The tachometer indicates?

The tachometer measures the revolutions per minute (RPM) of the engine. This instrument is vital for drivers, especially in commercial vehicles, as it helps determine the optimal engine speed for various driving conditions. Monitoring RPM can aid in efficient gear shifting, ensuring the engine operates within its power band for better performance and fuel efficiency.

Understanding RPM is crucial for maintaining the health of the engine; operating at too high or too low RPM can lead to increased wear and tear or inefficient fuel consumption. This makes the tachometer a key tool for effectively managing engine performance in commercial driving scenarios.