How do you find base tire pressure?

[65coupei6]

Probably no one here runs stock tires. So how do you find a base tire pressure to
play with?

This is what I figure. Let me know if there is a better way of doing it.

My other car (little Mercedes sports car) has tires that read 40 max PSI
The door jamb reads 28 Front / 32 Rear.
Rear is about 20% less than max PSI
Front is about 30% less than max PSI

So, the Mustang tires read 44 max PSI
Rear I figure to run about 35 PSI
Front I figure to run about 30 PSI

Any other suggestions??

 

[Midlife]

Here's the best way I've found to find the correct tire pressure.

Wet a spot on dry pavement where the tires can run over. Take the car and drive the tires over the wet spot and immediately examine the wet marks left by the tire on the dry pavement, particularly when the marks finally disappear. When the marks disappear evenly across the entire face of the tire tread, you've got the right tire pressure to give you maximum traction.

There will be a range of about 6 psi. Adjust your pressure within that range to your liking: lower for more comfort; higher for better mileage.

 

[Anonymous]

You can also go out and flog the #$!* out of the car and and take tire temps with a probe. Should be even all the way across the tire.


Preferably in a track setting!

 

[Sluggo]

Or drive it across a dusty floor like in a body shop and look at the tracks.

 

[cmayna]

Here's the best way I've found to find the correct tire pressure.

Wet a spot on dry pavement where the tires can run over. Take the car and drive the tires over the wet spot and immediately examine the wet marks left by the tire on the dry pavement, particularly when the marks finally disappear. When the marks disappear evenly across the entire face of the tire tread, you've got the right tire pressure to give you maximum traction.

There will be a range of about 6 psi. Adjust your pressure within that range to your liking: lower for more comfort; higher for better mileage.

Very interesting. What does the disappearing line look like when over and under rinflated?

 

[Sluggo]

The under inflated area would leave more water behind which would dry slower than the more inflated areas.

 

[AzPete]

The other thing, you can look at the tread pattern left from the wet tire and compare to the tire. You want the most tread with equal pattern size across the tire using the full tread width.

 

[Midlife]

The under inflated area would leave more water behind which would dry slower than the more inflated areas.

I understand what you're saying, but it leaves room for ambiguity.

Examine the wet marks left by the tire beyond the wet spot. With underinflated areas of the tire, the tire will retain water a longer distance; the over-inflated tire will lose water quicker or closer to the wet spot. You want consistent and equal water retention across the width of the tire patch as a function of distance from the wet spot laid down on the concrete to provide the source of water.

 

[cmayna]

Well Midlife since you obviously are so knowlegeable about examining :shee wet spots on the concrete floors of a barn, how could any of us challenge your words of wisdom?

 

[Midlife]

Easily...I'm wet behind the ears!