How to inflate your tyres with a 12v air compressor

How to Deflate Your Tyres for Off-Roading

Any serious off-roader will tell you that different surfaces require different levels of inflation in your tyres for a safe and comfortable ride. The general recommendation for tyre pressure on most cars is anywhere from 30-35 PSI, with larger 4x4 tyres requiring up to 40 PSI. Specific information for your vehicle is usually located on the driver’s side door, under the bonnet, in the glove compartment, or in your owner’s manual.

This PSI is what is recommend for road driving, but for non-road surfaces like sand and mud, you’ll want to deflate your tyres to increase the surface area of the bottom of the tyres so that they have more purchase over the terrain.

If you’re going to be driving on gravel, you may want to bring your tyre pressure down to somewhere in the 25-28 PSI range. For mud and rocky terrain that you’ll need to slowly crawl over, you’ll likely want to take the pressure down again, to something like 20-25 PSI, and loose sand may require a PSI as low as 15-20 for easy traversal.

How Use a Tyre Deflator

The first thing you’ll want to do is pick up a good tyre deflator. Repco stocks a bunch of different deflators, many with digital displays and gauges that make determining the correct PSI for your tyre incredibly easy.

Connect the Deflator

Once you have figured out the correct PSI for the current terrain, thread the deflator’s spindle onto the tyre valve stem. Try to avoid cross-threading and over-tightening so you don’t damage the valve.

Open the Valve Core

Push the valve core armature in and turn it slowly clockwise so it connects with the valve core. Once you have engaged the core you can start to turn the armature section anticlockwise to release the valve core.

Slowly Release the Air

Check the air pressure of your tyre on the deflator’s gauge and release the tool’s air release valve back to begin releasing the air from your tyre. When you reach the correct air pressure, push the valve core armature back in, turn it counter-clockwise to press the valve core back in and then unwind the spindle, remove the deflator, and put the valve cap back on.

Make sure that your valve core is properly reseated when you are finished deflating the tyre, because if it’s loose, it could get shot out of the valve and your tyre will fully deflate —there’s no harm in bringing some extra valve cores along when you go off-roading to avoid any mishaps!

Inflating Your Tyres

There are lots of different ways to inflate car tyres, such as a foot pump, tyre inflator, portable 12v air compressor or a larger air compressor in your home garage. We’re going to go over how to use a 12v portable air compressor, as it’s one of the most convenient and simplest ways to inflate tyres and it’s perfect for camping and off-roading —the scenarios where you’ll be deflating and reinflating your tyres the most.

Check Your Tyre Pressure

If you’ve used a deflator to lower your PSI, then you’ll likely have a good idea of the pressure of your tyres, but if a tyre has become deflated via other means and you’re not sure of its exact pressure, you’ll want to get a dedicated pressure gauge to be sure.

Powering the Air Compressor

If you have a larger air compressor that requires power from your car’s battery, attach the positive alligator clip to the positive onto the positive terminal on the battery to start and then attach the negative clip to the negative terminal.

You’ll want to run the car’s engine while the compressor is on so that it doesn’t drain the battery too much —you can even toggle your idle up switch for some extra revs if you’re expecting a lot of drain on the battery.

For a larger 4x4 tyre you’ll want a 12v air compressor that can output at least 150LPM (5CFM) —unless you want to be standing around in the mud waiting for your tyre to pump up.

Repco offers a wide range of different 12v compressors, from light duty compressors and tyre inflators that plug into your 12v accessory port to something like the Maxi Trac 12v Heavy Duty Air Compressor Dual that’ll use your car battery to put out 300LPM and pump up a 4x4 tyre in less than two minutes.

Inflating the Tyre

Something to note is that the recommended tyre pressure given by manufacturers is for cold tyres, so if it’s a scorching hot day or you’ve been driving on your tyres a lot, you’ll want to wait until they cool off to inflate them.

Once your air compressor is connected to the battery, place it next to the tyre you want to inflate, then remove the valve cap and attach the hose. Make sure you have an air chuck attached to the end of the hose to allow it to connect properly to the tyre and if you’re using a larger air compressor, you’ll want a regulator to make sure your tyre doesn’t over-inflate.

If you’re using a regulator, connect the compressor hose to the regulator, and then attach it to the tyre valve with the chuck ­—you’ll need to set the regulator to the desired pressure before it starts releasing air, so it doesn’t exceed the PSI you want.

Now that you’re connected to the tyre, listen out for the hissing sound of air escaping, and if you hear it, just adjust the connection of the hose until it stops.

Monitor the PSI level of your tyre using the air gauge on your 12v air compressor or via a separate air gauge and once it reaches the correct PSI, switch off the compressor, carefully detach the hose from the tyre, and replace the valve cap.

Remember to double-check the pressure of your tyres before you hit the road again to make sure they’re at the correct PSI.

Get the Most Out of Your Air Compressor

Inflating car tyres is a fairly simple job with an air compressor and you’ve got a lot of options at Repco when it comes to portable 12v compressors, tyre inflators, or even larger belt-driven air compressors for your home garage or workshop. Pumping up tyres and pool toys isn’t all an air compressor is good for either, so be sure to check out our range of air tools and other accessories to get the best out of your system.