How long can you drive with a slow puncture?

By Julia Freeman

This question could be re-phrased as “how long will it take to wreck my car?”. Correct pressure in your car tyres is essential for your safety, and also protects the tyres, transmission, and fuel economy. Of course, the faster the leak, the bigger the worry.

Quick tyre checks and advice are free at every Protyre garage, so the most sensible way to answer this question is to let our tyre professionals inspect it. Why take a risk?

How slow is slow?

All tyres slowly lose air – in fact, 2psi per month is normal. If one tyre loses more, you have two things to worry about; can you maintain a safe pressure in it and why is it leaking?
 
Accelerated leaking can be caused by potholes, riding the kerb, direct sunshine, rim corrosion, faulty valves, or a hole, but if you cannot rule out structural tyre damage then you should never delay a proper tyre investigation. Structural damage can lead to a blow-out at speed. Always decrease your speed and drive carefully on a tyre you know to be leaking.
 
If you can maintain a safe pressure by pumping up more often, you can carry on driving until you can get it fixed. Don’t be tempted to put extra pressure in because, generally speaking, over-inflation is more dangerous than under-inflation. In particular, it degrades grip and braking. Even on an undamaged tyre, an excess of 3psi is too much. You can risk a little more under-inflation but not much. Contrary to what many people assume, under-inflation makes a blowout more likely, because increased road friction heats the tyre and flexes the weakened rubber.
 
If you have TPMS in your car, you will get a warning from your dashboard when your tyre pressure is leaving the safe range. If you don’t, it is best to have your own pressure gauge. Car tyres should be checked cold. When you call into a service station they hardly ever are.

Tyre repair

DIY roadside repair kits sometimes work – if you can find the leak – but they are only intended to help you complete a journey or find a garage. Our tyre professionals can safely restore most car tyres to their normal lifespan. We do not recommend tyre sealants; they don’t provide a safe seal (if any at all), can rot the tyre, and gum up the valve.
 
In a professional repair, the tyre is removed and inspected internally. If structural damage is discovered the tyre cannot legally be repaired, nor can it be refitted. In almost all cases the structural damage has been caused by driving too fast or too far on wrongly inflated tyres.
 
Most run flats can’t be repaired. Pirelli just say no. They tell garages not to repair them because it is too difficult to tell if the motorist kept within the 50 miles under 50mph rule. Continental says the same. Bridgestone is more inclined to take the motorists word for it, and Hankook say it is okay if you kept it above 15psi. However, it is worth noting that repairing a run flat could invalidate your car insurance.

Book with Protyre

This is another good reason for going to a Protyre garage near you. Our wide tyre range of Pirelli, Bridgestone, Michelin and budget tyres will make it easy to find a match for your car and your pocket. With our easy-to-use tyre guide, you can find the right tyres for your car in a few simple clicks – you can either search by your vehicle’s registration, or by tyre size, using the information embossed on the side wall of your existing tyres for help.

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About the author

Article Author Photo
By Julia Freeman
Julia is Head of Retail Marketing for Protyre and loves engaging with customers and the business as a whole to make sure Protyre is more than just a local garage.
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