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An auxiliary petrol tank is the difference between stopping for fuel every couple of hours and powering through a full day of work or travel. Whether you are towing a fifth wheel across the plains, running a generator during a storm, or building a dedicated track car, adding an extra fuel tank means you choose when and where you refuel — not the other way around. The catch? Finding one that bolts on without headaches, holds fuel safely, and matches your actual vehicle or equipment.
I’m Min — the founder and writer behind Gadgets Feed. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
From a 45-gallon bed tank that a single person installs in under two hours to a 1.3-gallon auxiliary that extends a dirt bike’s range, here is a comprehensive look at the best auxiliary petrol tank options available right now.
Our Picks at a Glance
How To Choose The Best Auxiliary Petrol Tank
An auxiliary petrol tank is not a one-size-fits-all purchase. The right pick depends on your mounting location, fuel type, and desired extra range. Knowing these three factors prevents buying a tank that doesn’t fit or fails on first use.
Capacity and Physical Size
Capacity is the headline number, but the tank’s physical dimensions are just as important. A 45-gallon rectangular tank takes up a substantial footprint in a truck bed, while a slim 1.6-gallon cylinder can fit behind a seat or under a hood. Measure your available space before you shop — and remember that a full tank of fuel adds significant weight right where you mount it.
Material and Build Quality
Aluminum is the dominant material for most auxiliary tanks because it resists rust and stays relatively lightweight. Steel tanks are heavier and can rust over time, but they are often less expensive and very durable when properly coated. The quality of the welded seams, the thickness of the metal, and the included hardware all determine whether the tank will hold up to vibration, weather, and years of use.
Included Components and Sender Accuracy
Many tanks come with a fuel level sender, cap, and mounting brackets. A sender that fails within weeks (a common frustration with budget-priced cells) turns a good tank into a guessing game. Check whether the sender matches your gauge’s ohm range — 0–90 ohms and 3–90 ohms are both common standards but they are not interchangeable. Also look for features like anti-slosh foam inside the tank, which stabilizes fuel delivery during cornering or off-camber driving.
Quick Comparison
| Model | Best For | Capacity | Material | Fuel Type | Amazon |
|---|---|---|---|---|---|
| RDS 45 Gal Rectangular★ Best Overall | Truck Towing | 45 gallons | Aluminum | Gasoline | Amazon |
| Acerbis 1.3 Gal Front TankDirt Bike Range | Motorcycle Range | 1.3 gallons | Plastic/Painted | Gasoline | Amazon |
| JSD 1.63 Gal AluminumCompact Cylinder | Small Engines | 1.62 gallons | Aluminum | Gasoline | Amazon |
| 20 Gal Fuel Cell Parts-Diyer | Generator Backup | 20 gallons | Aluminum | Gasoline | Amazon |
| GSTP 15 Gal Fuel Cell | Street & Track | 15 gallons | Aluminum | Gasoline | Amazon |
| EVIL ENERGY 12 Gal Fuel Cell | Budget Builds | 12 gallons | Aluminum alloy | Gasoline | Amazon |
| GSTP 17 Gal Fuel Cell | Compact Fit | 17 gallons | Aluminum alloy | Gasoline | Amazon |
| SUPERFASTRACING 19 Gal Top Feed | Off-Road Durability | 19 gallons | Aluminum | Gasoline | Amazon |
| Edicapo 20 Gal Fuel Cell | Complete Kit | 20 gallons | Aluminum | Gasoline | Amazon |
| Better Built 36 Gal Steel Tank | Diesel Work Trucks | 36 gallons | Alloy Steel | Diesel | Amazon |
| RDS 63 Gal Wedge Tank | Max Range Towing | 63 gallons | Aluminum | Diesel | Amazon |
In‑Depth Reviews
1. RDS MFG INC 71083 Rectangular Auxiliary/Transfer Fuel Tank – 45 Gallon Capacity
Our pick — over 4.5★ from 90+ verified ratings; the strongest balance of quality and price.
The 45-gallon tank that fits a short-bed Ram and takes one person under two hours to install.
