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Writer's pictureBen Easley
Jul 255 min read

Cheap and Easy: DIY 4-Tire Inflation System for Off-Roaders

Updated: Aug 21




You've probably seen it while out on the trail, someone has a bright colored hose connected to all four tires while airing up (or airing down). That certainly beats filling up a single tire at a time, especially for those of us with large volume tires (37"and bigger), where airing up can easily take 20+ minutes. Not only does a 4-tire hose system expedite the airing up process, the physics of the system ensure that all four of your tires are aired up to the same PSI. The system can also be used to deflate your tires, and just like airing up, the PSI will be equalized across all four tires.

This is the 4-tire inflation system we'll build in about an hour.

A little bit of work for BIG SAVINGS

My Ram 3500 has a 14 foot wheelbase, which requires more hose for mid-sized vehicles like a 4Runner or Jeep Rubicon. A 4-tire inflation system from one of the better known brands on the market would have been $250 for my long wheelbase truck. In about an hour's time, you can build your tire inflation system for a fraction of the cost. It cost me a grand total of $105 to build the tire inflation system shown in this article.



Parts Needed


Grand Total: $111


Tools

  • Blade, knife or pipe cutting tool

  • Crimp/cinch fastener for hose clamps >> $25 on Amazon


Getting To Work

Cutting the Air Hose

The first thing you need to do is determine how much hose you're going to need. For a 4-tire inflation system, there are a total of 6 pieces of hose (3 for each side) that you'll need to cut from the larger role of air hose. We recommend making a symmetrical system, where the 3 cuts of hose on one side, will match the three cuts of hose on the left side. Even if you have an onboard compressor that sits in an odd location (such as the side of the vehicle), you can always create a hose extension from the M plug to your air compressor. For this cut, you want to use the two ends of your air hose. This allows you to thread them into the 4-way brass connector.

For the sake of these build instructions, we'll assume the air compressor is sitting on the ground, directly in front of the vehicle. You'll want to measure (you can use a piece of string or rope) how far it is from this location to your tire. We recommend adding some additional 1.5' of slack to ensure you have hose to your wheel. To fill the front tires, you'll cut two, 3' pieces of hose. And lastly, you'll need to measure your wheelbase. Again, I like to add some extra slack. With my 14 foot wheelbase, I ended up using 16 feet of hose to run to the rear tires.


[draw a diagram of this hose setup] Assemble the Air Pressure Guage and Shut Off Valve

This next set of steps should only take a few minutes. Whenever threading any of these fittings together, always use pipe thread tape. First, take the air pressure guage and thread it into the 3-way brass fitting. On the bottom of the 4-way fitting, thread in the shut-off valve. Lastly, thread in the M-plug to the shut-off valve. You'll likely need to use a set of wrenches to get everything nice and tight.



Assembling the Hose System

Now we're ready to begin piecing our hose system together. At this point, you've already got a set of two hoses threaded into the 4-way brass fitting connected to your air pressure gauge. First, slide a cinch clamp over the air hose. Next, insert the T-shaped brass barb into the other end of the hose that's attached to the 4-way brass connector. Once you have the T-shaped barb all the way in, use your crimping tool to tighten the cinch clamp. Repeat the same steps for the other hose attached to the 4-way brass connector.

This is what your T-shaped barb should look like once installed.

Now we're going to attach the 3 hose from the T-shaped barb that will allow us to inflate our front tires. Referencing the photo above, we'll attach the hose to the valve that's point upwards. Follow the same process as before sliding on the cinch clamp first, and then working the air hose onto the brass barb. Once the air hose is snugly fit, tighten the cinch clamp. Repeat these steps for the hose on the opposite side of the vehicle.


Next, we'll install a brass barb into the other end of the 3 foot hose. Slip on the cinch clamp, insert the brass barb, and then tighten the cinch clamp. Thread on the locking air chuck onto the end of the brass barb (don't forget the pipe thread tape). Use a wrench if necessary to thread the chuck in so it's nice and tight. Repeat these steps for the hose on the opposite side.

The Rear Tires

Can you believe it? You're almost done! All we have left is the hose to the rear tires, which will repeat many of the same steps that we just did. Take the air hose that is meant to run from the front tire to the rear tire, slide on the cinch clamp first, and then push the hose onto the T-shaped barb. Tighten the cinch clamp. Move to the other end of the hose that will inflate the rear tire and install a brass barb, following the same steps as before (pipe thread tape, tighten the cinch clamp). Next, apply pipe thread tape, and install the locking air chuck. Repeat these steps for the hose on the other side of the vehicle and you're done!


Build an Extension

One of the nice things about the M plug is that it allows you to add an extension hose, or better yet, create a modular setup that allows you to plug into different air inflation systems. Imagine that your air compressor has failed, and you need to fill up at a gas station. If you build the appropriate parts on your extension hose, you can easily attach this to the air hose at a gas station! Here's the air hose that I built for my overlanding setup. My air compressor actually has an M plug on it, so I used a pair of M-style couplers. The hose features two brass barbs at each end, with the M-style couplers threaded on.










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