A spare tyre of a smaller size than the road tyres. The purpose of the reduced size is to save space and reduce weight. Designed to get you home, these tyres have a slower maximum speed and are designed to be used only on a temporary basis. These tyres have been banned in New Zealand. Certain cars, such as Porsche, feature an uninflated space saver spare accompanied by a small electric compressor. They are most useful on a car with staggered wheels, ie larger tyres on the rear wheels than on the front ones.