Fixing a tyre

A punctured tyre is almost never a lost tyre. A nail in the tread is fixed in ten minutes at the roadside. Driving on it flat, on the other hand, kills it within a few hundred metres.

UNDERSTAND

What can be fixed: a hole in the tread, the part that touches the ground, up to about 6 mm. A nail, a screw, a shard.

What can't: the sidewall (the side), the shoulder (the curve between sidewall and tread), a long cut, a tyre that has been driven flat. The sidewall flexes on every turn: a repair won't hold there.

Driving flat crushes the sidewall between rim and road: it heats up and tears inside, and the tyre is scrap, even if it looks fine from outside. Stop as soon as you feel the car pull or thump. How a tyre is built is explained in The tyre.

ACT

Find the leak

• Look at the tread while rolling the car a few centimetres: a nail, a screw head, a shiny shard.
• Listen: a hiss.
• Soapy water brushed or poured on: bubbles where it leaks. Check the valve and the rim edge too.

Fixing a tubeless car tyre: the plug

A plug kit (a few euros in any car shop) makes the strongest repair you can do yourself.

1. Leave the nail in until you're ready: it's plugging the hole.
2. Pull it out with pliers.
3. Ream the hole with the kit's rasp tool, pushing it in and twisting several times: it cleans the hole and sizes it.
4. Thread a sticky plug string halfway through the eye of the insertion needle.
5. Push the needle in until only one to two centimetres of string stay outside.
6. Pull the needle out in one sharp move, without twisting: the string stays in the hole.
7. Cut off the excess flush, reinflate, check with soapy water.

It's a roadside repair: have the tyre checked by a professional as soon as possible, who will fit a patch from the inside.

The sealant can

It reinflates and plugs small holes in minutes. It gets you going, but it gums up the valve and the pressure sensor, and many garages then refuse to repair the tyre. Drive gently to the garage.

Changing the wheel

1. Car on flat ground, handbrake on, in gear, passengers well away from the road.
2. Loosen the nuts a quarter turn with the wheel on the ground, before lifting: otherwise the wheel spins in the air.
3. Put the jack on the proper point (a notch under the sill, shown in the manual), lift until the wheel clears the ground.
4. Unscrew, swap the wheel, screw on by hand, then tighten in a star pattern (one nut, the one opposite, and so on).
5. Lower the car, tighten fully. Retighten after 50 km (30 miles).

A narrow space-saver spare is limited to 80 km/h (50 mph) and meant for getting home.

Fixing an inner tube (bike, wheelbarrow, old two-wheelers)

1. Take out the tube, inflate it a little, find the hole (in water, bubbles; otherwise by ear or against your cheek).
2. Sand around the hole with the kit's sandpaper.
3. Spread the glue a little wider than the patch, and wait until it's dry to the touch, three to five minutes. It's everyone's mistake: a patch pressed onto wet glue won't hold.
4. Apply the patch, press hard for a minute.
5. Before refitting, find the cause: run your fingers gently around the inside of the tyre. A forgotten thorn punctures the new tube within a mile.

ADAPT

The tyre has come off the rim. To reinflate it, the beads must touch the rim. Tighten a ratchet strap around the tread: it squeezes the tyre and pushes the beads outwards. Wet the edges with soapy water, inflate, then release the strap as soon as the beads snap into place. The trick with petrol or spray set alight inside the tyre exists: it burns hands and bursts tyres, don't touch it.

A cut in the sidewall of a bike tyre. Slip a piece of old tyre, a folded energy-bar wrapper or a banknote inside, between tyre and tube: it stops the tube bulging through the slit, long enough to get home.

No patch left. For a bike: cut the tube at the hole and tie a knot with the two ends. The shorter tube goes back in and holds. For anything else: very tight tape, several turns, for a few kilometres.

No tube, nothing. Stuff the tyre with rope, packed dry grass, foam, old clothes: heavy and hard, but it rolls, slowly, to get you out of trouble. See Building a bike.

No compressor. A bike floor pump inflates a car tyre, with a few hundred strokes. A small 12 V compressor plugs into the cigarette lighter. A CO2 cartridge reinflates a bike tyre in two seconds.

A second-hand tyre found on a wreck: read its date (four digits after DOT, week and year) and look for cracks on the sidewalls. See Récupérer sur un véhicule.