For vehicle owners who require extended range, operate equipment in remote locations, or simply want to minimize fuel stops, an auxiliary fuel tank can be an invaluable addition. In our evaluation, we researched and compared a wide array of auxiliary fuel tanks, scrutinizing manufacturer specifications, published industry standards, and aggregating extensive owner feedback.
Our goal is to provide an evidence-based buying guide, highlighting the strengths and limitations of each product to help you make an informed decision based on your specific needs, whether for a truck, RV, or industrial application. We focus on critical factors like capacity, material durability, installation complexity, and safety features to present a clear picture of what each tank offers.
| Photo | Product | Score | Buy |
|---|---|---|---|
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Transfer Flow 080011559 Auxiliary Fuel Tank System Best Overall Integrated System Integrated computer-controlled fuel transfer |
9.0 | 🛒 Check Price |
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TITAN Fuel Tanks 50 Gallon Auxiliary Fuel Tank Runner-Up for Large Capacity Cross-linked polyethylene construction, 50-gallon capacity |
8.6 | 🛒 Check Price |
 |
RDS 72545 Auxiliary Fuel Tank Best Aluminum Transfer Tank Diamond plate aluminum, 45-gallon capacity |
8.3 | 🛒 Check Price |
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Weather Guard 35 Gallon Auxiliary Fuel Tank Premium Build Quality Heavy-gauge aluminum, 35-gallon capacity |
7.9 | 🛒 Check Price |
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Dee Zee DZ91752 Auxiliary Fuel Tank Practical & Reliable Choice Non-vented aluminum, 50-gallon capacity |
7.6 | 🛒 Check Price |
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GPI 100 Gallon Fuel Transfer Tank High Capacity Workhorse Heavy-duty steel, 100-gallon capacity |
7.3 | 🛒 Check Price |
 |
Scepter Duramax 14.5 Gallon Fuel Caddy Portable & Convenient Polyethylene, 14.5-gallon portable fuel caddy |
7.0 | 🛒 Check Price |
1. Transfer Flow 080011559 Auxiliary Fuel Tank System: Best Overall Integrated System
Based on owner feedback and the spec sheets, a notable limitation of the Transfer Flow system is its installation complexity. While the integrated design offers superior convenience and safety once operational, the initial setup often requires professional installation due to the sophisticated wiring and plumbing involved with its automatic transfer system. This can add to the overall time and effort before the tank is fully functional.
Those seeking a simple, manual transfer tank for occasional use, or who prefer a lower initial investment, may find this system to be more than they need. Its advanced features and integrated design are best suited for users who prioritize a fully automated, long-term solution for extended range without manual intervention.
- Constructed from 12-gauge aluminized steel for robustness
- Utilizes a patented fuel transfer control technology
- Available in multiple capacities to suit various truck models
Pros: Seamless, automatic fuel transfer operation; High-quality, corrosion-resistant construction; Designed for specific vehicle integration and compliance
Cons: Requires professional installation for optimal performance; Higher initial investment compared to basic transfer tanks
2. TITAN Fuel Tanks 50 Gallon Auxiliary Fuel Tank: Runner-Up for Large Capacity
In our evaluation, the TITAN Fuel Tanks 50 Gallon Auxiliary Fuel Tank, while highly durable, does present a characteristic of polymer tanks: susceptibility to expansion and contraction with significant temperature fluctuations. While this is generally managed by the design, it can sometimes lead to minor variations in perceived fuel levels or fitting tightness if not properly accounted for during installation and usage. Owner feedback indicates this is typically a minor concern but worth noting.
This tank is not ideal for those who frequently operate in extreme, rapidly changing temperature environments where metal tanks might offer more stable physical properties. Furthermore, users who prefer a completely rigid, unyielding structure might find the slight flexibility of a polymer tank less appealing, even though it contributes to its impact resistance.
- Made from military-grade, rust-proof polymer material
- Designed to fit securely in most truck beds
- Includes a sending unit and wiring harness for easy gauge integration
Pros: Exceptional resistance to corrosion and dents; Lighter weight than comparable metal tanks; Comes with components for monitoring fuel levels
Cons: Polymer material may expand/contract more with temperature changes; Requires careful securing to prevent movement in the truck bed
3. RDS 72545 Auxiliary Fuel Tank: Best Aluminum Transfer Tank
Based on owner feedback and the spec sheets, a common point of consideration for the RDS 72545 Auxiliary Fuel Tank is that essential installation hardware, such as mounting kits and transfer pump, are typically sold separately. While this offers flexibility for users to choose their preferred components, it means the total setup requires additional purchases beyond the tank itself. This might not be immediately obvious for first-time buyers.
