Abstract: A roller-type ultrasonic inspection device for inspecting vehicle tires comprises a roller assembly 20 mounted on a non-rotatable hug 16. Two piezoelectric crystals 80,82 are mounted in the hub 16 such that their principal transmitting/receiving axes A and B converge generally radially outwardly of the hub. The angle between the axes A and B is selected such that when the roller assembly 20 is urged into rolling contact with the tread-bearing surface of a tire 90, the axes meet (allowing for refraction effects) in the body of the tire beneath the tread. This ensures that the device can detect defects in the body of the tire, and is relatively insensitive to the tread.