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When we bought our first Class A motorhome, a portable air compressor was not on our list of essential RV must-haves, but we quickly learned how essential an air compressor is for RV tires. If you’re thinking “I don’t need an air compressor, I’ll just use one at the gas station.” Think again!
Gas station air compressors are designed for car tires which need around 35 psi (pounds per square inch) of pressure. RV tires on the other hand can have max pressures from 80 to 135 psi or more! Yes, even those small camper vans have LT (light truck) tires that are rated at 80 psi.
Imagine our surprise the first time we went to inflate the tires on our Class A motorhome at a gas station only to find out we were losing pressure! After that experience, we decided to invest in a quality portable air compressor for RV tires.
But portable air compressors can be used for many other things, including winterizing your camper, which I’ll explain how to do in this article.
Don’t have time to read the entire post on the best portable air compressor for RV tires? This is the portable air compressor we own and love. VIAIR makes different models, which I will get to later in this article.
What is a Portable Air Compressor?
Portable Air Compressors are smaller versions of the air compressors you might find in an automotive or other type of shop. The compressors will have an electric motor and a large holding tank of compressed air. As the air is used and the pressure drops below a certain point, the electric motor turns on and refills the tank.
The portable version of these compressors come in many different styles. For the purpose of this article, I’ll be discussing 12 volt portable air compressors. These are meant to travel with you and run off of your car/RV battery or 12v outlet (aka cigarette lighter) in your car. Some are made for smaller car tires while others have the ability to work on everything up to and including semi-truck tires.
Another type of portable air compressor is a scaled down version of their larger counterparts and plug into a standard 120 volt household outlet. These tend to be used on smaller construction jobs where you need something small and portable. They will run air tools, paint sprayers and other types of tools you’d find on a construction site or in your garage that require compressed air. These portable air compressors can also be used to fill up vehicle tires.
However, I wouldn’t recommend the 120 volt air compressors for RV tires. They are larger and heavier than the 12 volt portable air compressors plus they require that you plug in to a standard 120 volt outlet. While most RVs have these, you may not have a large enough inverter or big enough battery bank to run it. It also doesn’t do you any good if you want to bring it along in your toad (towed vehicle) for an off-roading adventure where you’ll need to air your tires back up.
Table of Contents
Benefits of a Portable Air Compressor
1. Ability to Air Up Your RV’s Tires Anywhere
Before we took off on our first trip in our Class A motorhome, I made sure to check the air pressure for all six of our tires. Our tire pressure was low all around but it was good enough to drive to the nearest gas station to fill up. When we pulled into the gas station, I dropped four quarters into the air compressor and began filling up one of the front RV tires. After a couple minutes, I checked the tire pressure again and saw that it had actually LOST 5 psi! We then looked for a truck stop to go fill up at but, low and behold, there were none where we were going.
While some truck stops will have air compressors able to air up larger tires, they are not always available. An under-inflated tire can be dangerous and lead to a blow out, so being able to air up your tires whenever you need to is essential.
Having an air compressor with you allows you to make in-field tire repairs such as a puncture or tear. While we haven’t had to make a repair in the field, we’ve been a number of places where we were no where near civilization and the nearest repair shop was hours away…or we didn’t have cell service to call for help.
When we had our Jeep, we had to use the spare tire multiple times and guess what? When I put the spare on and lowered the vehicle, I found that the tire pressure was very low. A few minutes later, I had our air compressor out and the tire back up to the correct pressure.
We’ve also been able to help other people on the road who needed to air their tires up but didn’t have a compressor with them.
2. You Can Take It With You
As the name implies, these 12 volt air compressors are portable. The VIAIR air compressors come in durable canvas carry bags and are light enough for most people to carry (the 450P-RVS is the largest model and weighs in at 13 lbs).
When we towed a Jeep Wrangler behind our motorhome, we would take our portable air compressor with us when we went off-roading. This allowed us to air the tires down on the trail and then, when we got back to the pavement, we aired our tires back up. This is where the 12 volt air compressors shine over the 120 volt versions because we didn’t have a way to plug-in a 120 volt air compressor in the Jeep.
I also prefer the portable air compressors over on-board air compressors that are permanently mounted to the vehicle because if you sell the vehicle or need the compressor in a different vehicle, the portable compressor can go where you do.
3. There are Multiple Uses for a Portable Air Compressor
Beyond just inflating tires, a portable air compressor is very handy when camping. You can use them to inflate inflatable kayaks, paddle boards, balls and many other things you might bring on your next adventure. When the weather gets below freezing, we’ve used ours to winterize our camper. I’ll explain how to do this below.
