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What is a British Standard Tyre Puncture Repair?

BSAU159 tyre repair step 11

There are various methods of repairing a punctured tyre, with numerous accompanying products to enable those repairs.

By far the three most common tyre puncture repair methods are;

  1. An external repair using tyre string
  2. An internal repair using a repair patch
  3. An internal repair using a combination repair patch and plug.

However, only a tyre repair using a combination tyre repair patch and plug (also known as a combi repair or mushroom repair) is regarded as Industry best practice, as this is the only one to seal the tyre throughout the entire damaged area.

As for the actual repair procedure, there is only one that is accepted by British Standard Institution. This tyre repair procedure is known as BS AU 159 and sets out the "specification for repairs to tyres for motor vehicles used on the public highway".

British Standard Tyre Repair Procedure

Step 1Remove the tyre from the wheel and have a tyre expert thoroughly inspect it both internally and externally. If any serious tyre damage is present, then the repair should not continue. BSAU159 tyre repair step 1
BSAU159 tyre repair step 2 Step 2Locate and mark the damage, taking out any foreign object still puncturing the tyre.
Step 3Prepare the puncture channel from the tyre inside of the tyre using a 6mm carbide mill cutter. BSAU159 tyre repair step 3
BSAU159 tyre repair step 4 Step 4Repeat the process, now from the outside of the tyre inwards, ensuring once finished the channel feels resistance free on the mill cutter.
Step 5Thoroughly clean an area 10mm to 20mm larger than the repair patch using a specific pre-buff cleaner and repair scraper. Make sure to remove all residues such mould releasing agents. BSAU159 tyre repair step 5
BSAU159 tyre repair step 6 Step 6Hold the patch in position and mark its outline on the inner liner.
Step 7Buff the inner liner to roughly 5mm beyond the marked area using an appropriate domed buffing rasp. Make sure that any raised ribs are left flat after buffing, leaving suede finish. BSAU159 tyre repair step 7
BSAU159 tyre repair step 8 Step 8Remove dust and extraneous material including wire particles, buffed rubber and fluffed cords.
Step 9Apply a specialist vulcanising accelerator solution to the puncture channel and buffed area. BSAU159 tyre repair step 9
BSAU159 tyre repair step 10 Step 10Insert the combination tyre repair patch and plug into the puncture channel.
Step 11Pull the combination tyre repair patch and plug outwards until the entire patch is flush with the inside of the tyre. BSAU159 tyre repair step 11
BSAU159 tyre repair step 12 Step 12Roll the reverse of the patch using a corrugated tyre stitcher. Roll from the centre of the patch outwards to remove any air bubbles, making sure the entire patch has solid contact with the buffed inner liner.
Step 13Seal the combination tyre repair patch and plug base and buffed area still exposed with an inner liner sealant. BSAU159 tyre repair step 13
BSAU159 tyre repair step 14 Step 14Cut the stem of the combination tyre repair patch and plug flush with the remaining tread of the tyre, after first mounting the tyre back onto the wheel and reinflating to the correct pressure.

 

British Standard Tyre Repair Rules

  • Tyre repairs for cars and vans are only permitted in the central 60% to 70% of the tyres nominal width (known as ‘Area T’), with this percentage differing as shown below, depending on the size of the tyre.
Repairable Percentage Area (‘Area T’) based on Nominal Section Width
Up to and including 155mm 60%
Between 155mm and 200mm 65%
Above 200mm 70%
Example - Tyre size 205/55R16;

 Nominal section width = 205mm

70% of this width = 144mm

This tyre is repairable within 72mm of either side of the tyre centre line.

  • The maximum diameter of the penetration hole left by the puncturing object is 6mm.
  • Repairs in Area T must not overlap one another.

NOTE: All the information on this page is relevant to what is considered a minor repair to a radial construction tyre fitted to a car and van. This information is not relevant to commercial vehicles, heavy plant or industrial vehicles. Major repairs such a repairs to sidewall damage are also governed by the same British standard but will need to be sent away to a specialist major repairer.

