Tyre pressure offroad, who does what?

I regularly let mine down to 10psi in soft sand [ TDI 130 on sunraysia rims ] front & rear.
I know there is a possible risk, so I drive accordingly until aired up a bit more.
Not a D2 , but never had a problem at that pressure .

A Disco2 will retain beads a lot better than most other rims because of the bead retainer behind the bead. They're awesome, unless you're a tyre fitter.

The pressure really depends on the size of tyre and the construction of tyre. I'm not recommending anything for you, but for me....

285/75-16 Goodyear MTR Kelvar - 10.5psi on sand

285/75-16 Goodyear MTR - 12psi on sand

285/75-16 Pirelli ATR - 15psi on sand.

33x10.5-16 Simex JT2 - 10.5psi on sand

34x11.5-16 Simex JT2 - 10.5psi on sand.

Here is the trick with sand pressures.... choose a footprint rather than a psi that you're after. Then you can set your tyre pressures with a bit more usability when trying to gain traction. An even pressure may end up giving you less traction at one end of the 4WD or be too soft at the other end.

So, for example as an extreme case, when airing down JT2's, we would look for a certain number of tread lugs on the ground to give an even footprint. When loaded, that might mean there is 10psi in the front and 12 psi in the rear to carry the extra weight. With Pirelli ATR's it may mean 14psi at the front and 16psi at the rear.

http://www.slunnie.com/coppermine/al...0001/07psi.JPG

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Originally Posted by gavinwibrow

Yep have rolled a tyre off in a D1 alloy while turning at about an unrealised 13 psi - so the question arises, do they have the same extra "retaining lip" as the D2?

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I havent seen how the Disco1 bead is retained, but in the bush they don't seem to retain like a D2, they're more like a normal offroad rim and far better than any road or Sunraysia type rim. I do note that 235/70-16 BFG AT tyres notably are a loose fit on those rims.

My default starting point for sand is 18 psi all round. For rocky and rough tracks between 22 and 25 psi and I keep my speed below 80 kph.

cheers

Steve

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Originally Posted by shayne86

Hi everyone.

Just curious, what pressures does everyone run when offroad?

More specifically, on the beach, does anyone maintain the same difference between front/rear when they air down? For example, 30psi front and 38psi rear (as recommended from factory) does anyone keep the 8psi difference when aired right down?

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Hey Shayne, I have a D4 with 19inch rims, I've done two fraser trips recently and have run 22 front/ 26 back which worked well both on the sand and rocks/ inland roads. I had two passengers and not a lot of gear onboard. Could definitely run lower if only on sand, I tried this, but the rear side walls was really flat over the rocks and I was worried about losing a tyre. Cheers mate.

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Originally Posted by shayne86

I was just wondering what the more experienced disco owners do in regards to the large front and rear difference in recommended pressures. Not something I've had on any of my other fourbys

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I think you will find that most D2 owners don't run the plate pressures on the road.
I used to run my fronts at 36/38 and rears at 40/42 rather than the recommended (AFAIR) 28 / 40
Which might make ,the beach pressures being quoted, more sense,

Cheers Glen

28/40? Mine recommends 30 front and 38 rear.

In general off roading I usually go down to around 24psi. On the beach 18 psi.

Had a big dune at Beachport once that I could not get up.

Went down to 12 psi which got me up the dune, then back to 18 psi

As for the the rims, I am pretty sure the D1 and D2 are the same as far as the bead lock bit goes.

I have some of each lying around so will look tomorrow.