Why does the Tesla Roadster have a two-speed transmission?
The Tesla Roadster has a two-speed transmission to maximize acceleration, while also allowing a reasonably high top speed. First gear gets you from 0 to 60 mph in under 4 seconds, while second gear takes you to 125 mph. The gearing of the Tesla Roadster works together with the shifter and the Power Electronics Module (PEM) to provide familiar driving behavior. First gear has strong “regenerative braking” that recharges the battery during deceleration and feels like engine braking in low gear on other sports cars. Second gear has less regenerative braking, and feels like third or fourth gear on other sports cars. The Tesla Roadster needs only two gears because the motor delivers high torque over a much wider range of rpm than any gasoline engine. No reverse gear is needed; the motor runs backwards for reversing. If you do not feel like shifting, you can drive entirely in second gear: acceleration even in second gear is remarkably fast.
