Space Saver Wheels & Tyres
The design of some vehicles is such that there is insufficient space available to carry a conventional spare wheel and tyre. In order to avoid the possibility of a tyre puncture or failure rendering such a vehicle immobile, the manufacturer usually provides a 'get you home', temporary-use spare unit, or a space saver spare wheel.
There are two types of space saver wheels. The more common of these is a wheel and tyre combination with a narrower width or cross section. The second type is one incorporating a special tyre which, when not in use, is carried deflated on the rim and thus occupies much less space than a conventional tyre.
The durability of space saver tyres is inferior to conventional tyres. Also, with dissimilar tyres fitted, the handling and controllability of your vehicle can become unpredictable. Vehicle manufacturers design their space saver wheels and tyres to compensate for any imbalance so you should only use space savers that are supplied or recommended by the manufacturer of your vehicle.
Space saver wheels and tyres should only be used in emergency situations and for as short a distance as possible. When your damaged wheel or tyre is repaired, you should put it back on the vehicle immediately.