7 Best RV Fuel Tanks For Long Distance Travel

Picture climbing a steep, isolated mountain pass with a heavy fifth-wheel in tow, only to watch the low-fuel indicator light up miles from the nearest diesel pump. For long-distance RVers and off-grid boondockers, relying solely on a stock fuel tank restricts freedom and introduces unnecessary anxiety to the open road. Upgrading to a high-capacity auxiliary or replacement fuel tank transforms road trips from stressful searches for accessible truck stops into seamless, uninterrupted adventures.

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Titan Generation V Replacement Tank: Best Overall

TITAN Fuel Tanks 7020217 XXL Replacement Diesel Fuel Tank for 2017-2024 Ford F-250 & F- 350Crew Cab, Short Bed - 55 Gallon Capacity

The Titan Generation V Replacement Tank sits at the pinnacle of fuel expansion because it replaces the restrictive factory tank underneath the vehicle, preserving precious truck bed space. Molded from military-grade cross-linked polyethylene (XLPE), this heavy-duty tank is virtually indestructible and impervious to the corrosive effects of modern diesel blends. It integrates seamlessly with the existing fuel gauge and sending unit, meaning no complicated dashboard monitors or manual transfer switches are required.

Traditional steel tanks can suffer from condensation buildup and eventual rust, which can quickly ruin a sensitive common-rail fuel injection system. Titan’s XLPE construction eliminates this risk entirely while providing a significantly baffled interior to prevent fuel sloshing during sudden stops or sharp turns. Because it mounts directly in the frame rails, the vehicle retains its original ground clearance and weight distribution, keeping the center of gravity low.

Installation is surprisingly straightforward for those comfortable with basic mechanical work, though the sheer size of the empty tank often requires a second set of hands or a transmission jack. Keep in mind that these tanks are designed specifically for diesel trucks, meaning gas-powered rig owners will need to look elsewhere. The higher upfront cost is offset by the sheer convenience of doubling the driving range without sacrificing a single square inch of cargo capacity.

This tank is the absolute best choice for full-time RVers towing heavy fifth-wheels or travel trailers with diesel tow vehicles who want maximum range without losing bed space. If the goal is a seamless, factory-like driving experience that allows driving past high-priced highway fuel stations, this is the ultimate upgrade. Do not purchase this if a budget-friendly option is the priority or if the tow vehicle runs on gasoline.

Transfer Flow 40-Gallon In-Bed: Best Premium Tank

For those who demand uncompromising engineering and intelligent fuel management, the Transfer Flow 40-Gallon In-Bed Tank represents the gold standard of premium auxiliary systems. Constructed from heavy-duty, capsule-milled aluminized steel, this tank offers superior strength and exceptional corrosion resistance. It sits flush or below most truck bed rails, allowing for easy compatibility with tonneau covers and standard fifth-wheel hitches.

The true magic of this system lies in Transfer Flow‚Äôs proprietary TRAX 4 computer-controlled operating system. Instead of relying on manual toggle switches, the TRAX 4 module automatically monitors fuel levels in both the stock and auxiliary tanks, transferring fuel on the fly via an auxiliary pump. This hands-off operation ensures the tow vehicle’s weight remains balanced and the primary tank stays consistently filled without driver intervention.

Choose this tank if hands-free convenience, automated safety features, and robust steel construction are the primary requirements. It is ideal for long-haul travelers who want a set-it-and-forget-it solution and have the budget to match. However, skip this tank if bed space is at an absolute premium or if a simple, non-electronic gravity feed system is preferred.

RDS Aluminum 72743 Auxiliary Tank: Best Slim Profile

When space in the truck bed is at a premium but extra fuel is still a necessity, the RDS Aluminum 72743 Auxiliary Tank offers an exceptionally clever compromise. Measuring just 9 inches wide at its base, this slim-profile tank hugs the front bulkhead of the truck bed, leaving ample room for generators, toolboxes, and hitch setups. Built from high-grade rust-free aluminum, it delivers a clean, classic look that resists weathering even in harsh marine or salty environments.

This tank is designed to connect directly to the vehicle’s filler neck using a simple gravity-feed installation kit, which is sold separately. A built-in float valve automatically stops the flow of fuel once the main tank is full, preventing messy overflows and fuel spills. This passive design eliminates the need for electrical wiring, reducing potential failure points to almost zero during long off-grid excursions.

This is the perfect match for the organized overlander or the RV owner who needs to pack the truck bed with gear but still wants an extra 45 gallons of diesel. Its small footprint makes it incredibly versatile across various truck bed lengths. However, if a completely automated digital monitoring system or a polymer construction is desired, look toward other options on this list.

