The RIGHT and WRONG way to repair a punctured tyre.
The right way to repair a tyre puncture.
Waking up to find your car has a flat tyre is never good, especially if you have got the commute to work to contend with or a family road trip planned.
While almost any small object left on the road can cause a tyre puncture, sharp objects such as screws, nails and glass shards are the most common causes.
“Before agreeing to have any puncture repair carried out, make sure the tyre technician has removed the tyre from the wheel for a thorough inspection and that he or she intends to repair the tyre by the British Standard.”
Even though the damage may appear small, it is important to have the tyre inspected by an expert to ascertain the full extent of the damage, including whether there is any secondary damage caused by driving on the tyre at low pressure.
Assuming the tyre inspection does not find any tyre damage meaning the tyre should be replaced instead of repaired, two crucial aspects now need addressing in any subsequent tyre repair;
- Reestablishing the integrity of the airtight inner liner within the tyre
- Ensuring the path the object took through the tyre is filled
Of all the numerous tyre puncture repair options available, there are three that are used in by far and away, the vast majority of cases. Of these three, however, only one is considered industry best practice and a British Standard Repair.
That repair is the tyre repair using a combination tyre repair patch and plug (also known as a combi repair or mushroom repair).
Below shows an example of a proper combination tyre repair patch and plug repair, along with the two other common, incorrectly performed tyre repairs that are not British Standard.
CORRECT TYRE REPAIRThis type of a puncture repair is a combination tyre repair patch and plug (also known as a combi repair or mushroom repair). This type of repair achieves both the key points of consideration when correctly repair a tyre puncture. |
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INCORRECT TYRE REPAIR |
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This type of puncture repair is known as a string repair and does not reestablish the airtight inner liner of the tyre. |
This type of puncture repair is known as a patch repair and does not fill the path the object took through the tyre. |
Tyre repairs made externally, without removing the tyre from the wheel are never acceptable on modern car tyres. Without a proper inspection of the inside of the tyre, there could be any number of types of internal tyre damage that go unseen, therefore returning a tyre to the road that is unsafe.
Why a string or patch puncture repair is the wrong way
String type of puncture repair is designed to be carried out from the outside of the tyre, meaning the tyre can not have a complete internal damage inspection.
The second problem is that this type of repair relies on the stickiness of the string to hold it in place in the path created by the puncturing object. However, the pressure of the air within the tyre, that will usually be upwards for 32 pounds per square inch will constantly be trying to push the string back out. Who will win, stickiness or air pressure?
Finally, unless the string when inserted some the outside inwards, somehow manages to fill the entire puncture cavity created in the tyre’s inner liner, there will not be a truly airtight seal, and air will seep out around the string over time.
A puncture repair patch is installed from the inside, therefore allowing a thorough inspection of the tyre’s interior. It also fully reestablishes the tyres air tight properties by sealing over any part of the inner liner that is damaged. However, a patch type of puncture repair does not fill the entire puncture cavity, so allowing moisture in and causing the now exposed steel tyre cords to corrode and rust. Once it has begun, this rusting can spread from the original puncture cavity along the tyre cords to the sidewall where the increased flexing in the sidewall can cause the now brittle cord to snap, producing a weak spot.
This weakened spot in the tyre’s sidewall can then develop into a bulge due to the air pressure inside, which in the best case scenario will cause an MOT failure, or in the worse case scenario could cause a tyre blow out.
So, if your local garage offers to repair your punctured tyre in “just a few minutes”, for as little as £10; be wary. They almost certainly are not repairing your tyre to the British Standard.
The British standard repair is a complex multi step procedure that will take upwards of 20 minutes when done properly.