Tyre Repair: Puncture Repairs

A tyre puncture, better known as a flat tyre, is a condition in which a pneumatic radial deflates causing the wheel's rim to ride on the ground or on the tread of the tyre. This could potentially lead to loss of vehicle control or permanent tyre damage.

How Dangerous is it?

In case of a flat tyre, you must gradually slow down and come to a standstill on one side of the road. If you continue to drive, you might end up damaging the wheel or be responsible for a deadly accident, in case the speed is high and you lose control.

What causes tyre puncture?

More often than not, a puncture is caused by a foreign object penetrating the tyre (for example, a nail). Similarly, impacts such as driving over a pothole or hitting a kerb can cause a tyre to go flat.  Slow punctures are a safety hazard as they can lead to blow outs at high speeds. However, early detection can reduce this risk. Be sure to check the condition of your tyres regularly.

What sort of punctures can be repaired?

Tyre repairs are only permitted in the treaded area of a tyre - the area that makes contact with the road surface. These are deemed as 'minor repair zones'. Repairs are not permitted in 'major repair zones', i.e. the sidewall, or any other areas of the tyre.

Common Causes of Tyre Punctures

The most common cause of a tyre puncture could be slow or rapid deflation of a tyre, depending on its size, due to a sharp object penetrating it on the go.

Other factors that could cause a tyre puncture are:

  1. Failure of a tyre's valve stern.
  2. Breakage of the link between a tyre and rim owing to a collision with an external object.
  3. Excessively worn out tread that could result in an explosive tyre failure or debris from the road tearing through the tyre.

When (and When Not) to Repair a Tyre?

Tyre Puncture Repair is a tedious task and not as straightforward a process as it may seem. These are regulated by a certain BSAUl59 British Standard that defines limits to the repair materials that can be used and total number of repairs that can be carried out on a tyre, based on the tyre size and location of the puncture.

A tyre must be thoroughly inspected before repair and a repair must not be attempted in case of any of the following symptoms:

  1. Tread depth below the legal limit of 1.6mm across the tyre's circumference.
  2. Broken structural integrity or run flat damage.
  3. In case of any damage caused by an external object.
  4. Worn out, aged or deteriorated rubber.
  5. Exposed cords.
  6. Any sign of previous faulty repairs.

In case you are uncertain about whether your car tyre must be repaired or not, seeking expert advice is a must.

Tyre Repair Services Available at National Tyres and Autocare

Skilled, experienced and certified tyre technicians carry out the following tyre repair and maintenance services at National Tyres and Autocare:

  1. Puncture repairs
  2. Wheel balancing
  3. Wheel alignment
  4. Damage repairs due to tread penetration by sharp objects like nails, glass or metal
  5. Tyre pressure checks

Book a "tyre health check-up" today or drive into your nearest branch. Your life is precious. And it depends on your tyre's health.

Puncture repairs are carried out in accordance with NTDA and BSAUl59 regulations which stipulate that:

  • Tyres can only be repaired in the area marked 'T'.
  • For tyres rated 'V' and above, only one repair is allowed.

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In every case the tyre should be inspected and if any of the following are noted then it shouldn't be repaired:

  • Illegal tread depth (below 1.6mm across the central ¾ of the tyre tread throughout the entyre circumference)
  • Run flat damage - breakdown of the tyre's structural integrity
  • Secondary damage - caused by the injuring object
  • Ageing/deterioration of tyre rubber
  • Bead damage
  • Exposed cords
  • Faulty/poor previous repairs
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Pre-puncture sealants

These are injected through the valve as a preventative measure. The aim is to prevent air loss if a puncture does occur so that you can drive on without interruption. If the sealant works, then the seal will be pretty much instantaneous after puncture. However, this does raise concerns that you'll have no idea whether there's been a puncture or not. A large screw or nail in the tread will cause further damage over time and could lead to more catastrophic failure. Experts recommend that you should check your tyres every time you use the vehicle if they contain a pre-puncture sealant. If the sealant has been activated you should see signs of the sealant (usually white latex-based) on the outside of the tyre. If there are any signs of this or of a penetrating object, then the tyre will have to be taken off the wheel rim and checked to see if it is suitable for a permanent repair.

Post-puncture sealants

These are used following a puncture. You inject the sealant through the valve and then use the compressor or cylinder of compressed gas to re-inflate. A can of sealant can bring peace of mind, but it’s important that you spot the puncture early and stop quickly. Driving on a tyre in a partially or fully deflated condition will cause weakening of the structure and irreparable damage. Because a tyre has to be removed from the wheel and checked for internal damage before it can be repaired permanently, sealants cannot be considered permanent repairs.

Run flat technology

Although, in theory, it’s possible to fix a puncture on a run flat tyre, we have taken the decision not to extend our puncture repair service to this particular tyre technology. The reason is simple: it is impossible to assess exactly how much damage has been caused to the tyre and wheel, and not carrying out a repair is the only way we can guarantee driver safety.

Run flat technology means that the tyre can resist the effects of deflation after sustaining a puncture, giving the driver enough time and mileage to get back home or to the garage. It's even more helpful given that not all modern vehicles contain a spare tyre as standard. All run flat tyres come with recommended guidelines on how many miles or at what speed you can drive on them after sustaining a puncture, and if you exceed these guidelines then you will cause integral damage to the tyre. Unfortunately, as there is no way of us determining how far or how fast a vehicle has been driven since the puncture occurred, it would be impossible for us to know whether the strength and composition of your tyre has been damaged. Making a repair to a damaged tyre is a surefire way of diminishing tyre safety, which is something that we wouldn’t advise or want to profit from. Your safety is our main priority, so we pride ourselves on delivering a cost-effective and proficient service.  

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