I have a 2010 Skoda Superb TDi 170 Elegance. Its standard wheels are 18-inch shod with 225/40 R18 tyres. With the advent of winter I bought a set of alloy wheels fitted with winter tyres. These wheels are 16-inch and the tyres are 215/55 R16s of suitable speed and load rating. The standard tyres for 16-inch wheels on the smaller-engined Superbs are 205s, but the 215s fit perfectly and, according to tables, seem to have a very similar rolling circumference to the 18-inch wheels. The difference is amazing.

The car rides and handles much better, especially on our atrociously rough roads, and, most surprising of all, fuel consumption has improved by well over 10 per cent to give me a remarkable average of around 52mpg (mostly out of town). Why is this? Come the spring I now plan to fit summer tyres of the same size to the 16-inch wheels, keeping the standard wheels in storage until I come to sell the car. Are there any snags in so doing?