Best fuel efficiency is one of the core requirements for commercial vehicles in India. Consequently it is a central challenge for commercial vehicle OEMs to optimize the entire powertrain, hence match engine, transmission and rear axle specifications best to the defined application.The very specific real world driving conditions in India (e.g. traffic situations, road conditions, driver behavior, etc.) and the large number of possible commercial powertrain combinations request an efficient and effective development methodology.This paper presents a methodology and tool chain to specify and develop commercial powertrains in a most efficient and effective way. The methodology is based on the measurement of real world driving scenarios, identification of representative Real World Driving Profiles and vehicle system simulation which allows extended analysis of the road topography, the traffic situation as well as the driver behavior. With such a setup realistic and reproducible driving boundary conditions can be applied to analyze the real performance differences of individual commercial powertrain parameters.As an example a 25t truck application is show-cased demonstrating a 3-7% potential of Fuel Efficiency improvement for typical Indian driving scenarios.The demonstrated methodology can easily be transferred to further development stages and used on test beds to perform the actual component load simulation online. Consequently this approach saves time and efforts especially when different powertrain parameters varied at the same time.