Deflating your tires to appropriate pressure for your terrain is the very first thing you should do before going off road.
Deflating tires increases traction, makes the ride smoother, and decreases chances of tire punctures.
In our business we air up and down up to 12 times a week.
The Staun auto style deflators (around $80) work with a spring mechanism to stop the deflation when the desired pressure is reached.
Each one must be set to the pressure by turning the barrel of the deflator, lengthening or shortening the spring, this adjusting the pressure where the deflator stops.
The theory is great, the reality is that the range is several psi – around 2 to 3. You can spin them on and leave, but the picky will be watching the pressure on the TPMS inside (if equipped).
The settings tend to be lost so it needs to be reset pretty frequently unfortunately.
With the ARB EZ Deflator ($40) you spin the mechanism onto the valve, then you remove the valve stem with the unit.
When you pull, the air is released and you see the pressure on the gauge.
It’s the fastest to air down with as the entire valve stem is removed. However, you do have to remain crouched next to the tire for the duration of each deflation. Accuracy is top notch.
The cheapest is the Teraflex keyring deflators at $16. All you do is spin all four on, then monitor the pressure with a tire gauge and remove when you reach the desired pressure. If you do not remove in time, there is no safety mechanism and you could potentially completely deflate your tire.
I like how you can walk away, keeping in mind you have to periodically monitor it. If all 4 tires start around the same pressure, all four will deflate at the same rate and will end up with very similar pressures.
Hopefully our experience can help you decide which style works best for you.
Between the three we use the Staun auto deflator on the Jeep with TPMS data displayed on the dash, and we use the Teraflex keychain on the Jeep that doesn’t display the pressure. The ARB is a quality product, but I don’t use it as often as the others.