When it comes to airing down your tires, there are three primary ways available depending on your budget:
MANUAL AIRING DOWN
This is the most basic and least expensive method of blowing down your tires. Manually airing down your tires with these methods is time intensive, taking an average of 4-6 minutes per tire to discharge enough air to reach your goal tire pressure. You only need a tire pressure gauge. If you're using a standard sliding tire gauge, you can use the nodule on the back to depress the Schrader valve at the end of the tire stem and allow air to escape, pausing to recheck pressure and being careful not to go below your goal tire pressure.
Another simpler manual method is to use a tire pressure gauge with a dial that attaches directly to the valve stem and includes a button to release pressure. Regularly pause and release the button to allow the gauge to reflect the current tire air pressure.
TIRE DEFLATION TOOL
Using a tire deflation tool accelerates the off-road airing down procedure far faster
The tire deflation tool physically removes the valve core, the mechanism in the Schrader valve that keeps air from leaving and stores it within to keep it clean while enabling air to exit freely via the valve stem. Simply stop the air flow regularly to observe the gauge and stop when the desired pressure is reached.
AUTOMATIC TIRE DEFLATORS
The most convenient way to air down tires is to use automatic tire deflators. They can be adjusted to a preset PSI, attached directly to the Schrader valves on each tire, and then you simply pull the pin and the automatic tire deflator will air down the tires to the preset pressure and then stop.
They are more expensive, but they take up significantly less room than most other airing down tools.