Tyre & Alignment Professionals

01376 511177 Unit 6, Moss Road, Witham, Essex CM8 3UQ

01376 511177

The family run tyre team
with over 100 years experience
between them

Puncture Repairs

If you get a puncture you might be able to get it repaired for a fraction of the cost of a new tyre if the puncture is in the main tread area and you stopped quickly without overheating the deflated tyre. British standard BS AU159 sets out the rules for repairs to car tyres. It defines the type of damage that can be repaired and the way that repairs should be carried out.

One of the most important requirements is that the car tyre has to be removed from the wheel to check for internal damage. If not spotted this could later result in sudden failure of the tyre. Because of this, externally applied plugs and liquid sealants injected through the tyre valve can not be thought of as permanent repairs.

Tyre sealants

Many car manufacturers now supply a tyre sealant and tyre-inflator pack instead of a spare wheel. The sealant and compressed air are injected through the tyre valve but the result achieved will depend on the cause of the puncture and how far and fast the flat tyre has been driven on

There are two basic types of sealant, those that are put into the tyre in case of a puncture and those that are put in following a puncture.

Pre-puncture sealants

These are injected through the tyre valve as a preventative measure. The aim is to prevent air loss if a puncture does occur so you can drive on without interruption.

If the sealant works then the seal will be pretty much instantaneous after the tyre has been punctured. This raises the concern that you will have no idea whether there's been a puncture or not. A large screw or nail in the tread of the tyre will cause further damage over time and could lead to more catastrophic failure.

Post-puncture sealants

These are used following a puncture. You inject the sealant through the tyre valve and then use the compressor or cylinder of compressed gas to re-inflate the tyre.

If you regularly drive alone then carrying a can of tyre sealant can bring peace of mind but it is important that you spot the puncture early and stop quickly - running in a partially or fully deflated condition will cause weakening of the tyre structure and irreparable damage.

Permanent or temporary?

Puncture Repairs

Because a tyre has to be removed from the wheel and checked for internal damage before it can be repaired permanently, sealants can't be considered permanent repairs.

The standard for tyre repair also defines the materials and methods that can be used to repair tyres permanently. It states that the "use of liquid tyre sealants does not meet these criteria and hence cannot be considered suitable as a permanent repair."

Tyre experts recommend that you 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 in the tyre then it will have to be taken off the wheel rim and checked to see if it is suitable for a permanent repair.

Run-flat tyres

If you worry about getting a puncture, whether because of concerns about your personal safety or simply because of the cost and inconvenience of getting the tyre repaired, you might want to consider run-flat tyres next time you change your car. Test drive them first though as the ride may be firmer and tyres more expensive and harder to get repaired.

Run-flat tyres have either a reinforced sidewall or additional internal structure to provide partial support to the tyre in a deflated condition and are being offered by more and more manufacturers on new cars. If you do get a puncture in a run-flat tyre you might not notice, particularly on a motorway, because the ride quality will be very similar to normal. This is why run-flat tyres are always fitted together with a tyre pressure monitoring system (TPMS).

There will be restrictions on use following a puncture. The vehicle handbook will give details but in general deflated tyres should be capable of at least 50 miles (range can vary with vehicle load) at speeds up to 50 mph. Tyres should be renewed or repaired as soon as possible following a puncture.

You should get worn or damaged, run-flat tyres replaced by the same make of run-flat tyre. The TPMS will probably need to be reset after a new tyre has been fitted. Check the handbook for details.

Repairing run-flats

It is a basic principle of tyre repair that the repairer must inspect the tyre internally to check that it is safe to repair.

The repairer will consider the damage and condition of the tyre taking into account rules laid down in the appropriate standard (BS AU159f). These cover the position of the puncture in the tyre and the presence/extent of any secondary damage - damage that has occurred as a result of running in a deflated condition.

By definition, run-flat tyres are likely to have been driven 'flat' at speed for a considerable distance and this must be taken into account when considering the possibility of a repair.

The construction of run-flat tyres can make it difficult for the repairer to identify any secondary damage. This means that even though Run-flat repair kits are available to the trade, many repairers may be reluctant or simply refuse to repair a puncture in a run-flat tyre.

All tyre repairs can be carried out at our Witham Depot