Tyre pressure: the cheapest maintenance almost nobody does

Tyre pressure is boring, which is why almost nobody checks it. Yet there is little maintenance that costs so little and returns so much.

What a soft tyre actually does

A tyre half a bar low deforms more with every rotation. That deformation becomes heat, and the heat has to come from somewhere. It costs you roughly 2 percent more fuel.

Worse is the wear. At low pressure the tyre carries mostly on its shoulders, so the outer edges wear faster than the middle. You only notice once it is too late and you replace a tyre earlier than needed.

Then there is braking distance. On a wet road the difference between a correctly inflated tyre and one not checked for six months can be several metres. That is exactly the part you need.

How often and when

Once a month is enough, plus before any long trip with a loaded car. Measure cold, so before driving or after a few hours parked. A warm tyre reads 0.2 to 0.3 bar high and then you underinflate.

The correct values are on a sticker in the driver's door pillar or inside the fuel flap. Note there are usually two columns: normally loaded and fully loaded. Going on holiday with a full boot means the second column.

What a compressor needs

• Automatic shut off. You set the target pressure and it stops by itself. Without it you are squinting at a needle with a phone torch.
• Enough pressure for your vehicle. Cars sit around 2.2 to 2.8 bar. Bicycles need more, road bike tyres go to 8 bar.
• Battery or plug. A rechargeable unit comes straight out of the boot without starting the engine. The downside is charging it, and a flat compressor at a flat tyre is useless.
• A light. Sounds unnecessary until you are on the roadside in the dark.

Our portable tyre inflator with LED light is rechargeable and shuts off automatically, so you can set it and put it down.

One thing that often goes wrong

The valve cap. It is not decoration, it keeps dirt and moisture out of the valve. A valve leaking through corrosion is the most common cause of a tyre that loses a little every month.