Calculating tire-pressure for Old-timers
 

My name is Peter, and I live in Holland.
I dont have an old-timer but can give you information about calculating tire-pressure.
Once got hold of the system, the car-and tire- manufacturers use for calculating the advice pressures for cars.
The Equation for it is introduced in 1928 for diagonal tires, and has a power in it. At the introduction of radial tires they chanched the power in it diferent in Europe and America.
For Oldtimers you can use the simple Equation , because they dont drive faster then 99 miles/hour ,I asume.

I made spreadsheets for it , also in English.
The best one to use for Old-timers is the next, in wich you can fill in your own power.
So you can use for diagonal tires the old power of 0,585 and for radial tires 0,8 to calculate the maximum load for a sertain pressure. chanche the powers in the spreadsheet , there are 3 powers to fill in and you can chanche the steps to go down in pressure too.
http://cid-a526e0eee092e6dc.office.l...ulateload1.xls
Download and open the spreadsheet in Excell or likewise program to work with it, in the browser wont work because of protection for overwriting equations, I used in it.
Found this topic googling for tire-pressure, but cant find the topic anymore to react to.
If you cant work it out ask me here.
You need from the tire the maximum load and reference-pressure to be read from it in "maximum load xxxx lbs at yyypsi ( or kg and kPa)"
From the car the loads on the seperate wheels .
You can divide the loads you weigh by 0,85 to get the lowest load% , as I baptised it, at wich the ride is still comfortable and.
a Load% of over 100% gives tire-damage.
So always take enaugh reserve for pressure loss in time, extra incidental load, miss-readings of weight and pressure, and what I might forget to mention.