5th Gen Mods, Accessories, DIY, Install

Trailed “Spare” Tank Install For 5th Gen 4Runner

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Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Trailed 6-Gallon “Spare” Tank Overview & DIY Guide For the 5th Gen 4Runner

Traveling into the backcountry by vehicle can be a safe and rewarding adventure if properly prepared.

However, if you are not prepared things can turn into a post-apocalyptic movie scene, quickly. Liquid is essential for life, both for us and our rigs, having plenty of water and fuel will help ensure a safe return from any adventure.

That is where the Trailed “Spare” Tank comes in. These easily portable tanks will hold 6 Gallons of liquid in any place you can mount a spare tire. Notice that I said liquid and not just fuel tank.

Find it online

That is because the Trailed “Spare” Tank is constructed of Linear Low-Density Polyethylene which means it is food grade and can hold water as well as fuel. However, like any plastic container, once the fuel is added, it should no longer be used for potable water.

Size and Capacity

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

The tank is only 3 inches thick and 29 inches around and can be stacked together. To give you an idea of what this looks like, 3 tanks stacked together are the equivalent to the factory spare on the 4Runner. That is 18 gallons of fuel or water in what could be otherwise wasted space. Even more so, a BFG KO2 at 285/70 is around 12 inches adding another 6 gallons for a total of 24-gallon capacity.

If you have ever had to carry full jerry cans across a motor pool, then you know liquids are heavy. Exactly how heavy, well that depends on the type, and for some, the temperature (the colder fuel is the heavier it is)?

  • 1 gal of H2O = 8.34 lbs x 6 gal = 50.04 lbs + 10 lbs for the tank = 60.04 lbs
  • 1 gal of Regular Gas (87 Octane) weighs 6.216 lbs x 6 gal = 37.3 lbs + 10 lbs for the tank = 47.3 lbs
  • 1 gal of Premium Gas (91 Octane) weighs 6.35 lbs x 6 gal = 38.1 lbs + 10 lbs for the tank = 48.1 lbs

This can add up to a significant amount of weight depending on the requirements for the trip.

For me, the perfect set up for longer unsupported adventures would be at least 2 fuel and 1 water tank as the 4Runner is much thirstier than I am. This would equal 154.64 pounds. One of the main benefits of the Trailed “Spare” Tank system is that it keeps all of that additional weight low and improves the center of gravity versus having it on the roof.


Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Accessing gear when you need it is important and utilizing the factory spare hoist negates any additional mounting requirements. Using the OEM toolkit drop the spare tire.

Removing Spare Tire (DIY Guide)

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

If you have more than one spare tank, then stack them together. On the side, there are 2 nubs that correspond with 2 indents on the opposing side so they will lock into each other.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Reinsert the hoist into the center opening. Make sure to bend the tab that fits into the wheel stud hole flat, as it will cause damage. See below in the Durability section of this post. 

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Crank it up just like a spare. It keeps it tucked up out of the way and a single tank just disappears underneath the vehicle.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

I think 3 tanks are the ideal number as it keeps everything tucked under, but just keep in mind if you are doing any serious rock crawling you may want to drop down to 2.

Since I haven’t got my tire swing just yet, I attempted to place the tank above the spare to see how much clearance I would lose. Short answer… a lot, I would not recommend this… Ever.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

At the Trailed “Spare” Tank  12 o’clock is the recessed port to protect the cap. It uses a standard self-venting Scepter cap and nozzle, so it can easily be replaced if lost or broken.

At the 6 o’clock position is a flat base that allows it to stand up better. I would still lean it against something as it is still thin and heavy.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

There are 4 comfortable handles at the 45-degree marks, which allow multiple ways to carry and pour.

It also gives you additional tie-down points if needed. They remind me of some nice oversized plates from the gym.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Pouring fuel into a gas tank is never fun, no matter what type of container.

It is an awkward and messy process at best and that is why I have given up on pouring fuel. I have instead adopted the use of a siphon hose.

The one I use is an inexpensive shaker siphon hose as some of the ones with pumps leak after time and take up more room. It has a brass end with a little marble and spring that you shake in the fluid.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

It’s less strain and mess, as long as you have a zip lock bag to keep the hose in afterward. Or better yet let it sit out for a few minutes to let the fuel evaporate before bagging it.

I know that there will be the question of “What if you still want to carry a spare in the factory location?”. The Trailed “Spare” Tank can still be carried anywhere that a spare can be mounted. For the rooftop application, you can use something like the Front Runner spare wheel clamp to mount the tank.

