#TechTip: Flexplates vs Flywheels

Flexplates and flywheels are both vital components, but what are the differences?

Flywheels

Flywheels are generally used on manual transmission cars. If you’ve ever picked up a flywheel, you know they’re quite heavy, and there’s an important reason for that. They have 3 very important jobs, and those are:
1. To provide a surface for the clutch to grab- The flywheel is literally the surface that the clutch mates to. It is bolted to the output of the engine and it spins with the crankshaft.
2. To provide extra mass to help contribute to the rotational intertia of the engine- The reason flywheels are so heavy is because the increased rotating mass makes it easier to start a car from a stop without stalling. At the risk of more difficult starts, performance oriented individuals may choose to switch to an aluminum flywheel for weight reduction bro.
3. To provide gear teeth for the starter motor to engage to- All those pointy things on the sides? Gear teeth that engage with the starter to move the engine when you turn that key forward!

Flexplates

Flexplates are generally used in automatic transmissions, and they’re obviously much thinner and lighter than flywheels. These are what connect the output of the engine to the torque converter of the engine (basically the clutch of the automatic). The torque converter makes up for the mass that the flexplate doesn’t have.
Their main functions are to:
1. Connect the crankshaft to the torque converter
2. To provide gear teeth for the starter