Max psi on tyre

[wbowner]

Hi
I have been keeping an eye on the tyre pressures for my new hankook tyres
255/55r19
The max psi on the tyre is 50 psi , I assume as measured cold

I have a tpms so have been looking at the bloody things all the time

I am towing a van around 2000kg

I have tried to keep to the 4/6 psi rule by varying the pressures.
The front tyres I have set to 40 psi and they have gone to 43/44 according to the tpms, I may drop to 38 and see

I initially set the backs to 44 psi and they were raising to 49 psi so I increased the pressure to 45 and the tpms alerted me I had exceeded the 50 psi high value, it was 51/52 psi - hot

My question - is it a problem if the psi - hot exceeds the tyre max psi, if not much before I panic.

I will drop the back tyres to 44 cold again and see


Richard

[Owen]

Richard, the cold at 50 psi is correct for max, don't be surprised if they get up a lot more under tough conditions. I used to run 50 psi in my all terrains on my old patrol, towing a heavy trailer in the NW of WA. With hot conditions, the road would stick to your boots....and towing would get the tires very hot and pressure would go from 50 in the morning cold to 65 once the heat got to it. Never a puncture or blow out though, those tyres still on the old beast !

Check the ball weight, the air suspension gives a false sense of security and the extra weight might be contributing, otherwise don't stress about hot tyres getting over 50 psi.

I like to use the front/rear "footprint" as my guide, same tread length on the road and often it takes about 5 to 8 psi more on the rear to get a match when loaded.

use the tpms more for picking up a slow leak, a great safety system.

[wbowner]

Richard, the cold at 50 psi is correct for max, don't be surprised if they get up a lot more under tough conditions. I used to run 50 psi in my all terrains on my old patrol, towing a heavy trailer in the NW of WA. With hot conditions, the road would stick to your boots....and towing would get the tires very hot and pressure would go from 50 in the morning cold to 65 once the heat got to it. Never a puncture or blow out though, those tyres still on the old beast !

Check the ball weight, the air suspension gives a false sense of security and the extra weight might be contributing, otherwise don't stress about hot tyres getting over 50 psi.

I like to use the front/rear "footprint" as my guide, same tread length on the road and often it takes about 5 to 8 psi more on the rear to get a match when loaded.

use the tpms more for picking up a slow leak, a great safety system.

Owen
Thanks for the quick reply

Using the tpms as I have been drives you crazy I reckon.

The trouble is it varies a bit. Sometimes spot on with my gauge somtimes higher and sometimes lower but always close

I did get it for the leak situation so should stick to that
I have two good gauges
A jamec-pem dial one and a michilen vigil which vary a bit as well but are more consistent
I normally use the jamec-pen one but the Michelin one is easier to use. The Michelin one is normally 1 psi lower.

I think I will make my pressure decisions based on the gauges

The idea of the foot print is good but how do you do that accurately?

Thanks again
Richard

[jon3950]

The idea of the foot print is good but how do you do that accurately?


Count the number of tread blocks along the shoulder of the tyre that are in contact with the ground. Doesn't need to be super accurate.

This technique is especially useful when lowering pressures off-road to get similar grip levels front to rear.

Cheers,
Jon

[wbowner]

Count the number of tread blocks along the shoulder of the tyre that are in contact with the ground. Doesn't need to be super accurate.

This technique is especially useful when lowering pressures off-road to get similar grip levels front to rear.

Cheers,
Jon

Jon
Thanks for that I will give it a go

Richard