Bicycle: fixing a puncture and basic check

On most bicycles, the tyre holds an inner tube made of rubber that is filled with air. The air pressure makes the tyre firm and carries you. A valve lets air in but not back out. There are different valve types – for example the car-type Schrader valve, the slim Presta valve and the Dunlop or Woods valve. Your pump has to fit the valve, otherwise you cannot get any air in.

A patch seals the hole permanently if it is applied correctly. The vulcanising solution in the patch kit slightly dissolves the surface of tube and patch so that they bond firmly together. For that, the area must be dry, clean and roughened, and the solution must be left to dry briefly as stated on the pack. There are also self-adhesive patches that work without solution.

Many punctures have a cause that stays stuck in the tyre: a glass splinter, a small wire, a thorn. Another common cause is too little air. Then, on a pothole or a kerb, the tube can be pinched between the rim and the obstacle, leaving two small holes side by side. The right tyre pressure prevents many such breakdowns.

The quick check takes about two minutes and prevents many breakdowns. Tyre pressure: the recommended pressure is printed on the tyre sidewall. Press the tyre with your thumb – if it gives a lot, it needs air. A pump with a pressure gauge is more accurate than feel.

Brakes: pull both brake levers and push the bike forward. The wheels should not turn, and the levers must not pull all the way to the handlebar. Chain: it should be clean, lightly oiled and not rusty. A dry, squeaking chain wears quickly and makes riding hard work. A few drops of chain oil, wipe off the excess – done.

Lights: check the front and rear lights, especially when it gets dark early. Also check briefly that the wheels are seated firmly and quick releases or axle nuts are closed. A wheel that comes loose while riding is very dangerous.

Work in a safe place away from the road. Let all the air out and lever one side of the tyre off the rim with tyre levers. Do not use screwdrivers or knives for this – they damage the rim and tube. Pull out the tube, pump it up a little and listen for where air escapes. If you cannot find the hole, pull the tube through a bowl of water: where bubbles rise, that is the hole.

Before patching, find the cause. Carefully feel around the inside of the tyre with your fingertips and look at the tread. The position of the hole in the tube shows you roughly where to search in the tyre. Remove the object. Careful: glass splinters and wire can cut, so feel slowly.

When refitting, inflate the tube very slightly so it is round, insert it and push the last part of the tyre onto the rim by hand. Tyre levers easily pinch the tube at this point and make a new hole. Then pump to the rated pressure, refit the wheel and close the brake. On the road, a spare tube is often quicker – you patch the punctured one later at home at leisure.

After any work on a wheel, check before setting off: is the wheel seated firmly and centred? Are the quick releases or nuts tightly closed? Is the brake closed again and does it grip? A brake left open is one of the typical mistakes after patching. Then take a short, slow test ride.

Vulcanising solution is highly flammable. Do not use it near flames or cigarettes, do not breathe in the fumes and close the tube well. For roadside repairs, stand away from traffic; in the dark, lights and a hi-vis vest help others see you.

Some jobs belong in a workshop or need expertise: hydraulic brakes, suspension forks, adjusting brakes and gears, damaged rims or frames. With e-bikes in particular: you do not open the battery or electrics yourself. The manufacturer's instructions always take precedence.

Practise patching once at home before you need it on the road. Take a quiet afternoon, remove the wheel, take out the tube and put everything back together – even without a puncture. That way you learn how your bike is built, which tools you need and what type of valve you have.

Then pack a small repair kit: patches and solution, two or three tyre levers, a small pump with the right fitting and – if needed – the tool for the axle nuts. Check now and then whether the vulcanising solution is still liquid; opened tubes dry out over time.

Bicycle maintenance manuals, such as “Zinn & the Art of Road Bike Maintenance”, describe patching tubes and checking brakes and chain as basic skills. Many bike shops and clubs also offer repair courses or open workshops where you can practise with guidance.