Tyre Repairs - What you need to know
How do I know if I have a car tyre puncture?
There are several signs to look out for if you believe you may have a puncture but your tyre is not yet flat, these are:
- Steering may become difficult, this is usually due to the tyre slowly deflating because it has sustained a slow puncture
- The car may feel wobbly or shuddery when driving
- The car may pull to either the left or the right side depending on what side the puncture is on
- If the tyre has a nail or screw in it, you may hear a ticking noise as this makes contact with the road as the tyres rotate
Are puncture repairs safe?
There are certain recommendations set by the British Standard BS AU 159 that must be adhered to for a puncture repair to be carried out safely. They define limits to the location, size and number of repairs that can be carried out on a tyre. To meet these recommendations and adhere to the safety guidelines, we will only repair a puncture sustained in the ‘minor repair area’ which is the central ¾ of the tyre. If the tyre has a puncture anywhere outside of this area, we cannot safely repair this section as it is too close to the sidewall. Additionally, if a puncture is over 6mm in diameter, regardless of whether it is in the safe area or not, we cannot repair this as the damage is too big for a safe repair.
The British Tyre Manufacturers Association (BTMA) representing the Tyre manufacturing industry in the UK, work in association with Tyresafe.org who actively promote road safety and as such the BTMA expect tyre technicians to adhere to the British Standard when carrying out puncture repairs.
Therefore, here at National Tyres we will not carry out a ‘string’ repair. A string repair involves repairing a puncture from the outside of the tyre. This is deemed unsafe as the technician will not be able inspect the internal damage of the tyre caused by the puncture and is not an approved British Standard BS AU 159 repair.
Is my puncture repairable?
This will largely depend on where the tyre sustained the puncture, what it was punctured with, the condition of the tyre and the speed rating.
A tyre can only be repaired if it is a small puncture (less than 6mm in diameter) in the central ¾ of the tyre, anywhere else is deemed unsafe as it is too close to the sidewall.
Other factors to take into consideration are what the tyre was punctured with and the general condition of the tyre. If it was a small object such as a nail or a screw that caused a small puncture, and the damage is in the central ¾ of the tyre then it would be possible to repair the puncture.
However, if the tyre is showing any sidewall damage or there is visible bead wire or the rubber is distorted and cracking then the tyre cannot be safely repaired and will need replacing.
Any tyres rated ‘V’ and above can only have one puncture repair in the lifetime of the tyre.
Related: How to read a sidewall
Can all punctures be repaired?
Unfortunately not, the image below shows the red T area that can be repaired if punctured, anything outside of this is not repairable for safety reasons.
In the interest of safety and by the guidance of the BS AU 159 National Tyres and Autocare will not repair a tyre that exhibits any of the following:
- Tread depth which is below the legal limit.
- Damage to the tyre such as splits and cuts in the rubber
- Damage to the casing – the internal structure of the tyre
- Repairs previously done to the tyre not in-line with the British Standard
- A significant solvent contamination
- Damage to the bead of the tyre
- Deterioration to the liner of the tyre
- Damage caused to the tyre from under / over inflation
- Cords exposed from tread wear or sidewall damage
In case you are uncertain about whether your car tyre must be repaired or not, seeking expert advice is a must.
How much is a puncture repair?
At National a puncture repair will include a new valve and wheel balance to ensure the safety of the tyres before you leave the premises. This will cost £25.00 per tyre. We recommend that tyres are re-balanced after being repaired as the wheels have been removed from the car and will need to be set to ensure the weight of the wheels turn evenly as the tyres rotate.
Puncture repair kits work by forcing a sealant through the valve into the tyre and a compressor which is provided in the kit then inflates the tyre. The compressor runs off the 12-volt power source outlet provided by the cars battery. The punctured hole is sealed when it is coated from the inside. Once sealed, the tyre should only be driven at a reduced speed, not exceeding 30mph. At your earliest opportunity, you should seek a professional repair to the tyre.
Puncture repair kits only work if the tyre has suffered a minor puncture, blow out’s – sudden and immediate loss of the air in the tyre causing structural damage cannot be repaired by a puncture repair kit. Damage caused to the sidewall from hitting a kerb will also prevent a puncture repair kit from working. In these instances, the tyres will need replacing as it would not be safe for even the most experienced technicians to repair them.
Puncture repair kits include a bottle of sealant and a compressor to inflate the tyre. There are a couple of different types of sealant; water based foam sealant and latex sealants. Here at National we will repair a tyre, providing it is safe to do so, that has been repaired with a water based sealant. This is because water-based sealants can be removed from inside of the tyre easily and do not leave any permanent damage meaning it can be repaired safely.