 

The RIGHT and WRONG way to repair a punctured tyre.

tyre-puncture-patch-repair

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;

  1. Reestablishing the integrity of the airtight inner liner within the tyre
  2. 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 REPAIR
This 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.

types-of-tye-puncture-repairs

INCORRECT TYRE REPAIR
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

tyre-string-repairstring 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. tyre-puncture-patch-repairHowever, 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.

Do I Need High Performance Tyres?

UHP-high-performance-tyre-thumb

UHP-high-performance-tyre-hero

Choosing the right tyres to suit your driving needs, your vehicle and the areas you tend to drive in can seem a daunting task. There are a wide variety of different tyres, all of which are designed for a specific purpose and because of this, different types of tyres have different advantages and disadvantages.

Many motorists are drawn to high performance tyres, however, they are not suitable for all vehicles or motorists. Take a look at our guide to see if high performance tyres are right for you.

What are High Performance Tyres?

High performance tyres have been designed to drive comfortably at high speeds and provide agility and exceptional handling capabilities. These tyres have been designed with an innovative tread design and a large contact patch to provide impressive griping capabilities, so that they can offer stability at high speed and when cornering.  Popular high performance tyres include the Goodyear Eagle F1 Asymmetric 2 and Continental SportContact 6.

The benefits of high performance tyres include:

  • Shorter stopping distances
  • Precise steering
  • Increased cornering stability
  • Enhanced grip

Will High Performance Tyres Suit Me?

Firstly, high performance tyres are best suited to high performance vehicles. Sports style cars will benefit from this type of tyre as they are both designed with the same purpose in mind: a sporty and dynamic driving performance.

If you are looking for tyres that maximise speed and performance, high performance tyres are probably the most suited for you. It is important to bear in mind, however, that high performance tyres will not offer the most fuel efficient performance, they are usually expensive and their tread may wear more rapidly. If efficiency and value are what you look for in tyres, you may wish to consider other tyre options.

What Other Tyre Options Do I Have?

If you feel that high performance tyres are not the best fit for your vehicle or driving style, there are plenty of other tyre choices available.

Touring Tyres

Touring tyres, such as the Turanza range from Bridgestone, offers a balanced performance with high levels of comfort, ability to drive at speed and good tread wear. Touring tyres are not usually designed to enhance performance levels specifically, but offer a good all-round performance.

Eco-Friendly Tyres

Eco-Friendly tyres, such as the Michelin Energy Saver, have been constructed to offer a more environmentally friendly performance. Designed to allow lower rolling resistance, eco-friendly tyres require less fuel to move which means lower fuel costs and they reduce the production of harmful emissions. This is the primary function of eco-friendly tyres and they are not optimised to provide high performance at speed.

Buy new tyres online from Dexel Tyre & Auto Centre

Alternatively, if you require more advice on which tyres are best suited for you, contact your local branch where one of our tyre specialists will be happy to answer any queries you may have.

Stay Safe This Tyre Safety Month

check-your-tread

Every October, TyreSafe run a ‘Tyre Safety Month’ campaign designed to keep you safe on the road. The purpose of the campaign is to raise awareness of the importance of tyre safety and to encourage motorists to regularly check their tyres to ensure they meet legal requirements.

Legal Minimum Tread Depth

Tyre tread is the rubber that covers your tyre and makes contact with the road. A new tyre will begin its life with 8mm of tread, but over time this will wear down due to general driving wear and tear. There is no time frame for tyre tread wear, so it is important that you check yours every three weeks to ensure that they remain above the legal minimum depth of 1.6mm.

Legally, your tyres must maintain a tread depth of at least 1.6mm throughout a continuous band, including the central three-quarters of breadth in the tread and its entire outer circumference.

How to Check Your Tread

Checking your tread depth is a simple task and can be undertaken easily at home using a 20 pence coin. Simply use the coin to indicate how low your tread is by placing it in the grooves of your tyre and checking to see that you can still see the outer band of the coin. If you can see this part of the 20 pence, your tread depth is low and could be illegal. You should replace your tyres at this point.

check-your-tread

The Dangers of Driving on Illegal Tyres

Driving on tyres with 1.6mm is highly dangerous and poses a huge threat to the safety of yourself, your passengers and other road users. Dexel Tyre & Auto Centre would recommend replacing your tyres once they reach 3mm, as at this point your safety on the road is drastically affected.

