When double clutching and shifting you can use the tachometer.

When double clutching and shifting you can use the tachometer.

• A. Tachometer
• B. Speedometer
• C. Odometer
• D. Gas gauge

Answer: (A)

The important idea here is that shifting smoothly with a manual transmission relies on engine speed. A tachometer shows the engine’s revolutions per minute (RPM), so you can time the clutch work and gear changes to keep the engine in a range that matches the next gear. This is exactly what you’re doing when you double clutching and shifting: you’re trying to rev-match so the gears engage quietly and smoothly. The tachometer gives you the feedback you need to know when the engine is at the right speed to engage the next gear. The other gauges aren’t about engine speed. The speedometer tells you how fast you’re going, the odometer tracks total distance, and the gas gauge shows fuel level. None of those indicate engine RPM, which is why they aren’t used to time a smooth shift.

The important idea here is that shifting smoothly with a manual transmission relies on engine speed. A tachometer shows the engine’s revolutions per minute (RPM), so you can time the clutch work and gear changes to keep the engine in a range that matches the next gear. This is exactly what you’re doing when you double clutching and shifting: you’re trying to rev-match so the gears engage quietly and smoothly. The tachometer gives you the feedback you need to know when the engine is at the right speed to engage the next gear.

The other gauges aren’t about engine speed. The speedometer tells you how fast you’re going, the odometer tracks total distance, and the gas gauge shows fuel level. None of those indicate engine RPM, which is why they aren’t used to time a smooth shift.