This is the no-compromise option for long-distance towers who hate frequent fuel stops. The RDS tank is made from fully welded aluminum, which means it will never rust out no matter how many winters you drive through. It holds 45 gallons of gasoline (diesel users, take note — this unit is designed for gasoline), and owners consistently report that the quality of the welding and the billet fuel cap feels premium. The install on a 2016 Ram 2500 short bed took roughly two hours, with the hardest part being cutting the metal fill tube on the truck.
The tank sits slightly above the bed rails, but owners still see over it easily and note that it leaves the bed usable for a toolbox or fifth-wheel hitch. The recurring caution is packaging — multiple units arrived with bent mounting brackets because of minimal shipping protection, though the tank itself was undamaged. The consensus is that this is a well-built, straightforward way to add serious range, with owners saving money by bypassing high-priced fuel stations on long hauls.
Rugged rectangular transfer
- 45-gallon capacity in a manageable rectangular package that fits many full-size short beds.
- Quality of the aluminum build and the billet fuel cap get consistent praise across nearly two dozen reviews.
- Owners routinely complete the install in under two hours with basic tools.
Heavy steel build
- Shipping protection is minimal — a few buyers received theirs with bent mounting brackets they had to hammer straight.
- No installation instructions are included; phone support is available but having a veteran mechanic buddy helps.
Best for farm use: you need maximum gasoline capacity in a truck bed and are comfortable with a little DIY on the fill neck and brackets.
Skip for tight spaces: you want a diesel-specific tank or expect pristine packaging with full instructions.
2. Acerbis Front Auxiliary Fuel Tank (1.3 Gallon) (White)
A 1.3-gallon add-on that turns a two-stroke into a backcountry explorer.
This is the smallest tank on the list and the only one designed specifically for motorcycles. The Acerbis front auxiliary tank mounts to the handlebar area of most dirt bikes and trials bikes, adding 1.3 gallons of fuel without requiring a massive frame modification. Owners of Sherco trials bikes and various dual-sports praise it as a straightforward way to push past the range anxiety that comes with small stock tanks. The universal fit claim holds up, though some owners needed to cut the included sleeves down and swap bolts for the correct sizes.
This tank transforms the ride experience by eliminating range anxiety. One owner fitting it to an older Sherco called it a quick fix for a leaking original tank, using the fuel tubing through the old cap. Another summed it up neatly: “adds range for longer rides without worrying about running out of fuel.” It is lightweight, painted white to resist heat, and requires no complex plumbing — a simple, effective solution for trail riders who want to stay out longer.
Compact white tank: If you ride off-road and have ever pushed a bike back to the truck, this upgrade prevents that. It bolts on, holds enough for a serious day ride, and does not weigh the front end down.
Best for dirt bikes: you own a dirt bike, trials bike, or dual-sport and want an extra hour or two of ride time without a larger main tank.
Skip for long trips: you need a universal fuel cell for a car, truck, or stationary generator — this is strictly a motorcycle add-on.
3. JSD 1.63 Gallon 6″ x 15″ Auxiliary Aluminum Fuel Tank Cell Gas Tank Center Fill 1/4″ NPT Outlet
A spun aluminum tank so compact it fits a barstool racer or a vintage Wisconsin engine.
Where most auxiliary tanks demand a dedicated corner of a truck bed, this JSD cylinder slips into tight spaces where nothing else fits. At 1.62 gallons and measuring 6 inches in diameter by 15 inches long, it is built for applications like small engines, custom go-karts, barstool racers, and stationary generators. The spun aluminum construction is a classic hot-rod aesthetic, but owners warn that the finish is rough — a functional, brushed look rather than polished chrome. One owner paired it with a 1955 Wisconsin 10 HP engine and reported that 3/4 gallon gives roughly 1 hour of runtime.
The quality of the welding and three-year warranty offer genuine value., with one owner noting that his local welder would charge around to build the same thing. The two included powder-coated steel brackets make mounting straightforward, but note that the fuel cap does not vent, which caused a vacuum lock for one owner until they swapped in a John Deere cap (AM3892T). Also plan on cleaning out any metal shavings left from manufacturing before you connect it to your fuel system.
Aluminum 1.63 gallon: For anyone building a custom small engine project or needing a compact fuel cell for a generator, this is the affordable, readily available solution that works — just budget a few minutes for cleanup and a vented cap upgrade.
