Dropping tyre pressures is the cheapest performance upgrade in four wheel driving, and the one most people either do badly or skip. Letting air out lengthens the tyre's footprint, spreads the vehicle's weight over more ground, softens the ride and lets the tread wrap over rocks and ruts instead of bouncing off them. On soft sand it is the difference between floating across and digging yourself a hole.
The kit is simple: something to let air out quickly, something to put it back in, a gauge you trust, and a way to fix the puncture you will eventually get.
Pressures by surface, as a starting point
Every vehicle, load and tyre combination is different, so treat these as the starting point we would give you over the counter rather than gospel.
| Surface | Typical pressure |
|---|---|
| Highway, loaded touring | Placard pressure, often 36 to 42 psi rear |
| Gravel and dirt roads | 28 to 32 psi |
| Rocky tracks | 20 to 26 psi |
| Mud and ruts | 18 to 24 psi |
| Soft sand and beach | 15 to 18 psi |
| Bogged in sand, last resort | 12 to 14 psi, and drive gently |
Two rules go with that table. Drop your speed as you drop your pressure, because low pressure plus speed is how tyres roll off rims and sidewalls get destroyed. And air back up before you get back on the bitumen, at the track exit, not at the next town.
For highway pressures, use the four psi check. Set your pressures cold, drive for an hour at highway speed, then check again. A rise of about four psi means you are close to right. Much more and the tyre is underinflated for the load. Much less and it is over.
Deflators: two minutes or twenty
Letting air out with a key or a stick works, and it is miserable, especially with a queue of cars waiting at the beach access track. Proper deflators do it quickly and evenly.
Screw-on automatic deflators go on all four valves at once and stop at a preset pressure while you stand back. They suit a group airing down together, and anyone who wants to set it and forget it.
Rapid deflators pull the valve core to dump air fast, then read the pressure on a built-in gauge. They are the quickest single-tyre tool going, and the pick for people who air down and up several times a day.
Whichever you use, check with a separate gauge. Built-in gauges vary, and the pressure that matters is the one actually in the tyre.
Choosing a compressor
This is where people underbuy and then regret it. The two specifications that count are free air delivery, usually quoted in litres per minute, and duty cycle, which is how long the compressor can run before it needs to cool down.
Small portable units are fine for topping up and the odd beach trip with one vehicle. Expect a slow refill and a very hot compressor.
A quality single-motor compressor is the sweet spot for most tourers. It will take four tyres from 18 psi back to 38 psi in a reasonable stretch, with a duty cycle that survives doing it twice in a day.
Twin-motor and permanently mounted units move serious air. They suit big tyres, group trips, and anyone running air lockers or air tools, and they mount under the bonnet or in a canopy out of the weather.
Look for a hose long enough to reach all four corners without moving the vehicle, a sealed housing if it lives in a drawer, and an inline filter if it lives in the dust. Our touring and camping range carries portable and twin compressor kits along with four-hose deflator systems, and we size a compressor to your tyres rather than to the price sticker.
Puncture repair kits
On a corrugated road the puncture is a matter of when, not if, and a tyre repair kit is what turns it into a twenty-minute stop instead of the end of the day.
A good kit has a T-handle reamer and insertion tool with solid handles, a decent supply of plugs, a knife, spare valve cores and a core tool, and a pair of long-nose pliers for pulling out whatever caused the hole. Plugs fix tread punctures from outside without taking the tyre off the rim, and with a compressor on board you are back on your way once the plug has seated. They are not a fix for sidewall damage. A cut sidewall means fitting the spare, and it is a good reason to carry two spares on remote trips.
Practise once at home before you need it. Forcing the first plug into a tyre by torchlight is a hard way to learn.
The rest of the kit worth carrying
Valve caps and spare valve cores weigh nothing. A pressure gauge should live in the console, not in the shed at home. For getting unstuck, recovery boards, winch rope and the rest of the gear sit in our recovery equipment range, and our 4WD recovery kit checklist covers what belongs in the back before a trip.
Frequently asked questions
What tyre pressure should I run on sand?
Start at 15 to 18 psi. Drop to 12 to 14 only if you are struggling, and keep your speed and steering inputs gentle at those pressures.
Which tyre deflators are best?
Automatic screw-on deflators suit people airing down a whole vehicle at once. Rapid core-removal deflators suit people doing it repeatedly who want speed. Both beat a stick.
What is the best car tyre puncture repair kit?
One with solid T-handle tools, plenty of plugs, spare valve cores and a core tool. Pair it with a compressor that can reinflate a full tyre, because a plug is only half the job.
How long should it take to air back up?
A quality single-motor compressor should refill four tyres from 18 psi to 38 psi in about the time it takes to have a coffee. If yours takes far longer, it is undersized for your tyres.
Want a compressor and deflator setup matched to your tyres? Call 1300 856 888, drop into the Brookvale showroom, or send us your vehicle and tyre size and we will put the right kit together.
