A bench testing apparatus for an automotive vehicle, comprises a rotary belt assembly including a pair of rotary drums arranged in parallel and spaced apart relationship to each other, a metallic endless belt extending over the drums and wrapped therearound, and a supporting structure disposed at a tread mounting section of the belt and oriented between the drums, the supporting structure including a rigid and stationary support base and a non-compressible fluid layer formed between the supporting base and the belt for acting as hydrodynamic bearing for the belt. A dummy load simulating vehicular traveling resistance, is associated with at least one of the drums. Also, a measuring device is provided for measuring driving torque exerted on the belt via a vehicular driving wheel. The tread mounting section being oriented for receiving a vehicular wheel tread for forming a testing surface to receive the driving torque.