Tyre tread is designed to provide the tyre with grip so that it can maintain contact with the surface of the road. The more tread your tyre has, the greater your gripping abilities, so when tread decreases so does your braking capabilities and wet weather performance.

Driving on illegal tyres could be highly dangerous in wet conditions, as tyre tread provides resistance against aquaplaning. When you aquaplane, water on the surface of the road causes your tyre to lose contact with the road, making it difficult for you to control your vehicle. Tyre tread works to evacuate water from the tyre and maintain contact with the road surface, reducing your risk of aquaplaning.

According to a recent survey from TyreSafe, there have been over 5,677 casualties over the last five years, resulting in 989 people being seriously injured or killed due to tyre related incidents*.

If You Get Caught Driving on Illegal Tyres

As well as being extremely dangerous, driving on tyres with tread lower than 1.6mm is illegal and if caught you will face 3 penalty points and a fine of up to £2,500 per illegal tyre. In addition, if you were in an accident, whether your fault or not, your insurance may be invalidated if you were found to be driving on illegal tyres.

Stay Safe

Don’t take the risk – check your tyre tread every three weeks and contact a tyre specialist if you require further advice or find cause for alarm. When your tyres reach 3mm, Dexel Tyre & Auto Centre would recommend replacing them.

*http://www.tyresafe.org/campaigns/tyre-safety-month-2016-2/2016-campaign/

When Do I Need New Tyres?

new-tyres-tread-indicators

The condition of your tyres has a huge impact on your vehicle’s performance on the road. Tyres control your braking distances, gripping capabilities and keep you safe in wet conditions so it is important that you look after them properly and know when it is time to replace them.

Over time, tyres will need replacing due to everyday wear and tear. Think you may need to replace your tyres? These are the signs to look out for:


Your tyres have worn out

Tyres are designed to grip thnew-tyres-tread-indicatorse surface of the road, resist aquaplaning and ensure that you brake safely. As your tread depth reduces, however, so will your tyres' capabilities.

Once your tyre tread depth is lower than 3mm your tyres’ capabilities will be significantly reduced and any lower than 1.6mm is illegal. So you must have you tyres replaced when the tread falls between these depths.

You can roughly check your tyre tread depth at home using a twenty pence piece, as shown in our guide. Tyres also have tread wear indicator to show when your tyres need replacing, like on this Michelin tyre.


Your tyres are cracked

new-tyres-cracked

Large cracks in the sidewall of your tyre can be dangerous. If you notice any, you should replace your tyres as soon as possible. There could be damage to the internal structure of the tyre, which may mean it is close to a blow-out.

In addition, little cracks all over the tyre may mean that the rubber is breaking down and could be susceptible to falling apart. This could also be highly dangerous if ignored so you must have this looked over by a specialist or replace your tyres as soon as possible.


You notice lumps, bumps or bulges

new-tyres-bulges

Lumps, bulges and bumps on the surface of the tyre are all signs that the structural integrity of the tyre has been compromised.

This weakening of the internal structure of the tyre means the tyre may no longer able to support the load of your vehicle, and if put under continued load could lead to a dangerous blow-out.

This type of tyre damage, unfortunately, cannot be repaired.


Your tyres have a puncture

flat-car-tire-wood-screw-imbedded-tread-closeup-horizontal-photo-embedded-40921039 Most punctures can be repaired as long as the puncture is within the central ¾ of the tyres tread, and no additional structural damaged has been caused.

Even if a tyre specialist says your punctured tyre is repairable, it is worth considering your tyre's condition. If it is fairly worn, it might be more economical to simply replace it a little early.

 


For further advice on tyre safety or if you would like to have your tyres checked over by a specialist, contact your local Dexel Tyre and Auto Centre branch.

Alternatively, you can purchase new tyres easily online. Simply search for your tyre size and select the tyres of your choice. You can then either purchase online, or reserve and collect, and arrange a fitting at your local branch at a time to suit you.