This tank might not be the best choice for individuals looking for an all-inclusive, ready-to-install package right out of the box. Users who prefer a complete system with all necessary accessories included, or those on a very strict budget who want to avoid piecemeal purchases, should consider other options that bundle more components.
- Constructed from heavy-duty 3/16 inch aluminum for durability
- Features a lockable cap for security and anti-siphon protection
- Designed with internal baffles to reduce fuel sloshing
Pros: Robust aluminum construction resists corrosion; Internal baffles enhance driving stability; Commonly compatible with various transfer pumps
Cons: Installation hardware typically sold separately; Aluminum can be susceptible to dents from heavy impacts
4. Weather Guard 35 Gallon Auxiliary Fuel Tank: Premium Build Quality
In our evaluation, while the Weather Guard 35 Gallon Auxiliary Fuel Tank boasts impressive durability, its heavier construction due to the robust aluminum can be a drawback for some users. This increased weight, while contributing to its strength, means it will add more static load to the vehicle, potentially impacting payload capacity or fuel efficiency slightly compared to lighter polymer alternatives. Owner feedback indicates this is a minor trade-off for its build quality.
Individuals who are strictly mindful of vehicle weight limits, or those seeking the lightest possible auxiliary fuel solution for recreational use, might find this tank to be overkill. It is primarily designed for demanding, professional applications where longevity and resistance to abuse are paramount, and where a few extra pounds are less critical than overall ruggedness.
- Built with durable 0.125 inch thick aluminum material
- Features a reinforced design for demanding use
- Integrated baffles minimize sloshing and maintain stability
Pros: Exceptional durability and resistance to wear; Secure lid design helps prevent fuel theft and spills; Optimized for professional and heavy-duty applications
Cons: Heavier than some alternative tanks of similar capacity; Requires separate purchase of a fuel transfer pump
5. Dee Zee DZ91752 Auxiliary Fuel Tank: Practical & Reliable Choice
Based on owner feedback and the spec sheets, a key limitation of the Dee Zee DZ91752 Auxiliary Fuel Tank is its non-vented design, which necessitates careful attention during fuel transfer. Without an integrated vent, users must ensure proper venting mechanisms are in place externally or during the transfer process to prevent vacuum lock or over-pressurization, which can hinder efficient and safe fuel flow. This adds a step to the operation that some other tanks handle automatically.
This tank is less suitable for users who prefer a completely hands-off, automatically vented system or those new to auxiliary fuel tanks who might overlook the importance of manual venting during operation. Individuals seeking maximum convenience and simplicity in their fuel transfer process might find this design less user-friendly compared to tanks with integrated venting solutions.
- Constructed from heavy-gauge aluminum material
- Designed for use with gravity feed or pump transfer systems
- Features a black powder-coat finish for corrosion resistance
Pros: Good balance of capacity and footprint; Durable powder-coat finish adds protection; Relatively straightforward installation for experienced DIYers
Cons: Non-vented design requires careful monitoring during transfer; Some owners report the fuel gauge can be inconsistent
6. GPI 100 Gallon Fuel Transfer Tank: High Capacity Workhorse
In our evaluation, a significant drawback of the GPI 100 Gallon Fuel Transfer Tank is its substantial weight, even when empty, due to its heavy-duty steel construction and massive capacity. This weight, combined with 100 gallons of fuel, places considerable demands on a vehicle’s payload capacity, suspension, and overall handling. Users must carefully verify their vehicle’s gross vehicle weight rating (GVWR) and axle ratings to ensure safe operation. Owner feedback consistently highlights the need for a robust truck to carry this tank.
This tank is not recommended for light-duty trucks, half-ton pickups, or users who frequently need to maximize their vehicle’s remaining payload for other gear. It is best suited for heavy-duty trucks, flatbeds, or dedicated service vehicles where payload capacity is less of a concern and the need for a very large volume of fuel outweighs the weight penalty.
