Based on the working conditions of Shanghai standard road driving cycle, the load spectrum for the key components of wheel deceleration system was extrapolated.According to the strengthening effect of low amplitude loads, the running-in test specification for the reducer system was issued.A durability test specification was developed based on the Miner rule and the deceleration system durability mileage was estimated.The bench test for durability shows that the prototype design satisfies the durability mileage requirement, and the bending fatigue strength of the gear is of sufficient reliability, which gives the possibility for further light weight design.Under the prerequisite of assuring the reliability and durability requirements, the method can be applied in the light weight design of other key automotive components.