If you are only using one or two tanks this will keep a very low profile. This would also be a great application for water storage as it could heat up in the sun, and be used for showers.


Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Another added benefit is that Trailed is made in the U.S.A., more specifically in Salem, Oregon.

So it’s supporting a local small business that is a part of the community. They also have a 5-year manufacturer warranty where they will replace or repair any defects. If things do go wrong that are environmentally induced (read, you smacked a rock with one), then they can be repaired using plastic welding.

If for some reason that it can’t be repaired it is fully recyclable, so it continues to be useful in another life.

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

These things are stout!

In a few hundred off-road miles it still looks new. However, since I only have one at this point and it is tucked way up it hadn’t been fully torture-tested. The largest damage sustained is when I forgot to bend down the tab that locks into the spare wheel stud hole and cranked it up far as it would go.

I really thought it would have punctured with near 50 pounds and all that force on a small metal edge but to my relief just a small dent.

Final Verdict

Trailed 6-Gallon "Spare" Tank Overview & DIY Guide For the 5th Gen 4Runner

Take my money! Initially, I was extremely interested in the concept but was unsure of the application. However, after putting it through the over 500 miles of backcountry trails it performed flawlessly.

I like my gear to be adaptable and durable and that is exactly what the Trailed “Spare” Tank is.

Comments or Questions? Leave them below!

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Nathan Moeder
Nathan Moeder
December 15, 2020 9:46 am

Can you elaborate on the durability? Meaning, do you have a lower the tank and “vent” them to release pressure when the climate changes? or is it a solid material like rotopax where you don’t have to worry about expansion and seepage? I want to get these but i don’t have to deal with venting. Thoughts?

Jeff Mann
Jeff Mann
June 16, 2020 6:38 pm

I looked into these. What I would like to see is some further refinement. If they made an add on kit that connected to a compressor to pressure the water out of a hose, or a 12 volt pump, and a way to fill it without actually going through the same routine as having a flat tire. I think its a great concept but could be better in function.

James Creech
James Creech
June 16, 2020 2:37 pm

I noticed on their website that these are not certified for fuel storage. I can see insurance issues if these are used for gas and something happens.

June 16, 2020 2:30 pm

I clicked because “KILL rotopax” headline in my email. I am one of the guys who thinks Rotopax are extremely overrated for both fuel and ESPECIALLY water. In fact, I controversially group them in with RTTs – looks cool, seems great, everyone wants ’em but in practice, expense, and functionally actually suck. I have a rather visceral hatred of rotopax after use (unless you trail ride motorcycles).
Anyway, this new kid on the block looks pretty cool and i love the market with great options. Thank you trail4runner!

June 3, 2020 7:03 am

I am wondering how good this would be for just using as weight in the winter. Living in Northern NY we get a lot of Lake effect, I’ve had trouble with finding a good spot for weights in the past 2 years. 3 of these stacked with water mixed with antifreeze would be good weight!

June 3, 2020 7:40 am
Reply to  Trevor Varney

180lbs that low with 3 tanks of that mixture would be a lot safer down low than the tractor weights I had loose in the back! My spare (LT285/70/17 only weighs 70-90lbs so that’s a good improvement. If you were loaded up for a trip it would be better to have the spare tire than the weight, but being my DD the weight in the winter would be super helpful!

August 7, 2020 6:42 pm
Reply to  Mike

Or use actual weights 45 plate and 35 plate ?

May 31, 2020 3:01 pm

I would rather have the spare tire exposed to rocks and ground impact than a fuel tank. Seems like a Jerry can mounted somewhere less exposed is a better solution.

May 31, 2020 11:00 am

I’m thinking move the tire to a swing out, and run two or three of these in the spare tire location.

May 31, 2020 11:12 am
Reply to  tcmault

Seems on their homepage they do indeed show multiple cans in that location.


May 31, 2020 10:35 am

This is pretty awesome!

Minh Nguyen
Minh Nguyen
May 31, 2020 4:14 am

Like how much ground clearance loss are we talking here?
This would be perfect if I could still keep my spare down there. Hoping the might come out with a “slim” version in the future.

June 16, 2020 2:56 pm
Reply to  Trevor Varney

it would be much lower in capacity, but it seems like one could be designed that fit entirely within the spare wheel — i’d get one if that was the case (no loss of ground clearance)

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