A disc brake testing apparatus comprises operating means operable to operate pad moving means of the disc brake to urge pads of the brake towards the disc thereof. The operating means operable to urge the pads against the disc with a higher pressure sufficient to cause the pads to maintain constant contact with the disc and apply a significant braking force thereto. In order to simulate conditions which cause disc thickness variation, the operating means is alternatively operable to urge the pads against the disc with a lower pressure selected to cause the pads to make intermittent contact with the disc during each revolution of the disc.