Few household purchases are as opaque as a set of tyres. The Label Tells You Three ThingsEvery new tyre sold carries a standardised label rating three characteristics: fuel efficiency, wet grip and external rolling noise. Fuel efficiency affects running costs over the tyre’s life and can partially offset a higher purchase price. Valve replacement is a few pounds and matters, since an old valve on a new tyre is a common cause of slow deflation. Buying Two Rather Than FourMost people replace tyres in pairs rather than sets, and where they go matters.