Best for compact fit: you have a tight mounting space and need a durable aluminum tank with a three-year warranty.
Skip for high capacity: you require a polished finish or a ready-to-run setup with a vented cap — you will need to buy one separately.
4. 20 Gallon Fuel Cell Aluminum Fuel Tank 80L Fuel Gas Tank | Universal Racing Street Drift Strip with Level Sensor, Silver
A 20-gallon fuel cell that turned a Florida hurricane prep into a single-refuel operation.
This Parts-Diyer 20-gallon cell measures 19.75 inches long by 24 inches wide by 10 inches tall, a footprint that fits many truck beds, race car trunks, and generator pads alike. The standout story from the reviews is an owner who plumbed this tank in series with a 32-gallon tank for a combined ~60 total gallons, feeding a generator that burns about 1 gallon per hour. During Florida hurricanes, that setup drastically reduced refill runs — a real-world example of what this tank can do beyond its intended street/race application. The tank includes anti-slosh foam, a 0–90 ohm fuel level sender, and dual -10 outlets with dual -10 vent outlets.
The recurring frustration is the fuel sending unit. Multiple buyers report that the included sender failed quickly, making the gauge useless. One reviewer went through two senders before giving up. The tank itself is praised as good quality for the price and easy to install, but the sender is a known weak point. If you are using this for generator duty, you may not need the sender anyway. For track or street use, budget for a replacement sender from a known brand.
Large 20 gallon
- Versatile size that works equally well in a race car, truck, or generator setup.
- Anti-slosh foam and dual 10AN outlet/vent ports provide serious plumbing flexibility.
- Buyers found it easy to mount, connect fuel lines, and fill — even on 50-year-old generators.
Bare aluminum shell
- The included fuel level sender is unreliable — multiple owners mention failure shortly after install.
- If you are building a stationary setup, you will likely need to remove the anti-slosh foam and adjust the float arm.
Best for bulk fuel: you need a large, affordable fuel cell for a generator or a race car build and plan to replace the sender with a known brand.
Skip sender included: you want a plug-and-play setup with a reliable fuel gauge straight from the start.
5. Universal 15 Gallon 60L Fuel Cell Tank with Cap and Level Sender Polished Aluminum Black
A polished 15-gallon fuel cell that blends hot-rod style with proven everyday function.
This GSTP cell is the mid-capacity choice that slots between compact track cells and massive bed tanks. The 15-gallon capacity fits hot rods, street racing builds, trucks, and SUVs equally well. The polished aluminum exterior looks the part in an exposed trunk or bed mount, and the black cover provides a clean two-tone appearance. Owners consistently describe it as good value — “the quality is amazing for the price” is a typical reaction — and the installation is simple enough for a first-time fuel cell user. Dual 10AN outlets and dual 10AN vent outlets give you flexibility for return-style fuel systems.
The anti-slosh foam inside helps maintain consistent fuel delivery during aggressive cornering. Where this tank draws mixed feedback is build quality — some owners find it well made, while others call it cheaply constructed for the price tier. The functionality gets positive marks across the board, with owners reporting no leaks, easy hose connections, and accurate level readings after dialing in the sender. For the money, it is a reliable starting point that looks the part and delivers on the basics.
Universal 15 gallon: A capable mid-range fuel cell that gives you 15 gallons of capacity, a polished finish, and the basic fittings you need — just inspect the foam and sender closely before final install, as quality can vary from unit to unit.
Best for budget builds: you want a sharp-looking polished aluminum cell for a street car or custom build at a price that leaves room for better plumbing.
Skip for sender ready: you need a heavy-duty tank for off-road abuse or require precise build consistency without any quality variance.
6. EVIL ENERGY 12 Gallon Fuel Cell Gas Tank Aluminum with Level Sender Street Drift Silver
A 12-gallon budget cell that delivers strong value — as long as you accept the risk of weld leaks.
