According to statistics, drivers have a flat tire after an average driving distance of about 150,000 kilometers. So much for statistics, because they don't help in case of a puncture. Just like refuelling, punctures were normal in those days and nothing unusual. Punctures were not adventures like today. The spare wheels were even part of the outward appearance of an automobile, because they were usually mounted on the outside. But what happened to the spare wheel?

The spare wheel

The last place the spare wheel was installed was on, in or under the rear of a car. Over time, however, not only did the roads get better, also the rubbers. As a result, the tyre blowouts became less. Related to this also the desire and above all the ability to change wheels by yourself became less. Vehicle manufacturers considered alternatives and so a kind of „emergency wheel“ was born. It had the same functions as a spare wheel, but was much more space-saving and cheaper. In the meantime, this replacement has also come out of the „economic fashion“ of the vehicle manufacturers. Nowadays you hardly get a spare wheel when buying a new car. That costs extra. But the recess for the wheel is usually still there and is filled with styrofoam, a hazard warning triangle, a jack and a tyre sealant, usually with a compressor.

Photo: istockphoto.com

Photo: kmx24.de

Types of breakdown sets

The specialist and accessories trade offer a wide range of breakdown sets which is difficult to understand for the layperson. The alternative to the spare wheel is available in three different versions: as a spray, as a squeeze bottle and as a compressor system.The sealants consist largely of substances based on the natural material latex. Latex is the milk of the Ficus elastica, better known as the rubber tree.

Tyre sealant - tight or not?

If a tyre has been damaged during a puncture, the application of a tyre sealant is a good idea. The exact procedure is the same for all sealants. Each puncture kit contains a liquid sealant. The sealant must be applied by using compressed carbon dioxide from a can or compressed air from the compression chamber via the tyre valve to the inside of the tyre. The sealant is then distributed over the inside of the tyre, thus closing the punctured area. And here starts the problem - the provisionally functional tyre MUST be replaced with a new tyre. You will never get the sealant out of the tyre and additionally it does not guarantee absolute tightness. Another drop of bitterness - If your car is already equipped with a tire pressure monitoring system (TPMS - mandatory for all new passenger cars since November 1, 2014) and it is a direct measuring system with one sensor per tyre, the tire sealant will destroy the sensor and therefore it MUST also be replaced.

How can I avoid punctures?

The risk of a puncture can generally be reduced by regularly checking the tyres. Furthermore a tyre pressure monitoring system (TPMS) offers increased safety. The control system informs the driver of an acute drop in tyre pressure without delay. Run-flat tyres also offer a plus in safety. The run-flat properties of the tires allow the driver to continue a small stretch of road at reduced speed.

Tyre sealant

Pro:

• low tare weight
• low tare volume
• often favourable price ratio
• rapidly applicable

Contra:

• not a permanent solution because it is not an adaquate tyre replacement
• no universal solution for every type of puncture
• not applicable in the case of major damage to the tread
• not applicable for damage to the side wall of the tyre
• higher price level in individual cases
• only temporary
• Tire must be replaced
• TPMS sensor must be replaced
• Repair of the tyres afterwards not permitted in many European countries