How to identify a slow puncture

Slow punctures are common, but they can also be very difficult to detect. This means that many of us could be driving around with a gradually deflating tyre for weeks or even months, without having any idea there’s a problem.

Let’s take a look at how slow punctures are caused, how to identify them and crucially, how to fix them.

What is a slow puncture?

A slow puncture is a tiny hole in a vehicle’s tyre, causing air to escape very gradually. It is unlike other larger punctures, which make themselves known almost immediately. If you suffer an ordinary puncture, you’ll notice the tyre deflating quite quickly. You may even be able to hear a gentle hissing sound coming from the tyre if you listen very carefully.

Both types of puncture can happen without the driver’s knowledge. You may only spot a change in tyre pressure when you get home, or the next time you try to drive the car. But with slow punctures, it can take days or even weeks for deflation of the tyre to become obvious.

Causes of slow punctures

Slow punctures are usually caused by driving over something sharp, such as a nail, screw or debris in the road. You can also get one by hitting a particularly nasty pothole or a kerb, which causes damage to the wheel rim or the sidewall within the tyre.

A less common cause of slow punctures is a fault with the tyre valve. If the cap doesn’t seal the valve tightly enough, or the valve dust cap is missing, the tyre can start to lose air. Dust and grit could even get into the valve with the same result.

Finally, slow punctures can sometimes be caused by damaged wheel rims, particularly on older cards with steel rims where there’s a gradual buildup of rust.

The warning signs to look out for while driving

While you may not notice a slow puncture at first, there are certain warning signs to watch out for when you’re on the road. For example:

• Drifting or pulling to one side. If you notice this happening while you’re driving, try this test. Find a quiet, straight and flat road and very briefly relax your grip on the steering wheel. If the car pulls to one side, it indicates a problem with the wheels or tyres. It could be an issue with wheel alignment, or it could be a slow puncture affecting tyre pressure in one of the tyres.
• Changes to vehicle handling. Does your suspension feel harder than usual or are there any other changes in the responsiveness of the car? If so, head to a repair centre to find out whether a slow puncture is the culprit.
• Continual loss of tyre pressure. A tyre with a puncture of any kind will gradually lose tyre pressure. If you’re always having to put air in your tyres, this could be a sign that something’s wrong.
• Vibration from the steering wheel. If you’ve started to feel shuddering or vibrations from the steering wheel, this could be caused by unbalanced tyres. It is particularly likely to happen when driving on the motorway or at high speed.
  

Identifying slow punctures on your driveway

As well as keeping a close eye out for warning signs of a puncture while driving, you should also do some basic checks before you get in the car. A visual check of your tyres could help you to spot an embedded object, as well as tyres looking a little more deflated than usual. You can also get yourself a tyre pressure gauge, a handy gadget that allows you to accurately check whether your tyres are actually losing pressure.

Why is it important to spot and fix slow punctures right away?

Slow punctures should always be looked at by an experienced, qualified technician as soon as they are detected. It may seem like a small issue, but if ignored it can turn into a major problem.

Neglected slow punctures can lead to larger leaks or tears, which can negatively impact safety and handling on the road. Your tyres are your vehicle’s only contact with the road, so they need to have good grip and performance. Crucially, they need to be in great condition so that you can maintain full control of the vehicle while driving.

If you ignore a slow puncture, the worst case scenario is a tyre blowout or even an accident. So, as soon as you spot it, get it sorted.

How to repair a slow puncture

In many cases, slow punctures can be repaired. It largely depends on what’s causing the problem. If there’s a nail or piece of embedded debris in the tread of the tyre, an experienced technician can simply fit a rubber plug to repair the hole.

However, such an easy fix may not be possible for high performance tyres. This is because these tyres are designed to withstand higher stresses than ordinary tyres, so they can’t have any vulnerabilities.

If your slow puncture has been caused by damage to the tyre sidewall, a dent to the rim or a corroded wheel, a repair may not be possible. In this case, a replacement tyre or other key component may be needed. Your repair centre will advise you on the best way to get your wheel and tyre back to full working order.

You may be tempted to repair slow punctures yourself, using a home DIY repair kit. This can do the job on a temporary basis until you can get professional assistance, but it isn’t recommended as a long-term fix for a slow puncture. The substances used in these kits won’t last, so you’ll eventually need to get the tyre fixed anyway.

If in doubt, always call in a professional. There could still be something embedded in the tyre, or a more serious issue (i.e. damage to the tyre sidewall) you aren’t able to detect. It’s not safe to drive on damaged tyres, and it’s just not worth taking the risk.