The EVIL ENERGY fuel cell is the most popular choice by sheer volume on this list, and the reason is simple: it works for a wide range of builds at a very accessible price. Measuring 19.9 inches by 18 inches by 9.05 inches, it fits in trunks, truck beds, and even some unusual spots like a 99 Honda Civic converted to AWD. The tank is made from 1060-H24 aluminum alloy with a plastic cover, and it includes a built-in 3–90 ohm level sensor plus internal anti-slosh foam. Owners praise the quality of the aluminum and the overall value for money, with the built-in sensor working well with aftermarket gauges when the sender matches correctly.
The honest trade-off is durability. The most-discussed negative by far is leakage, with nearly 15 owners reporting weld cracks near the ports or other areas after limited use. The installation itself draws mixed feedback — while many find it easy, others point out that the tank ships without fittings, so you need to buy those separately (an additional – if you want the version with fittings included). Check the foam regularly for deterioration, as the manual advises, and pressure-test the welds before you mount it permanently.
EVIL ENERGY 12 gallon
- Compact 12-gallon size with a built-in 3–90 ohm level sensor that works with many aftermarket gauges.
- Owners consistently praise the build quality of the aluminum itself and the overall value for the money.
Sender not included
- Leakage around weld joints is the most common complaint, with multiple reports of cracks developing near the ports.
- Fittings are not included, so budget extra time and money for AN fittings unless you buy the pre-packaged version.
Best for street use: you are on a budget, have a multi-fuel project (gasoline or methanol), and are comfortable inspecting and potentially sealing welds.
Skip for off-road: you want a guaranteed leak-free setup from the start or prefer a tank that includes all fittings in the price.
7. 17 Gallon Fuel Cell with Cap Level Sender Street Drift Aluminum Silver
A 17-gallon shallow cell that fits under tonneau covers and low-clearance builds.
This GSTP fuel cell measures 29.5 inches long by 17 inches wide by only 7 inches tall, making it one of the shallowest options in the mid-capacity range. That low profile is a lifesaver if you are mounting under a tonneau cover, inside a utility body compartment, or anywhere vertical space is tight. It comes with a 12-foot CPE fuel line kit and a 0–90 ohm level sender, plus 8AN inlet and outlet fittings. Owners praise the solid construction and secure welds. One owner who installed it in a rock-crawling rig reported it held up great after four years under the Arizona sun, with no cracks or paint failure.
The honest downsides are usable capacity and lack of baffling. One owner who measured carefully found that the label says 15 gallons but actual usable capacity is closer to 12.26 gallons, plus an unfiltered supply tube leaves about 1.5 gallons unusable. There are no internal baffles, so in a vehicle that sees hard cornering, fuel slosh can be an issue. The tank does include a roll-over vent, which is a nice safety touch. Overall, it is a solid, straightforward fuel cell that works best in applications where a low height is the priority and the full labeled capacity is not a hard requirement.
17 gallon drift style: The short take: If you need a wide, flat fuel cell that slides into a low space, this is your pick.
Best for drift cars: vertical clearance is your biggest constraint and you need a low-profile 17-gallon (labeled) cell with a roll-over vent.
Skip for daily driver: you cannot afford to lose 4–5 gallons of usable capacity or need internal baffles for high-performance cornering.
8. 19 Gallon Aluminum Top Feed Fuel Cell Gas Tank+Cap+Level Sender 72L Black
A 19-gallon top-feed cell that survived four years of rock-crawling abuse without a single crack.
The SUPERFASTRACING 19-gallon fuel cell is the pick for serious off-roaders who need a tank that can take impacts and keep working. It measures 29.5 inches long by 12 inches wide by 12 inches tall, a clean rectangular footprint with a top-feed design and a 1.75-inch filler neck. The defining owner story is a rock crawler who installed this cell about four years ago: it has held up great under Arizona sun, the paint has not cracked despite constant bouncing over rocks, and there are no leaks. This kind of long-term abuse is the ultimate test for any fuel cell, and this one passed.
The persistent issue is the fuel transfer system. Multiple customers note that the fuel pick-up tube was defective from the factory, causing the pump to lose prime after about 20 seconds of running. The sending unit is also a common failure point — one owner went through two that failed, noting that the company refunded the cost of a replacement but the hassle was real. The tank quality itself gets strong marks, and the black painted finish holds up well, but this is a situation where you may need to modify or replace the pick-up tube and sender to get a reliable setup.
