Are the tachometer and speedometer different?

[Pam]

The tachometer and speedometer are different. The tachometer measures the rotational speed of the engine crankshaft, while the speedometer measures the vehicle's driving speed. The unit for the tachometer is rpm (revolutions per minute), and the unit for the speedometer is kilometers per hour. Every car engine has a relatively economical RPM range. When driving, if you can keep the engine speed within this reasonable range, it can improve the vehicle's fuel efficiency. During aggressive driving, it's necessary to delay gear shifts and allow the engine to reach higher RPMs, as this is when the engine can output greater power. However, the higher the engine speed, the higher the fuel consumption and the greater the wear. When driving in the city, it's rare to rev the engine high, and during highway cruising, there's even less need to do so. However, when overtaking, it may be necessary to increase the RPM. It is recommended that drivers avoid keeping the engine at high RPMs for extended periods, as this can accelerate engine wear.