What is a British Standard Tyre Puncture Repair?

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 1

Remove 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 2

Locate and mark the damage, taking out any foreign object still puncturing the tyre.

Step 3

Prepare 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 4

Repeat the process, now from the outside of the tyre inwards, ensuring once finished the channel feels resistance free on the mill cutter.

Step 5

Thoroughly 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 6

Hold the patch in position and mark its outline on the inner liner.

Step 7

Buff 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 8

Remove dust and extraneous material including wire particles, buffed rubber and fluffed cords.

Step 9

Apply a specialist vulcanising accelerator solution to the puncture channel and buffed area.

BSAU159 tyre repair step 9
BSAU159 tyre repair step 10 Step 10

Insert the combination tyre repair patch and plug into the puncture channel.

Step 11

Pull 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 12

Roll 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 13

Seal 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 14

Cut 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.

 

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>