Kenworth News

Powertrain Optimization

There are several elements to keep in mind when selecting the desired Powertrain (PT) Optimization Goal. There are four different PT Optimization Goals to choose from: Performance, Balance, Fuel Economy and Downsped Economy.  

To obtain the best out of the selected goal, it is required that the Typical Operating Speed fall under the selected goal's RPM range, which can be found in PremierSpec when selecting the Rear Axle Ratio as shown in the illustration below. 

Also, a quick calculation can be done to check if the RPM falls under the goal's range with the selected Rear Axle Ratio and Typical Operating Speed:

Engine RPM = (Transmission Top Gear Ratio) x (Tire Revs per Mile) x (Operating Speed) x (Rear Axle Ratio)

If the RPM does not fall within the goal's RPM range, try choosing a different Rear Axle Ratio or Typical Operating Speed. You may also contact the Sales Engineering team for assistance at or at (425) 828-5999.