Tyre Pressures

Type in "4 psi rule"

1. Get pressure / load / speed charts in wrting from Bridgestone Tyres (not the dealer, not your 'mate', .......)
2. Follow them VERY carefully.
3. Be VERY careful of ANY other advise.

Cheers,
Peter
OKA196 Motorhome

Chris I find it depends a bit on what type of vehicle, the load being carried & how soft the sand is but in general most start at 18 to 20 psi dropping to 15 in hard going.
Cheers Craig...............

Hi Chris,

The advice above (except for Crackles) is OK for general running, but I think what you're after is pressures on sand...

It does depend on the condition of the sand and also your vehicle, but generally I would start around the low 20's. As Crackles says, if the going gets tougher, drop them down a bit more. I have had to go all the way down to around 12 for some dunes, but be careful not to corner too hard as you could pop the seal on a tyre.

The secret is to let it down sufficiently so the tyre bags out and lengthens the contact surface on the sand. Also need to be more aware of possible sidewall damage or staking as they will be more exposed.

Cheers
Gerry

Hi Chris,

The advice from others regards pressures for sand driving is pretty much spot-on, just be careful at really low pressures that you don't accellerate hard or corner hard as the lower pressure means reduced grip of the tyre on the rim.

You may be interested in the following...

I'm running Pirelli Scorpion LT AT's at the moment but have bought a set of Bridgestone 694 AT's for replacements soon - letting them age a bit. I sent an email to Bridgestone requesting recommendations regards tyre pressure for normal driving, highway driving and towing.

Alan Watts from Bridgestone rang me back and we had a chat about pressures etc. He has done a lot of testing regards the pressure increase from cold tyres to hot after driving, and reckons it is a lot of bunk!

The theory was that the tyre pressure will increase with temperature rise - ie driving - and if more than 4-5 psi then the tyre is getting too hot and is therefore underinflated. There is a basis of fact here (pressure WILL rise as the tyre gets hot) but how can an increase in pressure be a RELIABLE measure when there are so many other variables - mainly, cold day/cold road vs hot day and blistering hot bitumen.

Alan's recommendation was start at 35psi (for the 694's) and see how the tyres wear. If wearing in centre, pressure is too high.

I rotate my tyres at 5000k intervals and measure tyre wear. The Pirelli's were too high at 39psi, and I have dropped to 37 psi.

cheers,
glids

Having used the 694's on our last two vehicles and just completed a year of durability testing, Japanese vs Australian spec tyres, for Bridgestone I can offer the following guidance.

Test vehicle is a 120 Prado weighing in at 2400kg for daily use and when full loaded we run up to around 2950 kg. We average 20,000km off bitumen each year by the way.

Tyre pressures we use are:

Sand. Start at 16-18 psi

Off-bitumen/rocky terrain. 26 psi

Normal bitumen driving. 34 psi

One thing for all tyres is to ensur they are rotated and balanced every 10000kms to ensure even wear and tyre life

Regards

RobA

Ive been using 18psi in my 694 b/stones on the beach. I got a little stuck last week near the water so I went down to 10 psi and the landcruiser walked out .

So far I think they are great in the sand,maybe even better than the BFG a/t