Why Air Down?
You air down tires off-road to get more traction and a smoother ride on loose or rough ground. Airing down means deliberately lowering your tire pressure before driving on unpaved ground. A softer tire spreads over more ground, which adds grip and smooths the ride. It is temporary: you air back up to your vehicle's recommended pressure before you return to pavement.
What does airing down do to a tire?
Airing down enlarges the tire's contact patch, the part of the tread touching the ground. BFGoodrich says it increases the footprint for better traction on soft or uneven terrain and gives a smoother ride over bumps and rocks (BFGoodrich off-road guide).
Staun's own FAQ gives the same two reasons: a larger traction footprint, and a softer tire that absorbs more shock on a rough trail. Both come from the tire flexing more, and that same flexing is the source of the risks below.
Which surfaces is airing down for?
Airing down is for loose or rough unpaved ground, such as sand and rocky trails. It is not for pavement. BFGoodrich calls it essential in sand, where a bigger footprint helps the vehicle float instead of sink (BFGoodrich).
On pavement the trade-off reverses. BFGoodrich says underinflated tires can reduce handling and traction, wear unevenly, and run hotter, which raises blowout risk.
How much should you air down?
There is no universal number. BFGoodrich says how much air to let out depends on your vehicle, your tires, and the surface. Other variables matter too, including tire type, vehicle type and weight, environmental conditions, and driver style and technique.
In the end, experiment to find what works for you and your unique mix of variables. Only your tire maker and vehicle maker issue instructions. Weight and tire size change the answer too.
What are the risks and limits of airing down?
Airing down has real trade-offs. Follow both your tire maker's and your vehicle maker's guidance, and keep these in mind:
- Load capacity is reduced at lower pressure.
- At very low pressure the tire bead can come off the rim. Staun's FAQ says lower PSI puts more stress on the bead, and that drivers running very low pressures typically install beadlock wheels. BFGoodrich warns that too little pressure can unseat the tire from the rim.
- Drive at lower speeds while aired down.
- Air back up before you return to pavement. BFGoodrich says tires aired down for off-road use must be reinflated before driving on paved roads.
- There is no universal safe minimum pressure.
How do you air down, step by step?
- Check your tires cold and compare the reading with the placard pressure.
- Choose a target that fits the surface, your load, and your tire maker's guidance.
- Release air. You can press the valve pin in short bursts and check a gauge, use a valve-core tool, or use automatic deflators.
- Confirm each tire with a gauge.
- Drive slowly, and take deflators off the valve stems before moving the vehicle. Leaving them on risks damage from external objects striking the deflator, which could damage the tire or the valve stem. Leaving them on at higher speeds will also likely leave the tire out of balance.
- Air back up before pavement.
What is an automatic tire deflator, and which Staun range fits?
An automatic tire deflator screws onto a valve stem and lets air out until the tire reaches a preset pressure. Staun Tyre Deflators, the Australian Original, has been making them in Queensland, Australia since 1998.
They come preset to a specific PSI, so you can use them at those pre-settings right out of the box. Or you can set your own target pressure within the range of use for that model of deflator.
Screw one deflator onto each valve stem, and each one stops releasing air automatically at the preset pressure dialed in on the deflator.
Staun's ranges are named for the pressure you air down to, not your starting pavement pressure. Pick the range that contains your target:
| Staun range | PSI range | Factory pre-set | Built for |
|---|---|---|---|
| Quickset | 6-30 PSI | Built-in gauge (no single pre-set) | Same use as Standard Range, but you read pressure at each valve as you set it |
| Standard Range | 6-30 PSI | 18 PSI | The original Staun set, made since 1998 |
| High Range (Heavy Duty) | 15-55 PSI | 35 PSI | Heavier vehicles and higher running pressures |
| Low Range (Light Duty) | 1-10 PSI | 7 PSI | Rock crawlers on beadlock wheels running very low trail pressure |
Staun deflators are sold through a network of distributors, in-store and online, such as Amazon.com. Find one on our Distributors page.
Frequently Asked Questions
What does airing down mean?
It means intentionally lowering tire pressure before driving on loose or rough unpaved ground, to gain traction and a softer ride. You raise the pressure again before returning to pavement.
Do I have to air down to go off-road?
No. It is a choice, and how much it helps depends on your vehicle, tires, and the surface. BFGoodrich says how much air to let out depends on all three.
Is airing down bad for my tires?
Operating tires outside of the manufacturer's recommendations is a trade-off between improved performance and the risk of damage to your tires. Damage does not always result. Most manufacturers do not publish off-pavement PSI recommendations because so many variables affect what constitutes a safe PSI. So airing down can be done safely without damage, but the risk exists. USTMA says underinflated tires generate excessive heat and stress, causing irregular wear and internal damage. However, those effects are more relevant to high-speed pavement driving than to the slow driving over rough surfaces that off-roaders typically do. Education is paramount when operating below the recommended PSI, because the risk shifts from the manufacturer to you as the vehicle operator.
Can I drive on pavement while aired down?
BFGoodrich says tires aired down for off-road use must be reinflated before driving on paved roads. Follow your tire maker's and vehicle maker's guidance. If you must drive on pavement, keep speeds as slow as practical and air up as soon as possible. The risk of damage is dramatically higher on pavement and at high speeds.
Do I need a special tool to air down?
Not necessarily, but the right tool makes the task much easier. Any method that lets air out works if you confirm the result with a gauge. Valve-core tools and automatic deflators change how much attention each tire needs, not the safety rules.