Why is my tyre losing air pressure?

Why your tyre keeps losing pressure

A tyre that repeatedly loses pressure needs attention. There are several common causes, some more serious than others.

Common causes

• Slow puncture — A nail, screw or sharp object embedded in the tread. This is the most common cause.
• Damaged valve stem — A cracked, corroded or loose valve allows air to escape slowly
• Poor bead seal — The seal between the tyre and the wheel rim may be compromised, especially on alloy wheels where corrosion can build up
• Sidewall damage — A crack or impact mark on the sidewall can cause slow leaks
• Temperature drops — Cold weather naturally reduces pressure. If the tyre only seems low in cold mornings but holds pressure otherwise, this may be the cause.

What to do

If your tyre keeps losing pressure after being inflated, do not ignore it. Take the car to a garage for inspection. A slow puncture can usually be found quickly by submerging the inflated tyre in water or using a soapy water spray to identify the leak.