Punctures get the attention. Pressure does the damage.
We see the inside of a lot of tyres in Silverton, and the casings that arrive tired are rarely tired from nails. They are tired from months of running soft, flexing in ways they were not built to flex, building heat on every trip until the structure gives up quietly. The two-minute check that prevents it is the one most people skip because they are not sure what the right number is.
So here is the whole thing, including where the right number actually lives.
What is the correct pressure for a tyre?
There is no correct pressure for a tyre on its own. There is a correct pressure for your tyre on your vehicle, and the vehicle manufacturer sets it. Find it on the placard in the driver's door jamb, sometimes inside the fuel flap, and always in the owner's manual. That is the figure to set, cold.
The placard usually lists more than one set. There will be a normal running figure, often different front and rear, and frequently a second, higher set for a fully loaded vehicle. Some placards add a towing set. All of them were arrived at by the people who built the car and know how its weight sits.
Does tyre size determine the correct pressure?
No, and this is one of the most common wrong turns people take. Two different cars fitted with identical tyre sizes can have different recommended pressures, because pressure follows the weight of the vehicle and how that weight distributes across the axles. Search your car, not your tyre size.
While you are at the sidewall, though, there is a number moulded into it that deserves a warning. The pressure printed on a tyre is that tyre's maximum, not a recommendation for anything. Set your car to it and you will usually be over-inflated, riding hard, with the centre band of the tread wearing ahead of the shoulders. It is a genuinely easy mistake because the number is right there in front of you when the placard is not. The rest of the markings are decoded in how to read your tyre sidewall.
Should you check tyre pressure hot or cold?
Cold, which means before you drive or after the car has stood for a few hours. Air expands as a tyre warms, so a reading taken at the end of a run reads higher than the truth. Worse is what follows: letting air out of a hot tyre to hit the placard number leaves you under-inflated once everything cools.
If the only gauge you have is at a filling station at the end of a drive, take the reading, note that it is high by a margin you cannot measure, and check again properly in the morning. Do not bleed air to reach a cold-pressure figure with hot tyres.
How often should you check tyre pressure?
Once a month, and before any long trip. Tyres lose air slowly on their own even when nothing is wrong with them, and a month is long enough for that drift to matter without being so frequent that nobody keeps it up.
Add a check whenever the load changes meaningfully. A bakkie carrying a full bin, a boot packed for the coast, or a car with a trailer behind it is a different vehicle from the one the normal figures were set for, and the placard's loaded numbers exist for that trip.
What under- and over-inflation look like
A worn tyre tells you which mistake was being made, and you can read it with your eyes and a hand.
| What the tread shows | Usual cause |
|---|---|
| Both shoulders worn, centre band standing higher | Running under-inflated |
| Centre band worn, shoulders still healthy | Running over-inflated |
| One edge only, or a feathered edge you can feel | Alignment, not pressure |
Under-inflation is the expensive one. The sidewalls flex further than they were designed to on every rotation, that flexing makes heat, and heat is what breaks tyres structurally on a long run. It also costs fuel on every kilometre. Over-inflation is less dangerous but wears the middle of the tread and makes the car ride harshly over everything.
If the wear is on one edge only, stop looking at pressures. That pattern points at the angles the wheels sit at, which we covered in wheel alignment vs wheel balancing.
A warning light is a late signal
Many newer vehicles monitor pressures and will put a light on the dash. Treat that light as a warning that something has already gone significantly wrong, not as a substitute for a gauge. Systems typically alert once pressure has dropped well below where it should be, and by then the tyre has been running soft for a while.
A gauge costs very little and lives in the cubbyhole. Use the light as a backstop.
What our treatment does and does not change
Our Nano Polymer coating goes on the inside of the tread and cures there. In the tread, it seals as it happens, and in most cases you can keep rolling to somewhere safe. That is what it does, and you can watch how it is applied on our how it works page.
Here is the honest half. The coating does nothing about pressure. It does not slow the ordinary loss of air, it does not fix a leaking valve or a bead that is not sealing properly against the rim, and it does nothing for sidewalls, impact damage or anything already wrong with a casing. A treated tyre run at the wrong pressure wears out exactly like an untreated one. The monthly check stays yours.
That matters on a long trip in particular, where soft tyres and highway heat work together. What to do if one does go down on the road is in our practical guide to Gauteng highways.
Check them this weekend
Take a torch and a gauge to the driver's door jamb, find your two sets of numbers, and set all five tyres cold, spare included. It takes about two minutes for the whole car.
If the sidewalls tell you a story you do not like when you get down there, photograph the tread and sidewall and send it to +27 76 089 4066. We will tell you what we see. If you want the treated set before the next long run, the booking page is open.