eli5: Why can you only learn your proper tire pressure from the car and not from the tires themselves. Wouldn’t different kinds of tires need different pressures on the same car?

Question

Same tires, different cars = different recommended tire pressure

Different tires, same car = same recommended tire pressure

This doesn’t make sense to me. Why is this?

In: Engineering

Answer 1

Imagine chopping your tire in half, the grippy bit should be as flat on the road as possible not enough air and it will go flatter, also a heavier car will make it go flatter.

Put too much air in and it will start to go round on the bottom, lifting the edges a bit.