An apparatus measures the tread of a tyre on a vehicle, in which a laser line generator (34) generates an elongate pattern of light. Mirrors (36) are arranged to reflect light from the laser line generator (34) onto the rolling surface of the tyre. Mirrors (36, 38, 42) are arranged to reflect light from different regions of the rolling surface of the tyre towards a camera (32). The camera images the regions of the rolling surface of the tyre. The apparatus may be hand-held or arranged such that a tyre to be imaged is driven onto or over it.