Portable Air Compressor Features
Because there is such a wide variety of portable air compressors, I won’t be able to cover all of the different features but I will try to cover some of the most common ones you should be aware of.
1. Max Working Pressure, CFM, Duty Cycle and More
Pay close attention to the specifications when shopping for a portable air compressor. Max working pressure was important for us when we were shopping. Our RV tires at the time had a max cold pressure of 110 psi, so we needed a compressor that had a max working pressure equal to or greater than that. We also wanted something that had a 100% duty cycle which means it can run continuously for an hour. An air compressor with a 33% duty cycle can only run for 20 minutes (33% of 60 minutes) and then it will need 40 minutes to cool between cycles.
Smaller 12v pumps that plug into a cigarette lighter (12v outlet) typically have a max working pressure of 60 psi and have a short duty cycle, 20 minutes @ 30 psi for example. This is perfect for airing up bicycle, motorcycle and car tires but can’t tackle even the smallest RV tire.
CFM is another specification which measures the cubic feet per minute of air flow. As the pressure in a tire increases, the CFM will drop because it’s taking more effort for the compressor to push the air into the tire. CFM will be an indication of how quickly you can air a tire up and whether the pump will be able to run air tools.
2. Accessories
Air Hose. Basic portable air compressors will typically come with an integrated air hose that’s 3-5 feet in length. Depending on how long the power cord is, you may not be able to reach your rear tires. Higher end air compressors will come with quick connect fittings and air hoses. This allows you to change out the air hoses if one becomes damaged or if you need a longer/shorter hose. Our 450P-RVS came with two 30 foot hoses so we’re able to reach up to 60 feet from the compressor! If we needed to extend even further, we could add a third hose.
Chucks. Standard, air compressors will come with either the bike pump or gas station style chuck. If the compressor has a quick connect fitting, you can change out the chuck depending on what you need. Our VIAIR came with a gas station style air inflation gun, 90 degree screw on chuck, 45 degree chuck (for reach the inner wheel on a dually) and multiple inflation tips. We can also add other accessories that use the quick connect fitting.
Carry bag. These are nice, especially if you have multiple accessories, to keep everything in one place.
3. Automatic Cut-Off
If you’ve ever used a gas station air compressor, you know that when it turns on, it keeps running until the time limit is up. Basic portable air compressors operate in the same way, they continue running until you turn it off. If the compressor has a short duty cycle, this may require you to run back and forth to turn it on and off every time you switch tires.
Portable air compressors with an automatic shut off typically have a small holding tank. When you first turn the compressor on, it will run, filling up that tank. Once the tank reaches pressure, the compressor will shut off until you begin filling a tire with air. Once you’re done filling up the tire and the tank pressurizes, the pump will automatically shut off.
4. In-Line Pressure Gauge
I think an inline pressure gauge is an essential accessory to have. Ours has one build into the gas station style inflation gun and it allows us to see what the tire pressure is without having to remove the chuck and check the pressure with a separate gauge.
Downsides of a Portable Air Compressor
The downside of 12v portable air compressors is that most are not designed to run air tools. The problem is that they can’t provide a high enough CFM that an air tool requires. Some compressors have small holding tanks which will give a quick burst of air when you first pull the trigger on a tool and allow it to run for a second or two but not much after that.
If you want or need to run air tools on the road, my suggestion would be to look at 120v portable compressors that have a larger holding tank.
Our Experience with Portable Air Compressors
Many years ago, I had a couple inexpensive portable air compressors that I kept in the garage for those odd times I needed to pump up a tire. Inevitably, they would work a couple times and then quit working. While they were cheap to replace, I didn’t want to keep throwing my money away and resigned myself to drive to the gas station and fill up there.
When we got the VIAIR I was skeptical at first, especially given the price, but I’ve since learned to rely on them. When we first got it, we mainly used it to air up our RV tires. With our overland 4×4 truck camper, we would use it on a regular basis to air our tires back up from being on an off-road trail or just fill up the tires as needed. We also began using it for things like blowing out our water lines, helping friends or using it to blow the dust out of an air filter.
We have 34” tires on our truck and when we’ve taken it off-roading, we’ll air down the tires to around 25 psi. When we air the tires back up to 65 psi, it takes approximately 6 minutes per tire.
We’ve used ours in all sorts of conditions like in the middle of the desert in 90 degree heat with blowing sand and never once had an issue.
