6 Best Auxiliary Fuel Tank Kits For Extended Range Travel

There is nothing quite like the freedom of the open road, until the low-fuel light flickers on in the middle of a remote desert stretch. Extending your fuel range isn’t just about convenience; it is a critical strategy for safe, uninterrupted, and cost-effective travel in an off-grid vehicle. Choosing the right auxiliary fuel system transforms a stressful chore into a seamless aspect of your mobile lifestyle.

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

Transfer Flow TRAX 4: Best for Smart Fuel Management

The TRAX 4 system is the gold standard for those who demand precision. It functions as an automated fuel transfer controller that monitors both your main and auxiliary tanks, moving fuel as needed to keep the primary tank topped off.

This system is ideal for the technical traveler who prefers a “set it and forget it” experience. Because it uses proprietary software to calculate fuel levels based on weight and usage, it eliminates the guesswork associated with gravity-fed systems.

If you frequently navigate varied terrain or need to maintain consistent fuel weight distribution, this is the superior choice. It offers unmatched peace of mind for those who value modern, high-tech reliability over simple, mechanical solutions.

Titan XXL Replacement Tank: Best for Maximum Capacity

When interior cargo space is at a premium, sacrificing bed space for a fuel tank is simply not an option. The Titan XXL is a direct replacement for your factory fuel tank, often doubling or even tripling the OEM capacity without stealing a single inch of your living or storage area.

Designed from military-grade, cross-linked polyethylene, these tanks are built to withstand the rigors of off-road expeditions. They are lightweight, corrosion-resistant, and—most importantly—completely hidden from view.

This is the ultimate selection for van builders or truck camper owners who need to keep their footprint small and clean. It is an investment in long-term efficiency and clean aesthetics that rewards the user with thousands of miles of skip-the-pump freedom.

S&B Tanks 60-Gallon Mid-Ship Tank: Best OEM Fit

S&B Tanks have mastered the art of the perfect fit. Their 60-gallon mid-ship replacement tank is engineered to bolt directly into the factory location, utilizing existing straps and hardware for a professional-grade finish.

The beauty of the S&B system lies in its integration with the factory fuel gauge. There are no additional switches, pumps, or complicated wiring harnesses to manage, making it the most seamless upgrade on the market.

This unit is perfect for the owner who wants factory-level integration with the capacity of a long-haul rig. It is the most reliable, “plug-and-play” solution for those who want extra range without disrupting the existing architecture of their truck.

RDS Auxiliary Transfer Tank Combo: Best for Tools

For those who view their truck as a mobile workshop, the RDS combination unit is a game-changer. These tanks are specifically designed with a built-in locking toolbox, providing a secure place for gear while simultaneously feeding the main tank.

The build quality is rugged aluminum, designed to handle the vibrations and shifting loads typical of backcountry travel. The gravity-fed design is inherently simple, making it field-serviceable and easy to maintain.

If you are a working nomad who carries specialized equipment, this tank solves two problems at once. It is a robust, practical solution that maximizes utility while ensuring you never run dry in the backwoods.

Long Range America Tank: Best for Overlanders

Long Range America specializes in tanks designed for the specific demands of international and remote-area exploration. These tanks are often secondary units that complement the main tank, specifically engineered to be tucked into unused areas of the vehicle chassis.

These systems are built with heavy-gauge steel and advanced baffling, which prevents fuel slosh during extreme off-road maneuvers. They are the preferred choice for those traversing continents where fuel quality and availability are unpredictable.

If you are building a dedicated expedition vehicle intended for long-term off-grid duty, look no further. This is premium equipment for those who refuse to let fuel capacity dictate the limits of their journey.

ATTA 45 Gallon In-Bed Tank: Best Budget-Friendly Pick

The ATTA 45-gallon tank offers a straightforward, high-capacity boost to your range without the premium price tag of some complex electronic systems. It fits neatly into the bed of a pickup, leaving room for other gear while providing a significant safety net for long hauls.

While it lacks the automated features of more expensive units, its simple design is a major advantage for DIY enthusiasts. It is easy to monitor, easy to install, and consistently performs exactly as intended over the long haul.

For the cost-conscious traveler who wants to expand their range without complex modifications, this is an excellent value. It proves that you do not need to break the bank to significantly increase your time between fuel stops.

Transfer vs. Replacement Tank: Which Is Right for You?

Choosing between a transfer tank and a replacement tank comes down to your storage needs. Replacement tanks occupy the factory space, leaving your truck bed entirely open for cargo, campers, or living equipment.

Transfer tanks, by contrast, sit in the bed of your truck. This is usually the easier path for those who don’t want to drop a drive shaft or alter the factory fuel lines.

Evaluate your bed space carefully. If you are hauling a slide-in camper, a replacement tank is your only viable path. If you have an open bed, a transfer tank is often more cost-effective and easier to service.

Sizing Your Tank: How Much Extra Range Do You Need?

Calculating the right capacity requires a honest look at your vehicle’s fuel economy under load. A truck pulling a heavy trailer consumes fuel at a vastly different rate than one cruising empty on the highway.

• 100–200 extra miles: Ideal for weekend warriors and occasional road trippers.
• 300–500 extra miles: Essential for those who spend significant time in rural areas or western desert regions.
• 600+ extra miles: Necessary for specialized expedition travel and truly remote, off-grid living.

Always account for a 15% safety margin in your calculations. Relying on an auxiliary tank should be a strategic choice for efficiency, not a gamble against the empty light.

Key Safety & Legal Considerations for Extra Fuel

Extra fuel carries extra risk, particularly regarding fire safety and weight distribution. Ensure any tank you install is Department of Transportation (DOT) approved for the fuel type you are carrying.

Improperly vented tanks can create vacuum issues or pressure build-ups that damage your fuel system. Always use the manufacturer-recommended installation kit, which typically includes high-quality hoses, check valves, and rollover protection.

Finally, be mindful of your vehicle’s Gross Vehicle Weight Rating (GVWR). A full 60-gallon tank of diesel weighs roughly 420 pounds; this load must be factored into your total cargo capacity to avoid suspension failure or dangerous handling characteristics.

Installation: Is This a DIY Job or One for a Pro?

Gravity-fed auxiliary tanks are well within the capability of an experienced DIYer with basic mechanical knowledge. The process usually involves mounting the tank, running fuel lines to the fill neck, and installing a rollover valve.

Replacement tanks are a significantly larger project. They require removing the original tank, which often means supporting the chassis or removing the truck bed, and handling volatile fuel lines.

If you are not comfortable working with fuel systems or lack the necessary lifting equipment, consult a professional. A professional installation provides the peace of mind that comes with a pressure-tested, leak-free system that will reliably serve you for years to come.

Investing in an auxiliary fuel system is one of the most practical upgrades for anyone committed to a mobile lifestyle. By carefully selecting a tank that fits your specific mechanical and space requirements, you effectively remove one of the greatest constraints of nomadic travel. Prioritize safety, respect your vehicle’s weight limits, and enjoy the confidence that comes with knowing you have the fuel to go further than the rest.