Dee Zee Specialty Series Auxiliary Tank: Best Value

Extending the travel radius should not have to cost thousands of dollars, and the Dee Zee Specialty Series Auxiliary Tank proves that reliability can be highly affordable. Constructed from heavy-gauge Brite-Tread aluminum, this tank features internal baffles that minimize fuel movement and stabilize the vehicle’s handling. It offers a rugged, classic look with a lockable cap that provides security against fuel theft in unfamiliar overnight locations.

The simplicity of the design is its greatest strength, as it bypasses complex electronics in favor of straightforward plumbing. It is fully compatible with manual transfer pumps or gravity-feed connection kits, letting the owner decide how to integrate it into the vehicle’s fuel system. The durable welded tabs make securing the tank to the truck bed floor a quick and secure task.

While it lacks the automated digital controls of high-end systems, it performs its core duty flawlessly without requiring ongoing maintenance. The welds are clean and pressure-tested for leaks, ensuring long-term peace of mind on rough washboard roads. It is an honest, hard-working piece of equipment that gets the job done for a fraction of the cost of premium competitors.

This tank is highly recommended for budget-conscious RVers and DIY enthusiasts who want a dependable, no-frills fuel storage solution. It provides exceptional storage capacity without the premium price tag. Pass on this tank if automatic cabin-controlled fuel transfers or a hidden, under-body installation are top priorities.

Scepter 5-Gallon Military Fuel Can: Best Portable

Not every rig requires a permanent 40-gallon tank bolted into the chassis; sometimes, a highly portable, ultra-rugged backup is the smartest option. The Scepter 5-Gallon Military Fuel Can is the genuine article, built to military specifications and trusted by armed forces around the globe. Made from high-density polyethylene, this can will not rust, dent, or crush, even when subjected to extreme temperature swings or rough off-road impacts.

Unlike cheap retail gas cans that leak from cheap spouts, the Scepter features a heavy-duty, single-piece body and a secure, locking closure mechanism. This airtight seal prevents fumes from escaping, making it safe to mount on rear bumpers, roof racks, or inside van garages. Its compact footprint means several cans can be nested together, allowing for modular fuel planning based on the length of the upcoming trek.

The portable nature of these cans offers unmatched versatility, allowing fuel to be shared with a generator, a companion vehicle, or used for emergency recovery. However, pouring five gallons of fuel manually from a heavy can requires physical effort and a reliable funnel or custom spout. It is a hands-on solution that demands direct physical involvement rather than flipping a dashboard switch.

This is the go-to fuel solution for Class B camper vans, overland trailers, and small tow vehicles where space is tight and modularity is key. It offers a rugged, cost-effective safety net for off-grid travel. Skip this if towing a massive fifth-wheel where a mere five gallons of extra fuel represents less than an hour of driving time.

Moeller Marine Permanent Fuel Tank: Best Heavy-Duty

Built to survive the harsh, corrosive environment of saltwater boating, the Moeller Marine Permanent Fuel Tank brings commercial-grade durability to the RV world. This rotationally molded cross-linked polyethylene tank is completely seamless, eliminating the joint leaks common in poorly welded metal tanks. It is uniquely engineered to withstand extreme vibrations, constant sloshing, and high-impact environments without structural degradation.

Because it is designed for permanent marine installation, it features high-quality brass fittings, a mechanical direct-sight fuel gauge, and a dedicated fuel withdrawal assembly. This makes it an exceptional choice for custom RV builds, flatbed camper conversions, or heavy-duty off-grid trailers that require a dedicated fuel source for onboard diesel heaters or large generators. Its low-profile design allows it to fit under custom bench seating or within low-clearance storage bays.

This tank is the premier choice for custom van builders, flatbed camper owners, and off-grid specialists who need a dedicated, ultra-reliable secondary fuel source. It offers unrivaled durability for non-traditional mount locations. If a simple drop-in tank for a standard pickup bed is needed, a vehicle-specific auxiliary tank will be a much easier fit.

Enduraplas Fuelboss Refueling Tank: Best Poly Tank

The Enduraplas Fuelboss Refueling Tank is a self-contained, high-performance poly refueling station designed for those who need to transport and dispense fuel rapidly. Molded from an advanced, UV-stabilized polymer, this tank is engineered to handle the thermal expansion of fuel without warping or cracking. It comes equipped with a built-in 12-volt transfer pump, a high-quality hose, and an automatic dispensing nozzle, mimicking a commercial fuel pump.

This system excels in multi-use scenarios, such as toy hauler setups where toy fuel (like gasoline or diesel for UTVs, dirt bikes, and side-by-sides) is required at the campsite. The secure pump compartment keeps all electrical connections and nozzles protected from the elements and locked away from potential thieves. Its rugged, impact-resistant design stands up to heavy off-road use, making it popular among serious boondockers who set up basecamps far from civilization.

