Tire PSI.

Tire psi, the one thing that doesn't cost money but can get you further than any mod on its own.

The amount of psi in the 4x4 tires can be the difference between a great day out 4 wheel driving and a lot of digging which could turn into a recovery marathon.

Airing Down Your 4x4

Air Down To The Right psi.

Sand and Tire PSI:

On sand a tire inflated to normal highway/street pressures will sink and dig into soft sand instantly.

Highway tire pressures may be alright on hard packed sand but the second the wheels start spinning the vehicle will get bogged very quick.

Tires deflated to lower pressures will increase the foot print of the tyre itself, every 4 psi less will increase the foot print noticeably.

While deflating the tires with fast deflators you can actually see the tyre foot print growing by the second.

Most 4 wheel drives will find that a tire psi of about 14-18 is good enough for most soft sand driving, in some cases lower pressures may be required. The idea is to find the perfect pressure that allows the vehicle to float over the sand.

How low a tyre pressure can you go in sand?

Anything lower than 10 psi comes with a big risk of rolling the tyre of the rim, usually caused by turning at speed.

Sometimes there is no choice but to lower even down to 7 psi just to get out of a boggy situation, if this is the case, inflate the tire pressures back up to at least 10psi ASAP.

Only use low tire pressure for off roading, a low pressure on the highway is downright dangerous and will cause damage to the inside and outside of the tires.

Tire pressures on other off road surfaces.

Off roading and low tire pressures will assist majorly in traction and will prevent track damage, tyre damage and wear to the 4x4’s driveline.

The bigger the foot print the more traction there will be as more rubber surface is in contact with the terrain, this also makes it harder to spin the wheels which will prevent track damage.

The lower the psi the softer the tyre will be which means the ride/drive over any terrain will be more comfortable and less wear on the 4x4's suspension and vehicle itself. This is because low tire psi will allow the tire to mould around rocks, tree roots, sticks, logs, potholes and sharp objects.

Tires with too much pressure will just spin and/or puncture.

Off road tyre pressures will depend on the terrain in question, see terrain conquering for more detail.

Photos of a tyre at different psi.
Notice how the footprint increase in size:

Tire pressure foot print size 40psi

40 psi

Tire pressure foot print size 30psi

30 psi

Tire pressure foot print size 20psi

20 psi

Tire pressure foot print size 10psi

10 psi

Tire pressure foot print size 35psi

35 psi

Tire pressure foot print size 25psi

25 psi

Tire pressure foot print size 15psi

15 psi

Tire pressure foot print size 5psi

5 psi

Photos of a tyre on a rock at different psi.
Notice how the tyre moulds around the rock:

Tyre pressure rock 40psi

40 psi

Tyre pressure rock 30psi

30 psi

Tyre pressure rock 20psi

20 psi

Tyre pressure rock 10psi

10 psi

Tyre pressure rock 35psi

35 psi

Tyre pressure rock 25psi

25 psi

Tyre pressure rock 15psi

15 psi

Tyre pressure rock 5psi

5 psi

Tire psi and corrugated roads.

Badly corrugated roads can literally rattle a 4 wheel drive apart by loosening bolts, screws and other tie downs.

Reducing the tire pressures will help to soften the ride and reduce the rattling.

It is very noticeable how much of a difference it is to the vehicle and ride when combined with the right speed.

Tire Deflator:

This is an important item every 4 wheel driver should have, for more info on the different types of tire deflators see Tire Deflators.

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