19 gallon top feed
- Four years of hard rock-crawling with zero cracks or paint failure — a real-world durability test passed.
- Generous 19-gallon capacity in a manageable 12-inch-wide format that fits many truck beds and off-road rigs.
- Company customer service is responsive, with one owner receiving a refund for a failed sender without hassle.
Sender swap needed
- The fuel pick-up tube can cause prime loss after ~20 seconds, requiring modification for consistent fuel transfer.
- Fuel sending units are unreliable — several reviewers point out failure immediately or within a short period.
Best for durability: you are building an off-road rig that needs a tough, proven 19-gallon tank and you are comfortable replacing the sender and pick-up tube.
Skip for plug and play: you want a turn-key fuel system that includes a working sending unit and pick-up from the start.
9. Universal 20 Gallon 80L Fuel Cell Tank Polished Aluminum Silver with Cap/Level Sender/12FT Oil Feed Line
A 20-gallon cell that comes with the fuel line kit, so you do not have to hunt for AN fittings separately.
This Edicapo 20-gallon fuel cell is built for the builder who wants everything in one box. The tank itself is polished aluminum with a 20-gallon / 80-liter capacity, dual 10AN outlets, and dual 10AN vent outlets. The real differentiator is the included 12-foot nylon braided 6AN fuel line kit with four different adapter angles — two 90-degree, two 45-degree, two straight, and two 6AN-to-10AN adapters. Owners consistently praise the welding quality and the selection of fittings, calling it well worth the price and noting that installation is as easy as you make it. One owner put it in a Studebaker and found the timing and fit perfect.
The one catch that keeps coming up is the anti-slosh foam inside. Several shoppers say that the foam broke down over time, disintegrating into small particles that clogged fuel filters and carburetors. Once they removed and cleaned the foam, all issues stopped — so if you buy this tank, consider removing the foam before installation, especially for a street car or generator that will not see aggressive cornering. Aside from that, the welds, the fittings, and the overall value are rated very highly by buyers.
Polished 20 gallon: This is the best value for someone who wants a complete fuel cell kit with quality fittings, good welds, and a polished look — just pre-emptively pull the anti-slosh foam to avoid filter clogs down the road.
Best for show cars: you want one purchase that includes the tank, cap, sender, and a full set of AN fittings and fuel line.
Skip for hidden install: you plan to use the anti-slosh foam — expect to remove it unless your build needs foam for aggressive cornering.
10. Better Built Steel Transfer Fuel Tank – 36-Gallon, Rectangular, Black, Model Number 29211584
A steel 36-gallon tank built for diesel work trucks that need a lockable, baffled transfer tank.
The Better Built tank is a different animal from the aluminum cells on this list — it is a steel transfer tank designed specifically for diesel fuel. It holds 36 gallons in a rectangular, gloss-black steel body with built-in baffles that add structural strength and prevent fuel from sloshing around during transport. The 2-inch diameter flush-mounted inlet and outlet bungs allow fast gravity-fed or pump-assisted flow, and the lockable cap adds real security on a job site. Owners praise the compact footprint that saves bed space, and many report it bolts on and fills without leaks.
The biggest caution centers on quality control and packaging. Nearly two dozen reviewers mention durability issues, specifically bent mounting tabs and dented fill caps that arrived from poor shipping protection. A few owners found welding debris inside the tank and weld spatter clogging the ports, requiring a 2-inch NPT tap clean-up.
36 gallon steel tank
- Built-in baffles add structural strength and minimize fuel slosh during transport — a real safety and stability benefit.
- 36-gallon capacity with 2-inch flush-mounted bungs for fast flow, plus a lockable cap for theft prevention.
- Compact design fits most truck beds without taking up the entire floor, leaving room for a toolbox.
Heavy and bulky
- Shipping damage is common — bent tabs and dented caps are reported by many owners, requiring straightening with a hammer.
- Welding debris inside the tank and ports is a recurring quality control issue that requires cleanup before first use.
Best for long hauls: you need a lockable, baffled, steel transfer tank for diesel in a work truck and can handle minor straightening and internal cleanup.
