Tyre pressure is measured in PSI (pounds per square inch) or BAR. Every vehicle has a recommended pressure rating, usually found on a sticker inside the driver's door frame or in the owner's manual. This figure differs between front and rear axles and changes depending on load — for example, carrying a full car of passengers requires higher pressure than driving solo.
Under-inflated tyres are one of the most common causes of tyre failure on UK roads. Running at low pressure causes the tyre sidewalls to flex excessively, generating heat that can lead to a sudden blowout. It also increases rolling resistance, meaning your engine works harder and uses more fuel. Over-inflated tyres, on the other hand, reduce the contact patch with the road, making handling unpredictable and causing the centre of the tread to wear out faster.
Check your tyre pressure at least once a month and always before a long journey. Pressure should be checked when the tyres are cold, as heat from driving increases the reading. If you notice one tyre repeatedly losing pressure, this could indicate a slow puncture — a common issue on Cardiff roads where pot holes and debris are frequent. Royal Mobile Tyres offers same-day puncture diagnosis and repair across the Cardiff area.
