How to Inflate Dual RV Tires – The Easy Way

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Adding air to your RV’s tires should be straight forward but when you are faced with dual tires, also known as dually tires or duallies, it can seem a little more complicated. There are a few different ways that you can go about adding air to your dual RV tires, and the best one is going to be the one that you are most comfortable with but some ways are definitely easier than others.

To inflate dually tires, access the inner valve stem (with or without an extender), attach the chuck to the valve stem and use an air compressor with a high PSI rating to fill the tires.

RV tires are expensive, and nothing puts a damper on a trip like a blowout. Properly inflating your RV’s tires is going to help extend the life of your tires and keep your trip rolling smoothly. I’ve got a couple of tips and tricks that will make the process of properly inflating your duallies easier.

Ways to Add Air to Dually Tires

Adding air to the outside tire is easy – you just remove the stem cap, attach the air hose and chuck to the valve stem, fill the tire while checking the pressure, then replace the stem cap. Inflating the inside tire is when it gets fun.

One of the biggest challenges that comes with filling dually tires is accessing the inner wheel’s valve stem. If your dual rims are properly aligned then you won’t have as much trouble reaching it. If you’re like 99% of RV owners, your dual rims won’t seem to be properly aligned.

You can fix this by taking off the outside tire to reposition it so that the inner valve stem comes through the cutouts in the rim. Once your inner valve stem is at least accessible you’ll be able to fill it in the future without taking off the outside tire.

You can either use a personal air compressor or an air pump at a gas station, truck stop, etc to fill your tires, but if you do decide to use your air compressor you have to make sure it has a high enough PSI to get the job done. Dually tires typically should be filled to 80 PSI, and not all air compressors will be able to reach that pressure.

To use your compressor you’ll want to get a pressure gauge that’s long enough to reach the valve stem, which means you’ll need about a 12-inch hose without a valve stem extension installed.

The pressure gauge will let you keep an eye on the tire’s PSI as you’re filling to make sure that it doesn’t get under- or overinflated. You can monitor the pressure by just placing the pressure gauge onto the valve stem without pumping any air into the tire. 

If a tire is under-filled it will cause more wear and tear on the tire, not to mention it can make your RV more prone to tipping over which is definitely something you do not want to deal with. If your tire is overfilled, you increase the likelihood of a blowout and you also decrease your tire’s lifespan.

In order to fill the tire, you can try using an angled inflator chuck to better reach the valve stem and you can also find them in different lengths. It may take some playing around with different chucks to find the one that works best for your RV. You can also try getting a valve stem extension with different angles like 90 degrees, 120 degrees, etc.

Once you have your air compressor hooked up, squeeze the trigger/lever on the compressor hose to pump air into the tire and release the lever to see what the tire’s current PSI is. 

Use a Tire Stem Extension

A valve stem extender is exactly what it sounds like – a part that you can install to extend the length of your valve stem. Most of them are made of stainless steel and they attach directly to the tire stem, and you can leave them installed so that you’re all set for next time.

Sounds great, right? No more cramped spaces, no more fumbling for the valve stem, no more hassle. 

While that may sound like the best thing in the universe (especially if you’re already an hour into trying to check your dually tire pressures), most RV forums are actually pretty divided on how well they work and especially how safe they are for your RV.

Some people argue that they’re just as hard if not harder to install than just putting the chuck on the stem, and other people have had bad experiences with them leaking if left on for long periods. Still other people have reported the inside of the valve stem, which is rubber, deteriorating despite the stainless steel exterior. 

On the other side of the coin many people swear by them, saying they have never had a problem and their valve stem extenders make the dually filling process so much easier. 

Some newer and higher-end RVs will come with extenders already installed, which is awesome. If that’s the case then you can use them until you have to replace the tires and then look at replacing the extenders at the same time.

There are many valve extender kits that have good reviews and are recommended on the RV forums, but everyone seems to agree that you should avoid the airless stem extenders. One person reported losing two perfectly good tires in less than a year thanks to leaks from the airless extenders.

Tire Pressure Equalization System 

This is an equalizing valve that allows air to flow freely from one tire to the other, allowing both tires to be at equal pressure. I know what you’re thinking – I just checked the tire pressures and they’re both the same. Why would I need something like this? 

While the tires will be at the same pressure after you fill them, on the road is a different story. The inside tire is going to heat up more due to lower airflow and the in-board brakes, and this higher temperature is going to cause the pressure in your inside tire to rise as you travel.

As I mentioned, too-high of pressure can leave you prone to a blowout and put more wear on your tire, so the tire equalization valve seeks to remove that risk. 

Products like the Crossfire Dual Tire Pressure Equalization System show you if your tires are properly inflated while allowing the higher pressure in the inside tire to equalize with the outside one. This will add to your tires’ overall life expectancy and hopefully save you money in the long run.

Checking Your Dually Tire Pressure

Did you know that a tire being 20% under inflated will cause at least a 30% loss in the life expectancy of your tire? Similarly, a tire being 20% overinflated will cause at least a 10% loss in your tire’s life expectancy while increasing the risk of a dangerous situation. 

You should check your dually tire pressure before setting out on every trip, and when you fill up for gas while on your trips. It’s especially important to check if your RV has been sitting still for a while, as dry rot can cause leaks and other issues.

Generally, your RV’s dual tires should be at 80 PSI, and to check the pressure you’ll need to make sure the tire pressure gauge is rated high enough so that you get an accurate measurement. A pressure gauge that is too low will max out without telling you if you’re actually at 80, and one that is too high may not give you an accurate reading.

But before you go and just fill your tires to 80 psi you’ll want to check the owner’s manual of you RV or the placard stating the tire pressure rating for your RVs tires. You should also check on the tire itself what the rating is.

The rating found on the sidewall of the tire will actually state “maximum load-carrying capacity and the minimum air pressure required to carry this load”. This means it’s a good idea to know what your RV actually weighs for each axle when you are fully loaded for a trip, including all passengers.

Tire pressure should also be checked when cold. This is because when you start driving your tires warm up, increasing the air pressure in your tire. Any manufacturer rating from both the tire and RV will be for a cold tire.

Benefits of Tire Pressure Monitoring System

A tire pressure monitoring system is exactly what it sounds like – a way to monitor the air pressure of your tires in real time. This is done through the electronic system that sends periodic reports to the main console and will also alert you of any potential issues.

A sensor is mounted in each wheel or as part of your anti-lock braking system (depending on the model), and these sensors are what monitors your tire pressure,

These systems are fairly pricey up front, but they will save you a lot of money and time on the back end by allowing you to keep your tires inflated at the ideal pressure and therefore reducing the wear and tear on them.

Some monitoring systems will only track pressure while others will also give you information about temperature. The EEZTire-TPMS6 system will give you real-time updates about both while also providing audio and visual alerts to any problems, and it’s one of the highest-reviewed monitoring systems on the market.

Closing Thoughts 

Now you know how to inflate dual RV tires and why it’s important, and hopefully, you’ll be more confident the next time you get ready for a trip. Just remember to use a compressor with a high enough PSI, choose your valve stem extender wisely, and don’t be afraid to take the outside tire off in order to get the inner valve stem positioned where it’s supposed to be.

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