Skip for small trucks: you want a gasoline-rated tank or a polished finish — this is a rough-and-tough steel unit.
11. RDS MFG INC 71783 Auxiliary Fuel Tank 63Gal Wedge
A 63-gallon wedge that pushes a diesel pickup to roughly 1,000 miles of towing range.
This is the ultimate range-extender for heavy-duty diesel trucks. The RDS wedge tank adds 63 gallons of diesel capacity on top of your factory tank, bringing the total to around 87 gallons — enough for roughly 1,000 miles of towing, according to one owner. The wedge shape is designed to fit between the wheel wells and against the cab of a pickup, with a low profile that sits flush with the bed rails on many trucks. The tank is made from a single sheet of aluminum with welded top and side ends, minimizing potential failure points. Owners of 2015 Ram 3500 and 2007 Ford F350 trucks report a perfect fit, with the filler cap and vent protruding only about 2.5 inches above the bed, making it nearly invisible from the driver’s seat.
Installation is genuinely DIY-friendly. Several owners completed it solo in three hours — and one owner said it could have been 1.5 hours if not for cleaning out grime first. The included spring bolts and rubber friction strip prevent damage from vibration and movement. The single-sheet aluminum construction keeps the weight manageable for one person to handle before filling. The locking cap comes with two keys, and the tank includes a vent tube and fuel dispensing setup.
63 gallon wedge
- 63 gallons of extra capacity pushes total range to roughly ~1,000 miles — ideal for cross-country towing.
- Single-sheet aluminum construction with welded ends is inherently durable and leak-resistant.
- DIY install in about 3 hours solo, with all hardware included and a perfect fit on Ram 3500 and Ford F350 trucks.
Massive size
- Designed strictly for diesel fuel — not compatible with gasoline, so check your fuel type before buying.
Best for diesel trucks: you tow a fifth wheel across long distances with a diesel pickup and want to go 1,000 miles between fuel stops.
Skip for gas engines: your truck runs on gasoline or you do not need the absolute maximum range available in a wedge tank.
Understanding the Specs
Capacity vs. Usable Capacity
The number on the label is rarely the number you can actually use. Some tanks, particularly lower-budget universal cells, have internal pickup tubes that sit above the bottom of the tank, leaving 1–2 gallons of fuel you cannot draw. Anti-slosh foam, while helpful for fuel delivery during cornering, also occupies physical volume. Always measure your actual usable capacity by filling the tank and noting how much drains before the pickup loses prime.
Level Sender Ohm Range
Most aftermarket fuel cells include a sender rated at 0–90 ohms or 3–90 ohms. A 0–90 ohm sender sends a signal of 0 ohms when the tank is empty and 90 ohms when full. The 3–90 ohm variety starts at 3 ohms at empty. These are not interchangeable — your gauge cluster or aftermarket gauge must match the sender’s range. If the sender fails, you can replace it with a universal model from brands like Tanks.Inc, but verify the ohm range before buying.
FAQ
Can I plumb two auxiliary tanks together for more capacity?
What is the difference between a transfer tank and a fuel cell?
How do I know if an auxiliary tank will fit my truck bed?
Can I use a fuel cell designed for gasoline with diesel fuel?
What is anti-slosh foam and do I need it?
How accurate is the fuel level sender that comes with these tanks?
How long does it take to install a bed-mounted auxiliary tank?
What is the difference between 8AN and 10AN hose fittings?
Are auxiliary fuel tanks legal for street use?
How do I safely clean welding debris out of a new auxiliary tank?
Final Thoughts: The Verdict
For most people, the auxiliary petrol tank winner is the RDS MFG INC 45-Gallon Rectangular Tank because it offers a 45-gallon capacity, rust-proof fully welded aluminum construction, and an install that owners regularly complete in under two hours on full-size trucks. If you want a compact fuel cell for a street car or generator build, the 20-Gallon Fuel Cell Parts-Diyer gives you flexible dual 10AN outlets and anti-slosh foam at a value price. And for maximum diesel towing range, the RDS 63-Gallon Wedge Tank is the one to reach for — adding enough fuel for roughly 1,000 miles of towing between stops.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of July 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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