Why the VIAIR 450P-RVS is the Best Portable Air Compressor for RV Tires
In short, because it works for all RV tires from small Class Bs all the way up to large Class A motorhomes. With a reach of 60 feet, you’ll be able to reach those rear tires on a 45 foot Class A or a pull behind camper.
The air compressor and all of its accessories fit in the included heavy duty carrying bag and it’s small enough to fit in most storage bays or cabinets.
With the standard quick connect fittings, it allows you to purchase additional hoses and other chucks or air guns to suit your needs. We got a blow gun for air compressor that works well on blowing dust and other things out of an air filter.
While the VIAIR air compressors come with a 1 year warranty, we’ve not needed to use it.
It’s robust! After filling up the tires in our truck one day, I was distracted and forgot to put the compressor away. As I started driving away, I drove over something and when I got out, I saw that I had driven OVER our compressor! Come to find that while I’d bent the feet of the compressor and the alligator clips that attach to the car battery, everything else was fine. I spent a few minutes bending things back into shape and the compressor has been running fine ever since.
Which VIAIR Portable Air Compressor is Right for Your RV Tires?
VIAIR has a number of portable air compressors. The VIAIR RVS series of portable air compressors are specifically made for RVs, both motorized and towables.
Class A motorhomes – VIAIR 450P-RVS
Class C motorhomes, truck campers and large towables – VIAIR 400P-RVS
Smaller Towables – VIAIR 300P-RVS
Class B motorhomes and camper vans – VIAIR 89P-RVS
If you also plan to use your portable air compressor for your Jeep or off-road vehicle, the VIAIR 400P is recommended.
Again, my pick would still be the VIAIR 450P-RVS because it can do everything except run air tools.
What Other Options are There for Portable Air Compressors?
The list is nearly endless for the different makes and types of portable air compressors for RV tires. If I was going to buy something besides the VIAIR, I would look for something from a well established brand that’s been used by off-roaders. I say that because people who use an air compressor off-road, tend to use them more often and in harsh environments. The compressors not only have to withstand the environment but they need to be robust enough to be bounced around in a vehicle for hours on end and work every time. In the backcountry, away from cell signals and paved roads, your life may depend on your tools, which includes your air compressor.
My first choice would be the ARB High Performance Portable Air Compressor. Many off-roaders will install these on-board their vehicles but this model comes with in a hard carrying case so that it’s portable. The price is on-par with the VIAIR but lacks some of the accessories that are standard with the VIAIR. The ARB is also has a higher CFM than the VIAIR and is rated to run air tools with an optional 1 gallon air tank.
If you want something larger to run air tools, my suggestion would be a pancake style portable air compressor. They’re called “pancake” because of the pancake shaped air tank located below the compressor. They’re all 120v so you’ll either need an inverter and battery bank that is large enough to run this style of compressor from your RV or be parked somewhere like a campground where you have access to an outlet. While larger and heavier than a 12v portable air compressor, pancake style compressors like this Craftsman are about a third of the price of the VIAIR or ARB.
Finally, if you are on a budget and don’t plan to be out in the backcountry, I would suggest searching Amazon for “12v portable air compressor” and finding one in your price range that has good reviews and the features you need in a portable air compressor.
What is the correct tire pressure(s) for your RV?
The correct tire pressure for your RV tires is going to vary based upon the the weight of the vehicle and whether you have single or dual rear wheels. For example, on our truck camper, the tires at the max cold pressure of 80 psi are load rated for 4,050 pounds. Before you can determine what the correct tire pressure is, you need to weigh your RV. This can be done at any truck stop that has a CAT scale. Simply drive up onto the scale and follow the directions. They’ll provide you with front, rear and trailer axle weights. With this information you can look up the inflation chart for your tires and determine what the correct tire pressure is. Here’s an example of Truck Tire Load Inflation Tables from Bridgestone. https://commercial.bridgestone.com/content/dam/bcs-sites/bridgestone-ex/products/Databooks/TBR/Bridgestone-TBR-Load-And-Inflation-Tables-08-08-2018.pdf
Correct tire psi, especially on lager motorhomes is a critical safety item. If your tires are under inflated, that can cause excessive heat, wear and eventually a blow out. We’ve had friends in larger Class A motorhomes experience a blow out and in one case they lost complete control and totaled the RV and in the other, while they lost some control, they were in an area with a wide shoulder and were able to safely stop. Under/over inflation will also cause excessive wear on your tires and RV tires aren’t cheap!
One way to help prevent tire blow-outs and monitor your tire pressure is by installing a TPMS (tire pressure monitoring system) for your RV. Many new cars come with these now but many RVs still do not. They are easy to install and monitors like the TST or TireView come with 4-12 sensors depending on how many tires you need to monitor. Here is a link to the TST Tire Pressure Monitoring System.
