As a mechanic, one of the day to day tasks we carry out is check peoples tyre pressures. Whether it is during a service or if we’ve noticed it during a repair, it is always amazing how often peoples tyre pressures are low.
Why does this matter?
When a tyre is over or under inflated, it actually causes excessive wear to the tyres, often on the edges if under inflated or in the centre if over. This can be incredibly expensive for you because it means new tyre’s far more often.
The easy fix for this is to make sure that you check your tyre pressures fairly regularly, we would recommend at least every 2 weeks.
Tyre pressures are measured in a few different scales, though today we are only going to talk about psi (pounds per square inch). Though this is an older measurement, this is still the most commonly used on cars around Australia and the world and it is what you will find on most pumps.
When checking your tyre pressures, the easiest starting point is to find out what is recommended by the brand. This is commonly on a small sticker in one of the door jambs around the vehicle and is called a tyre placard (like the one below) which shows the size of tyre that should be fitted to your car and the manufacturers recommended pressure with psi in brackets.
Unusually though, we would normally recommend inflation a couple of psi (2-3psi) above recommended because brands tend to set their pressures for comfort instead of the best wear.
Generally, our mechanics would recommend 36psi for a small car, 38psi for medium sized cars (and small SUV’s), and 40psi for 4WD’s and if you don’t know exactly what is best for your car, don’t hesitate to ask a mechanic.