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What Is A Flywheel And What Does It Do?

What Is A Flywheel And What Does It Do?

Ever heard someone talk about the flywheel in an engine and found yourself scratching your head?

Don’t worry! In this quick guide, we’ll explain everything you need to know!

What Is A Flywheel On A Car?

A car flywheel is a rotating mechanical device that is used to store energy, they are made of heavy-duty metals such as steel or iron and are mounted on the engine near the clutch.

The flywheel helps to keep the engine running smoothly by providing energy when needed and absorbing shock when the engine is under load.

The term ‘flywheel’ is usually used for manual transmission vehicles – whereas automatic transmission vehicles have a similar devices known as a ‘flex plate’ that connects with the torque converter in this transmission – helping the engine run smoother.

How Does a Flywheel Work?

A flywheel works by storing energy in its spinning mass and then releasing that energy when needed.

When the engine is running, the flywheel spins and stores energy. When the engine is under load, such as when you release the clutch pedal step on the gas pedal, the flywheel releases its stored energy through the clutch disc to help power the engine and turn the wheels.

The amount of energy that a flywheel can store as kinetic energy depends on its size and weight. The heavier the flywheel, the more energy it can store. This is why flywheels are made of heavy-duty materials such as steel or iron.

The flywheel actually also helps to start the vehicle too. The engine’s starter motor is fairly small – so it engages with the gear teeth on the outer edge of the flywheel and rotates it, giving additional rotational energy to create rotational speed to get the engine crankshaft moving.

What is a lightened flywheel?

Among car enthusiasts, you may hear people talking about lighter flywheels and the performance boosts they offer.

A lightened flywheels is more easily turned. As such, it doesn’t hold as much kinetic energy – but it does allow for quicker acceleration through a quicker increase in engine speed. As such, it’s a popular upgrade in race and rally vehicles – although not as popular in off-road vehicles, where additional torque is preferred.

Why Is A Flywheel Important?

Several benefits for your car, including:

  • Improved Engine Performance
  • Reduced Fuel consumption
  • Longer Engine Life

What happens when a flywheel breaks?

A flywheel is an essential part of engine operation – so if it goes wrong, you’ll find your car will not move. Don’t worry though, there are usually plenty of tell-tale signs that your flywheel might need attention long before this happens!

Since the flywheels spring mounts contribute to drivetrain stress reduction, you’ll sometimes notice some of this ‘stress’ (in this case, vibrations) becomes apparent as your clutch pedal vibrates as you drive and change gear. This is because the clutch pressure plate is moving slightly – rather than being held against a solidly mounted flywheel.

What Is A Flywheel And How Does It Work? Conclusion!

If you’re wondering what that big metal disc attached to your car’s engine is, wonder no more! That’s the flywheel, and it’s an important part of how your car runs.

The flywheel helps to keep the engine running smoothly by providing energy when needed and absorbing shock when the engine is under load. So next time you’re driving, remember to thank your trusty flywheel – an often forgotten part of the engine!

Think you’ve got a problem with your car’s flywheel? Don’t worry – Auto Hero will connect you with workshops near you that can diagnose and fix all kinds of engine and transmission problems!

Flywheels Repairs


Written By

Matt Banks

Matt is the founder of Autohero.com.au and has been hooked on cars and repairs ever since childhood. A veteran in automotive since leaving school, Matt has completed his trade as a panel beater and is across all things with wheels. 

His first car was a 1967 FORD XR Wagon followed by a string of collectable Holden’s.

Have a question for Matt? leave a comment below.

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