How low can I go?

[chops110]

G'day all, after some sage advice about reducing trye pressures.

My defender runs standard issue General Grabber 235/85R16's. These are high-profile light truck style tyre that run at 35-48psi on the road.

The magazines all talk about 18-20psi as a good pressure for general 4wd-ing with some sand, but I'm not sure I'm brave enough to take a high profile light truck tyre below 20...:(

Any advice?

Cheers

chops110

[TimNZ]

I regularly run my General Grabbers down to 14psi for the soft sand over here in WA, (18-20psi in the rockier parts). I have run as low as 10psi to get out of trouble, you just have to be careful not to be too aggressive when cornering.

Obviously the lower the pressure, the lower you must keep your speed!!

[ADMIRAL]

I have two friends with Defenders. They struggle in sand at the pressures we use (16- 18 PSI ) They go down another 2 - 3 psi and they manage fine. Amazing what difference a few PSI actually makes.

[yt110]

I have two friends with Defenders. They struggle in sand at the pressures we use (16- 18 PSI ) They go down another 2 - 3 psi and they manage fine. Amazing what difference a few PSI actually makes.

Do they run these low pressures loaded with all their camping gear or empty?

[chops110]

Sounds like I can go a bit lower then...I don't often run with much of a load on board so I'm not too worried about weight, just rolling the trye off the rim on a corner.

Thanks for the advice!:)

Chops110

[Blknight.aus]

in an emergancy, with suitable care for steering and right boot inputs you can go as low as 4psi.

Remember to apply the golden rule... As tyre pressure comes down so does speed and agression.

I usually recommend 15psi as the usual minimum pressure you want to go down to.

[ADMIRAL]

Do they run these low pressures loaded with all their camping gear or empty?

In sand yes loaded to the gills, and even towing a camper trailer. Note the camper trailer also has the pressures dropped, but only to 16- 18, as it runs 285/75 x16's.

A case of being sensible once the pressures have been dropped. Once you are down around 10 -12 psi, aggressive driving is asking for trouble. Even go down to 6 psi to debog, but ' gently bentley' is the name of the game, and air up a bit as soon as conditions allow.

I have always worked on the thirds rule. 1/3 off bitumen for rough gravel, another 1/3 off for sand. If using say around 40 for bitumen, try 28 for gravel, and 16 for sand. It's only a general average. Works for me.

[chops110]

Thanks for the tips

I think I'll set the Stauns a bit lower then :D

Cheers

Chops110

[billiardbrett1]

The first thing you have to remember is that air pressure at sea level is 16psi, any lower than that and you run the risk of the tyre rolling off the rim.however as most have said you can go much lower with careful driving. Just be careful if you are cornering as it isn't much fun trying to reseal a tyre on the sand

[clean32]

The first thing you have to remember is that air pressure at sea level is 16psi, any lower than that and you run the risk of the tyre rolling off the rim.however as most have said you can go much lower with careful driving. Just be careful if you are cornering as it isn't much fun trying to reseal a tyre on the sand

EH ???

[JDNSW]

Ignoring the difference between "gauge" pressure and absolute pressure.

Atmospheric pressure at sea level is 14.7psi, but almost all gauges, including the ones you use to measure tyre pressure, read zero at atmospheric pressure. So the pressure in the gauge is the excess pressure above atmospheric - what atmospheric pressure actually is, is irrelevant.

By the way, I agree with Dave's pressures. I would add that you have to be more careful, and set a higher minimum, for low profile tyres, as the tread is likely to hit the rim at higher pressures, other things being equal. As with most offroad situations, the higher the sidewalls the better.

John

[DEFENDERZOOK]

ive got a defender running the factory grabbers......
on stockton beach i run them at 12 psi without any problems.....and thats with a fair bit weight on board.......

my defender doesnt really like the soft sand with any more air than than about 15 psi......
dropping to 12 psi makes it alot easier.....which reduces strain on the engine and other components.......