The 48-inch simple chassis dynamometer is a chassis dynamometer suitable for performance testing of passenger cars and light vehicles at speeds below 100km/h. It has high-precision and repeatable quality simulations. The use of a three-phase asynchronous motor positioned between the rolls ensures space saving, low performance loss and high torsional rigidity. It is used in front-wheel, rear-wheel and all-wheel-drive vehicles in single-axle and dual-axle configurations to ensure high dynamic stability of the front and rear axles. The modified system can simulate the road resistance with full electric inertia, reproduce the road resistance of the vehicle under test or customize the road resistance, and meet the dynamic, economic, regulatory and durability tests of the whole vehicle.