Yvan wrote:
Not a surprise it doesn't work. It's a bogus formula. It assumes the
tires have no effect at all on the load-carrying capacity and the tire
footprint. They have a very large effect on both.

The tire pressures listed in your manual are those which will allow for
uniform wear on the tires at a certain load, plus keep them safe. These
have been skewed in recent years since increasing the tire pressure
increases the MPG of the vehicle by reducing rolling friction. Since
manufacturers like to advertise as high an MPG (and avoid gas-guzzler
taxes in the USA) - they tend to set the tire pressure higher than
optimal for ride/handling/comfort/wear.

It's a whole bunch more complex than simply dividing PSI by weight..
although I guess that sounds like a nice idea.

admin wrote:

Well, actually it worked quite well after we found out the true weight of
his car vs the weight the placard was written for. His car was modified.

You should read the rest of the thread.

Frank