Spare wheels could become a thing of the past, if BMW's example is anything to go by. A spokesman for GoodYear tyres, speaking at the recent launch of its HydraGrip mid-priced tyre, said that the German manufacturer will not fit spare tyres, or even spare-wheel wells, on future models, relying instead on run-flat tyres or cans of tyre-repair foam. Already, BMW's Z4 roadster is unavailable with a spare wheel. The move will save weight, should increase luggage capacity, and is likely to cut costs - to the manufacturer, at least. On average, a car suffers a puncture approximately once every 100,000 miles of normal driving, or around once every 10 years.