Well, then two thirds of cars now come with a tire repair kit instead of a spare wheel. And while these kits aren't always popular with drivers, if your car has one, you'll need to know how to use it. If you get a puncture, pull over and stop as soon as you find a safe place, preferably away from traffic, apply the hand brake and switch your engine off and turn on your hazard lights if necessary. Now take a look at the puncture. Sealant kits will only fill holes up to about 4mm across. So if you've got a nail in your tire, that's fine. But if the tire's torn or the alloy wheel itself is damaged, you're going to need to call a breakdown service. You'll find your repair kit in the boot, it'll either be in the side panels or as here under the boot floor. Now it consists of two parts, the bottle of sealant and the compressor for pumping up the tires. If you do have an object like a nail in your tire, don't try to remove it. Just unscrew the valve cap and attach the sealant bottle. And once attached, the pressurized sealant will spread around inside the tire. On this Toyota, the air compressor for inflating the tires, is then attached to the back of the bottle. However, on many other cars, you'll need to unscrew the bottle and attach the air compressor directly to the valve on the tire. Now it's time to inflate your tire. So take the lead from the compressor and plug it into the cigarette lighter or 12 volt socket inside your car. Then start the engine. Now turn the compressor on and inflate the tire until it reaches the recommended pressure shown in your car's handbook. If the tire isn't inflating properly, try rolling the car forward a few metres to help the sealant spread around. If that doesn't work, you may still need to call a breakdown service. If you manage to repair the tire, well done, you can carry on driving. You'll need to stop a couple of miles down the road to check your tire pressures again. And remember, this is only a temporary fix. So drive gently and keep your speed below 50 miles an hour. When you get to a garage, remember that you'll need to buy a new can of sealant and a new tire, which tests every aspect of tire performance from wet braking to wear. So check our reviews before you buy. Click the links to find out our best buy tires. Read our guide to saving money on tires and find out which breakdown companies we recommend.