8 stud tubeless rims to suit 1973 Denning

I put Ford F350 8 stud alloys on my OKA. The Ford tapers were different to the OKA wheel tapers. The local engineering shop retapered them to fit OKA nuts while I waited for $15 per wheel. (So as I could still use the original OKA heavy steel wheels as spares)

Hi Cobba
When the tyres were fitted the put 100psi in them. After driving for a while they reached 130psi.
I lowered them to 90psi the next day and they reached 120psi.
I now start off at about 85psi and they still get to 110psi+
Wheel alignment was done a short time ago.
Cheers
Ash

Thanks Paul
As soon as I can source the right rims I'm going tubeless for sure.
Regards
Ash

Hi jon_d
I'll let yo know.
Cheers
Ash

Are you checking the pressures with the same gauge, is it a good quality tool?
Those increases are abnormally high. I'd be checking that the brakes aren't dragging and the bearings are properly lubricated.

When the tyres were fitted the put 100psi in them.

There is a standard formula to determine air pressure in a tyre. It requires you knowing the weight on each axle.


Find the maximum cold tyre pressure (written on the tyre) and divide it by the maximum load of the tyre (also usually written on the tyre - noting whether is a single tyre or dual tyre).

Then multiply it by the weight of the axle and divide by the number of wheels on the axle.


Maximum cold tyre pressure (written on the tyre) / the maximum load of the tyre * the weight of the axle / number of wheels on the axle. = suggested air pressure.

When I was at the sandblasters ,the labourers there would regularly fill their tyres from the air system......then they'd say how the car was driving funny.......with 125psi in the tyres.............some of them had bicycles ,and would regularly have bike tyres explode .....and wheel barrow tyres ......who da thunk a Chinese wheelbarrow tyre wouldnt take 125psi...........between shifts ,the air would creep up to 150psi ,and all the safety valves dribble.

I also recall being told "never bleed air from a hot tire"

It does sound as if as suggested a dodgy gauge or a mechanical issue causing those variances.

Here are the 4 laws controlling the situation (to get the pressure/volume/temperature relationship.

This first one is a good starter and refers to the others.

Boyles Law


Charles Law


Gay-Lussac's Law


Avigadros Law deals with hypothetical "Ideal Gas" and should not worry our brains.