- Constructed from 12-gauge steel for rugged applications
- Designed for use with fuel transfer pumps, sold separately
- Large capacity ideal for commercial or agricultural needs
Pros: Massive fuel capacity for extended operations; Robust steel construction can withstand harsh environments; Wide compatibility with various heavy-duty transfer pumps
Cons: Very heavy, significantly impacts vehicle payload; Steel construction is susceptible to rust if paint is compromised
7. Scepter Duramax 14.5 Gallon Fuel Caddy: Portable & Convenient
Based on owner feedback and the spec sheets, a primary limitation of the Scepter Duramax 14.5 Gallon Fuel Caddy, when considered as an “auxiliary fuel tank” in the broader sense, is its relatively small capacity and manual transfer method. While excellent for portability and smaller equipment, 14.5 gallons provides only a modest extension of range for most full-size vehicles, and the hand pump can be slow and physically demanding for transferring larger volumes. Its safety score is slightly lower due to the manual handling aspect which introduces more potential for spills if not careful.
This caddy is not suitable for users seeking a permanent, high-capacity, or automatic auxiliary fuel solution for their primary vehicle. It is best skipped by those who need significant range extension or demand rapid, effortless fuel transfer. Its ideal application is for refueling ATVs, lawn equipment, generators, or as an emergency reserve, rather than a primary vehicle auxiliary tank.
- High-density polyethylene construction resists corrosion
- Equipped with pneumatic tires for easy portability
- Features a patented flow control valve and fuel gauge
Pros: Extremely portable for various applications; Integrated pump and hose for immediate use; Corrosion-proof and lightweight material
Cons: Smaller capacity limits its use as a primary auxiliary tank; Manual pump operation can be slower than electric pumps
Frequently Asked Questions
What is the primary purpose of an auxiliary fuel tank?
The primary purpose of an auxiliary fuel tank, also known as a transfer tank, is to extend a vehicle’s driving range, transport fuel for equipment, or provide a backup fuel supply. We researched how these tanks allow users to carry additional fuel safely and efficiently, reducing the need for frequent stops and ensuring fuel availability in remote areas or for long hauls.
Are auxiliary fuel tanks legal in all states?
Based on our research, the legality of auxiliary fuel tanks can vary by state and local regulations, particularly concerning capacity, mounting, and fuel type. Most states permit their use for personal or commercial purposes, but it is crucial to verify specific regulations in your area and any states you plan to travel through. We compared published guidelines and found that proper installation and compliance with DOT regulations are key.
What materials are commonly used for auxiliary fuel tanks?
In our evaluation of manufacturer specifications, auxiliary fuel tanks are commonly constructed from aluminum, steel, or high-density polyethylene (HDPE). Aluminum tanks are popular for their corrosion resistance and lighter weight. Steel tanks offer superior durability and impact resistance, often chosen for heavy-duty applications. Polyethylene tanks are lighter, rust-proof, and often more resistant to dents.
How is fuel transferred from an auxiliary tank to the main tank?
Fuel transfer methods vary based on the tank design. We compared systems that include gravity feed, electric fuel pumps, or manual hand pumps. Gravity feed systems rely on elevation difference, while electric pumps offer faster and more convenient transfer, often with automatic shut-off features. Manual hand pumps are common for smaller, portable caddies, requiring more effort but offering simplicity.
What safety considerations are important for auxiliary fuel tanks?
Safety is paramount for auxiliary fuel tanks. Based on industry standards and owner feedback, critical considerations include proper venting to prevent pressure buildup, secure mounting to prevent movement or spills, and ensuring the tank material is compatible with the fuel type. We also emphasize using appropriate transfer pumps and hoses, and always adhering to manufacturer installation guidelines to prevent leaks and fire hazards.
Our Verdict
After extensive research and comparison, the Transfer Flow 080011559 Auxiliary Fuel Tank System stands out as our top pick for its sophisticated, integrated design and automatic fuel transfer capabilities, offering unparalleled convenience and safety for serious users. The TITAN Fuel Tanks 50 Gallon Auxiliary Fuel Tank earns our runner-up position, providing an excellent balance of large capacity, robust polymer construction, and resistance to corrosion, making it a reliable choice for extended range.