How to Inflate RV Tires
You should never stand next to an RV tire when you are inflating it. RV and truck tires can explode when being inflated and each year, people are killed and seriously injured by them. This is why, if you look in a truck tire shop, you’ll see steel cages where they set the tire before inflating it.
To begin inflating your RV tires, start your engine since the compressor will be running off your car battery (you don’t want to air up your tires only to find you’ve drained your battery). If your compressor has an on/off switch, set the switch to the off position. Insert the 12v plug into the vehicle’s 12v outlet or cigarette lighter or attach the black (ground) alligator clip to the vehicle – typically exposed metal like a bolt or nut on the side wall inside your engine bay. Check your vehicle’s owners manual to see where to attach the ground when jumping the vehicle if you are not sure. Next, attach the positive (red) clip to the positive terminal of your battery. When you’re ready to begin inflating your tires, turn the pump on if it’s not already and inflate each tire to the correct tire pressure. Make sure to stand away and off to the side of the tire.
Another reason I like the VIAIR 450P-RVS is that it comes with a 90 degree screw on chuck and dual hoses. To keep myself safe, when I am filling our tires, I attach the first hose to the air compressor, then I connect the air inflation gun between the first and second hose and the 90 degree twist on chuck will twist onto the end of the tire valve and then I can stand away from the tire (up to 30 feet) and safely fill the tire. The gauge on the tire inflation gun tells me when the tire has reached the correct pressure and then I can remove the chuck and move on to the next tire.
How to Winterize Your RV with a Portable Air Compressor
Many people are familiar with the pink RV anti-freeze that’s pumped through the water system of an RV to winterize it. Personally, I’m not a fan of this stuff. I won’t get into all the reasons why but in short I much prefer to blow the water out of my camper’s lines.
To do this, we used an air compressor and a blow out valve like this one.
Disclaimer: The instructions below are how we winterized our truck camper and are meant to give you an idea of how it’s done using compressed air. These are not instructions on how to winterize your RV. Every RV is different. If not done correctly, compressed air could damage water lines, water heaters, pumps, valves and other components of your water system. Be sure to read your owners manual and contact your RV manufacturer on the best process to winterize your RV.
- Drain all water from the camper’s fresh water tank, water heater, filters and low point drains. If there is a tankless water heater, make sure to drain the water out of it as well. On our camper, I’ve found that if I open the drain valve on our water heater and turn on the water pump, it quickly empties the fresh water tank.
- Turn on the water pump and open each hot/cold water valve (sinks/showers/toilets/etc) to clear out excessive water left in the lines.
- Install the blow out valve to the fresh water fill inlet and open the drain valve on the fresh water tank. Begin pumping air into the fresh water fill and there should be air/water coming out of the drain valve. If there isn’t, stop immediately. Continue until water is no longer coming out of the drain.
- Move the blow out valve from the fresh water fill inlet to the city water inlet. Open each water valve (sinks/showers/toilets/etc) one at a time and then blow air into the system. Have a person inside the RV monitoring each valve to ensure air/water are coming out. If it is not, stop immediately. Continue until no more water is coming out of the valve.
- Repeat Step 4 with each water valve, hot and cold. I also like to go back to the hot water heater and open up the valve there again and blow more air to ensure it’s completely empty as well as the fresh water tank.
- Finally, empty both grey and black holding tanks.
When freezing temps are over, simply refill the fresh water holding tank, turn on the water pump and open the appropriate valves to begin getting water back into the system.
Here is a video of how we winterize our camper van:
How to Repair a Flat Tire
While I would love to be able to explain how to repair a tire in the field in this article, it’s simply too in-depth. As you may have guessed however, one essential tool for repairing a tire in the field is an air compressor. The other is a high quality tire repair kit. The one we own is the Outback Extreme Ultimate Puncture Repair Kit. This is advertised to work on anything from ATVs to semi-truck tires.
A great resource to learn how to repair tires in the field is the book Raising Your 4WD Vehicle Off-Road & In-Field Tire Repair by Bob Wohlers. I took Bob’s class and have this book. It’s a wealth of knowledge and a must-have for anyone venturing off the beaten path.
Summary
A high quality portable air compressor for your RV tires can be an expensive purchase but, as we’ve found, it’s well worth the investment. While we’ve had nothing but good experiences with VIAIR, there are many other options out there. If you have portable air compressor you really like, let us know in the comments.
