How to: Puncture Repair

Valve Types

Presta (High Pressure) Valve

puncture2These valves are common on road bikes which have narrow tyres requiring a high pressure. To let the air escape unscrew the barrel and press the end. Don’t forget to screw the barrel back in when you have finished inflating the tyre.

Schrader (Car Type) Valve

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Schrader valves are mainly used on low pressure mountain/hybrid bikes which use fatter chunkier tyres.

To let air escape press the inner nipple.

Wheel Removal

Nutted wheels: Turn the nuts counter-clockwise to loosen them. There should be a washer between each nut and the fork end. If the washers are serrated the teeth should press against the fork end.

Quick-release wheels: Pull the handle straight out away from the bike and flip it over to release the tension on the quick-release skewer. Loosen the mechanism a bit more until you can get the wheel out.

Rear wheel removal: (1) Release the brake to let the brake shoes open up wide enough to fit the tyre through. (2) Shift the rear derailleur to the smallest sprocket. (3) Loosen the quick release or axle nut. (4) Pull the upper part of the rear derailleur backward and hold it out of the way. (5) Lift the wheel forwards and upwards to remove

Repairing the puncture

(1) Remove the tyre (one side only)

puncture6Carefully insert the tyre lever to release the bead of the tyre from the rim being careful not to nip the inner tube and hook the lever onto a spoke.

Move down two spokes and insert a second tyre lever and then two spokes again for the third. You can then start to ease one of the levers around the rim to release the tyre.

(2) Remove the tube

When the tyre is released on one side you can then get access to the inner tube.

(3) Check the inside of the tyre

Have a look around the inside of the tyre, there is usually a reason for a flat!  Do not run your fingers around the inside of the tyre as there may be glass, thorns or nails still embedded in the tyre.

(4) Slightly inflate

Attach a pump on your tube and slightly inflate.

(5) Identify the hole

It should become apparent where your tube has a hole.  If not try immersing it in a bucket of water and look for bubbles of air.

(6) Roughen the surface of the tube

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Roughen the surface of the tube using an abrasive.

(7) Apply a thin layer of adhesive

Apply a thin layer of rubber solution slightly larger than the patch you are using. Allow the solution to dry – it will be dry when it has a matt finish – approximately 2 minutes.

(8) Apply the patch

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This is a typical patch with a foil back. Peel the foil backing away and apply the patch to cover the hole. Press hard and make sure that there are no loose edges.

Remove the cellophane cover is optional. Most puncture repair kits have some chalk to stop the tube sticking to the inside of the tyre, so scrape some on if you have excess glue around the patch.

(9) Reinsert the tube into the tyre

Put a small amount of air into the tube before reinserting it to avoid kinks. Insert the repaired tube into the wheel starting from the valve. Carefully feed the tube inside the tyre.

(10) Pop the tyre back onto the rim

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When the tube is in place gently ease the tyre back onto the rim being very careful not to pinch the inner tube.

(11) Inflate to the correct pressure

When the tyre is sitting on the wheel correctly pump it up to the correct pressure (this pressure is stamped on the side of the tyre).

(12) Finally!

Put the wheel back onto the bike making sure that it sits squarely in the frame. Reattach the brakes and make sure that everything is running smoothly.