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The Clutch: Giving Engines a Quick Break

If your car has a manual transmission, you’ll be making good friends with the clutch. Get on its good side by understanding how it works with Groupon’s study.

There’s a certain dance involved in changing gears in a car with a manual transmission. Take your foot off the gas, press the clutch pedal, move the gear lever, and gently release the clutch while reengaging the accelerator, all while checking the mirror to make sure your passengers notice how cool you look. But if that seems complex, it’s nothing compared to what’s going on behind that little pedal: an interconnected set of discs, springs, and plates bridging the engine and the transmission. This is the clutch, and its function is to either enable or prevent the engine’s transfer of power to the wheels.

When the clutch pedal is depressed, a piston releases the clutch plate from its usual point of contact, a flywheel that is spun by the engine. Breaking this connection effectively puts the car in neutral so that the driver can shift gears—otherwise, the gears on the input shaft from the engine and those on the output shaft to the driving wheels would grind together as this change was being made. Once the correct gear has been selected, the clutch is released, and the vehicle can continue at the desired speed.