Tyre Pressure - Yes, another question!

[monty]

Hi all,
Had a look but couldn't find answer, so hopefully not repeating anything....
GQ 4,2 diesel long wheelbase, running BFG AT 265/70/16. Normal on road, just driver, vehicle stock standard, having replaced split-rims, so what pressure front and back? Also any suggestion when towing caravan on black top too (van ATM 1750, ball about 200kg)?
Thanks for your help,
cheers, monty

[92GQ]

Hi mate;

If it was me, I would probably have around 32-36 around town and 36-38 when loaded/towing.

[Drewboyaus]

I run 38 in my BFG KM2's when on the blacktop.

[NissanGQ4.2]

I run 40 in my BFG A/T's on the road

[threedogs]

No more than 40 psi loaded on the Hwy, and anything down to 16-18 off road depending on conditions

[BillsGU]

Go to a Coopers tyre dealer and ask for a brochure - or get one off their web site. They have lots of information on tyre pressure. Failing that - use the 4 PSI rule.

[Winnie]

Failing that - use the 4 PSI rule.

Seen people mention this before but never seen them explain what it is?

[Bloodyaussie]

Do we really have to have this discussion again........... I have spoken to many a tyre expert and they have laughed at much of the advice given here.

38-40 psi for normal use and under heavy load 42psi on the rear.

People who mention 32psi are so far off the mark its not funny.

What car manufacturers recommenced is to make you car appear more comfy but tyre makers suggest a much higher number.

Running low pressures on the road generates to much heat in the tyres.

When racing we ran low pressures during sprint races as we needed heat in the tyre quick as the race was over in 5 laps but during longer races if we ran the low pressures the tyre would go off and you would have to slow down to get the tyre back to safer temps.

[BillsGU]

Trouble is OZ - every tyre "expert" tells you something different (while laughing at what another "expert" told you). The 4 PSI rule works well off road and also on road. The idea is that you measure you tyre pressures and drive for a number of k's. You then stop and immediately measure the tyre pressure again. If it is more than 4 PSI above what you had before then there is too much flex in your tyres and you need to increase your pressure. If the temp increase is less than 4 PSI you are running your tyres too hard. This "rule" allows for all sorts of terrain, ambient/road temperature and varying vehicle loads.

[Bloodyaussie]

Trouble is OZ - every tyre "expert" tells you something different (while laughing at what another "expert" told you). The 4 PSI rule works well off road and also on road. The idea is that you measure you tyre pressures and drive for a number of k's. You then stop and immediately measure the tyre pressure again. If it is more than 4 PSI above what you had before then there is too much flex in your tyres and you need to increase your pressure. If the temp increase is less than 4 PSI you are running your tyres too hard. This "rule" allows for all sorts of terrain, ambient/road temperature and varying vehicle loads.

Trouble is not one tyre expert has said 32 psi in a heavy 4wd was a good thing........... we also use the 4psi rule when racing.. I have won state titles and many a club level championship and did not do so by saying "That will do" as far as set up goes.

If I went out running the wrong pressures that could be the championship over and made it my business to know every little thing including tyre pressures in wet/dry short/long and cold/hot races.

There have even been guys offering advice as low as 28psi for road driving, crazy.

Sometimes when fully loaded with a heavy gardening trailer I will run up to 48psi in the rear ... I tow a heavy trailer 300 days a year and tyre wear is important to me.

[monty]

Hi all, thanks for the suggestions. I'll try the 4psi rule and see where that goes, and thanks Bloodyaussie for the info on racing tyre set-up as I am getting a car ready at the moment for circuit sprints so that will help me there too.
cheers all, Monty