tire psi question

[YY1]

I'm on year 9 on my Cooper Cobras. I'll replace them in 27. I think I rotated the tires 1 time.

About 1000 miles per year, so only about 9-11,000 miles on the tires

You're lucky.

The first set of fronts I had of Cooper Cobras only lasted 4 years driving nearly every Friday and sometimes all weekend.

Tread was fine...busted belt....again.

The rears, however...are still on the car almost 14 years later.

Where's some wood to knock on?

 

[dr dodge]

Chalk works well. If you do chalk test, try it with the tire hot at driving temps. Tire pressures increase with heat.

Note cold temp pressure, get them up to temp. Chalk and observe. Same approach as described. Inner wear, air out, outer add air. Take hot pressure reading, make adjustments. Add subtract adjustments to the cold pressure and you'll likely be close enough.

on the dirt cars we player with a yellow wax/grease pencil
we drew up the sidewall and watched for the scrub line,
where the sidewall / tread /roll under "transition" was.
a low tire moves it down, high moves it up
and you can actually drive the car in normal conditions,
you read the feathering of virgin line to none
and lots of lines also works to find a bum tire
scrub like not centered in the wheel center