks on the market are diesel only. There are extra requirements for a bed tank to store gasoline safely.

Mark Seibel

Sunday 24th of July 2022

Tom; Last I knew Pilot / Flying J no longer gives the discount with open roads.

Michael H Rechtien

Thursday 6th of January 2022

Is it legal to have a truck bed tank for gasoline. I was told it isn't

Charles Land

Saturday 10th of February 2024

@Michael H Rechtien, Most bed tanks are diesel only. There a few that are rated for gasoline.

Mortons on the Move

Tuesday 8th of March 2022

Yes they are legal if they conform to DOT requirements.

John Lockhart

Sunday 24th of October 2021

When I had a short bed 2500 to tow a fifth wheel, the 26 gallon tank was definitely a limiting factor. I installed an approximately 35 gal. tank from Northern Equipment. Being a diesel truck, it could be set up as gravity feed, directly into the fuel filler tube. A shutoff valve on the tank could be used if I wasn't traveling. This extended capacity was a game changer.

Now I have a 1500 Silverado Duramax 3.0 that I use to tow a small 22' trailer. Even at 12 mpg towing, fueling isn't an issue since I can take my little truck into the truck lanes!