Tyres are the only part of the vehicle which is in contact with the road and are therefore one of the most important parts in terms of safety. If you sustain a puncture National would always recommend that you allow one of our skilled, experienced and certified technicians to carry out a puncture repair for you.
Not only will our technicians ensure that the tyre is repaired to British Standard BS AU 159 but they will also be able to check the general condition of the tyre ensuring it is balanced, aligned and the pressure is accurately set before sending you on your way.
If your tyres appear to be losing pressure but there are no visible signs of a puncture i.e. a screw in the tyre, then it is possible you have a leaky valve. To check for this, inflate the tyre then rub soapy water around the valve. If the valve is leaking air bubbles will form confirming that the valve is leaking and a replacement valve is required.
Losing pressure in your tyres not only poses a safety risk as underinflated tyres have less grip on the roads but it also increases your fuel consumption. Your car manual will advise of the correct pressures for your tyres. Tyre pressure is expressed as either PSI or BAR.
Although some punctures are unavoidable there are still a number of checks you can carry out yourself to try and minimise the risk. The first, most obvious one is to try and avoid driving over debris in the road. It is also advisable that you regularly check your tyre treads for cracks and to ensure that the treads are within the legal limit and that the tyres are set to the recommended pressures. Driving on worn treads is dangerous and underinflated tyres can lead to blow outs as the tyres are susceptible to punctures because they have less air to absorb impacts from uneven road surface’s and kerbs.
Try to avoid bumping the kerb. If you do strike the kerb it is likely to be with the sidewall of the tyre which is much thinner than the central belt where the treads are thicker and the damage caused would be unrepairable. If you are lucky enough not to damage the sidewall, you would need to check the valve as this is positioned on the side of the tyre and could have been damaged in the impact leading to a slow puncture.
Don’t overload your vehicle, this puts enormous pressure on your tyres which can lead the tyre to bulge under the weight causing it to bounce when driving at speed increasing the chances of a puncture or in more serious cases a blow-out.
Tyres that have suffered a puncture are perfectly safe to repair providing the condition of the tyre has been evaluated by an expert and that the puncture was sustained in the central ¾ of the tyre which is considered the safe area.
A puncture repair is not considered safe if the tyre has visible damage or has sustained damage to the internal casing.
Driving on a punctured tyre can cause internal damage to the tyre as well as the wheel so it is best to get it fixed as soon as possible.
The options available to drivers with a punctured tyre are:
- Use a puncture repair kit to temporarily seal the puncture and drive slowly and safely to one of our expert technicians.
- Alternatively, you could swap the punctured tyre for the spare then bring the punctured tyre into one of our branches for a repair or replacement depending on the size and location of the puncture.
*We recommend that you frequently check the air pressure of the spare tyre as driving on an underinflated tyre is dangerous and could lead to a puncture or blow-out.
The British standard (BSAU159) has set regulations which tyre technicians must adhere to these. These regulations state that tyres can only be repaired in the central ¾’s of the tyre where the tread is at its thickest. If the tyre is V rated or above and has had a prior repair, this tyre cannot be subsequently repaired.
The puncture needs to be less than 6mm in diameter otherwise it is not safe to repair it.
Tyres that have sustained a puncture near the sidewall cannot be mended. The process of mending a punctured tyre requires the tyre to be removed from the wheel and deflated and the repair is carried out using an air drill which can weaken the sidewall as it is made of softer materials than the central tread. Additionally, a puncture is repaired using a repair patch which needs to stick to the hole to block the air from escaping and deflating the tyre, the sidewall of the tyre is the most flexible and the movement in this area could cause the patch to come off. The sidewall of the tyre carries the majority of the load when you are driving so you need this area to be as strong as possible.
While it is possible to repair a puncture in a tyre that has already been mended, there are several factors which will dictate whether this can be done safely. As with a first time repair, the factors affecting an additional safe repair are location of the puncture and condition of the tyre.
However, tyres that are rated V and above cannot be repaired more than once. This is due to the fact that tyres which are rated V and above are usually fitted to cars that are capable of high speeds in a very short space of time, once a puncture has been repaired the tyre, although safe is slightly weakened.
When purchasing tyres at National Tyres and Autocare we offer an accidental impact damage guarantee. If a tyre sustains a puncture during the lifetime of the guarantee, the tyre will be repaired (if safe to do so) free of charge and to the British Standard BSAU/159.
Runflat technology was engineered to allow vehicles to continue to drive for a short period in the event of a puncture. These tyres have reinforced sidewalls meaning the damage sustained by a puncture is often masked. Therefore these tyres cannot be repaired as we cannot guarantee the safety of these tyres once they have been repaired and left one of our branches. Unfortunately, if a Runflat does sustain a puncture it will need to be replaced.