Opinion on Tire Pressure / Clueless mechanics?

[fireheart]

Sorry. I have a 97 Toyota RAV4; a lightweight not-quite-SUV called a 'crossover utility vehicle.' It seems stock tires call for something in the neighborhood of 30psi, which seems awful low to me, but then again, my car is hardly ever heavily weighted down. I just can't believe this has never been told to me before.

Stock standard in Australia for cars is between 32-36psi depending on the car. The Big Black Van (aka Volkswagen Transporter) and the FAmily Car (Suzuki Vitara) both get a bit more as they're huge. Dad always gets me and my sister to do 32 for safety's sake, although the max for both of ours is 34.

[Frantic Freddie]

I'm going to buck the trend here a little bit.

I'm also going to guess that you drive a pickup or full-size van/ SUV.

If the tires are passenger type tires, on a less than 4000lb (1900kg or so) car then you probably should not be running them at 51psi.

These sound more like light-truck (usually marked "LT") tires, which are made to handle higher loads than passenger tires, and typically should be inflated to 50psi.

As a lark, you may want to look at the tire pressure rating on the next semi you see in a parking lot - those often run 100 to 125psi.

I run LT 245.75/16 (Pro-comp All-Terrains) on my Grand Cherokee,max inflation is80 psi but I NEVER run them that high,I go by the doorjamb sticker,32-35 psi (yes they make the ride stiffer but I don't get flats on my dirt road with all the rocks & I do take it off-road)

100k niles on a set of tires?!? I've never seen a tire rated for that distance,most are 40-50k & by then they're bald. Not callin' you a liar LillFilly,but are you sure it's 100K?

[Seshat]

That's the other thing the tread gauge is useful for. Once the tread gets below one mark, it's time to save for new tires. Once it gets below the second mark, you either buy new tires or stop driving the damned car.

[Andara Bledin]

Another thing that I don't recall being mentioned. Tire pressure increases while the car is being driven; the tires heat up while in motion.

I think the pressure is supposed to be checked before they get hot, but I'm not certain.

^-.-^

[It's me]

Another thing that I don't recall being mentioned. Tire pressure increases while the car is being driven; the tires heat up while in motion.

I think the pressure is supposed to be checked before they get hot, but I'm not certain.

^-.-^

Correct. Tire pressure should be measured with tires cold.

[Greenday]

From what I know, most tires should be somewhere between 30-35 psi. Putting them at max while cold is a terrible idea since it'll increase with heat.

Unless your car's manual says otherwise...