This tank is the ultimate choice for active toy-hauler owners, off-grid homesteaders, and utility-focused RVers who need to dispense fuel to multiple vehicles or equipment. It turns any truck bed into a mobile service station. Do not choose this model if the only goal is to feed the tow vehicle’s engine directly while driving down the highway.

How to Choose the Right Capacity for Your Rig

Selecting the ideal fuel capacity is a balancing act between driving range, physical space, and the vehicle’s payload capacity. Every gallon of diesel weighs approximately 7.1 pounds (gasoline weighs about 6.1 pounds), meaning a massive 60-gallon auxiliary tank adds over 420 pounds of dead weight to the truck, not including the weight of the tank itself. This weight directly reduces the available payload for the tongue weight of a trailer or the gear packed into the bed.

To find the sweet spot, calculate the tow vehicle’s average fuel economy while hauling. If a rig gets 10 miles per gallon and has a 30-gallon stock tank, the maximum theoretical range is 300 miles, with a safe highway limit of about 240 miles. Adding a 40-gallon auxiliary tank pushes that safe highway range to over 560 miles, allowing for long driving stretches between cheaper fuel stops or remote boondocking locations.

Consider the typical travel style and destination profiles before committing to a size:

• Weekend campers traveling short distances rarely need more than a 5-to-10-gallon portable backup.
• Full-time overland travelers traversing remote regions often benefit from a 30-to-40-gallon auxiliary tank.
• Heavy commercial haulers and large fifth-wheel owners may require 50-plus-gallon replacement or in-bed systems.

Remember that larger tanks require larger footprints, which can interfere with tonneau covers, fifth-wheel hitches, or storage boxes. Carefully measure the dimensions of the truck bed, paying close attention to wheel well intrusions and hitch swing clearance. It is always better to have a slightly smaller tank that leaves room for essential gear than a massive tank that forces gear to be left behind.

Safety Guidelines for Auxiliary Fuel Installation

Handling highly flammable liquids in a moving vehicle requires strict adherence to safety protocols to prevent catastrophic failures. The first rule of any auxiliary tank installation is ensuring proper venting. As temperatures change, fuel expands and contracts, creating pressure or vacuum within the tank; a high-quality rollover vent valve is essential to release pressure safely while preventing leaks in the event of an accident.

Grounding is another critical safety measure that is often overlooked by DIY installers. Static electricity can build up during the refueling process, creating a spark risk that can ignite fuel vapors. Ensuring the tank is securely grounded to the vehicle’s frame with a heavy-duty grounding strap reduces this hazard significantly. Metal-to-metal contact must be clean and free of paint or rust at the grounding point.

Legal compliance is equally vital, especially when crossing state lines. The Department of Transportation (DOT) has strict regulations regarding the transport of fuel, and auxiliary tanks must be certified for use with specific fuel types. For example, using a gravity-feed system with a gasoline engine is generally illegal and highly dangerous due to vapor pressure issues; gravity systems should only be used with diesel fuel.

Regularly inspect all mounting brackets, hoses, and clamps to ensure nothing has vibrated loose over time. Highway vibrations and rough dirt roads can rub hoses raw against sharp metal edges, leading to slow leaks or sudden failures. Protecting all fuel lines with split loom tubing and securing them away from moving suspension parts or hot exhaust pipes is a non-negotiable safety step.

Gravity Feed vs. Pump Transfer Fuel Systems

Choosing how fuel moves from the auxiliary tank to the primary tank is a fundamental decision that impacts both budget and system complexity. Gravity-feed systems rely on simple physics: fuel flows downward from the bed-mounted auxiliary tank into the lower primary tank via a specialized connection in the filler neck. This passive method is highly reliable due to its lack of electrical components, but it is strictly limited to diesel engines due to safety regulations.

Conversely, pump transfer systems utilize an electric pump to actively move fuel from the auxiliary tank to the vehicle’s primary tank at the flip of a switch or through an automated controller. This system is highly versatile, working equally well for both gasoline and diesel vehicles, and allows for precise control over when and how much fuel is moved. The downside is increased complexity, requiring electrical wiring, relays, switches, and a pump that could eventually fail.

For those seeking a budget-friendly, set-it-and-forget-it option for a diesel truck, the simplicity of a gravity-feed system is hard to beat. However, if driving a gasoline vehicle, or if absolute control over fuel distribution is desired to prevent any potential overfilling risks, investing in an active pump transfer system is the correct path. Assess personal mechanical comfort and vehicle compatibility before selecting either method.

Investing in the right RV fuel tank is ultimately about reclaiming control over the travel experience. By matching the vehicle’s payload capacity with a high-quality fuel system, the road opens up to more remote locations and fewer stressful pit stops. Choose the system that fits the tow rig’s setup, and enjoy the true freedom of the open road.