Tyre Operating Temps

The 4 psi rule has always worked for me.
Inflate to recommended pressure or whatever you fell is right.
Drive for a half an hour or so then check the pressure, if it has increased by 4lbs then you are about right for the speed and load you are travelling at.
If the pressure has increased by more than 4lbs then you did not have enough in originally for the speed and load.
If the pressure has increased by less than 4lbs then you originally had too much pressure originally for the speed and load.
Tyres should always be checked cold initially.

Hi Time

I don't have one of those units so I can't give precise advice but I'll just kick in a little theory until someone comes up with something better.

The air temperature inside a tyre rises approx 6c per psi increase over ambient.

Normally tyres are adjusted to give up to 6 psi above ambient and a 10 psi rise would be coause for concern.

So on a 45c day a 10 psi increase would cause an internal temperature rise of roughly 60c

From the above I would set your monitor at about 95c

There is no such thing as a "normal" operating range of tyre temperatures that you can rely on. Simply does not exist.

If you now monitor your TPMS and set it within the normal tolerance range, normally up to around 84C, then you will see that your tyre temperatures, regardless of pressure, will actually vary front to rear and also loaded vs unloaded.

Just make a note of what condition the vehicle is in against the temperatures and you will then establish your "normal" range.

We have seen up to 10C variations front to rear and as high as 62C on baked bitumen with the roof rack on and air temperature of over 40C.

The TPMS give you advanced warning of a slow leak as the pressure can be almost normal but as the tyre slowly leaks it creates more rolling resistance (heat).

We have tested several systems and are currently using the Schrader one which is now optional equipment on LC200.

I hope that helps

Regards

RobA

Time

Nothing silly about the question.
I run a tyre monitoring system. It has an inbuilt table it uses to determine a temp problem.
As an example of the influences on tyre temp.
Last year while traveling west in the desert.
Mid morning tyre pressures 17-18 psi.
Tyres on the right hand side hot to touch.
Tyres on the left hand side cool to touch.
Average speed slow.

Regards

Thanks for your quick replies. Very useful.

I am also running the same brand tyre but in a 265x75x16 size run these because we did 80psi cold for the GMC also found that the 4 psi rule which i have always used seems to be out on theses tyres could it be because there are 10ply tyres but even at 80psi can be up to p2psi after a run which would suggest that the tyres are underinflated but 80psi is the max cold pressure stated on the tyre.