What Is a Flywheel and How Does It Work?

Flywheels are found in almost all automobiles, performing an array of functions. A flywheel is typically made from cast iron, steel, or aluminum, and it is usually connected to the transmission side of the crankshaft. The section of the flywheel that faces the manual transmission is smooth and flat, allowing the clutch disc to grab onto it.

Overall, the flywheel is rigid in design and is equipped with a row of gear teeth that engage with the engine’s starter motor. The size of a flywheel depends on the number of cylinders and the construction of the engine. Beyond its design and location, what does a flywheel do?

Flywheels provide mass for rotational inertia, allowing the engine to run with ease. Without these mechanical devices, the engine stalls when you release the accelerator. More than that, it balances the engine by smoothing out the turbulence in the crankshaft. Additionally, flywheels allow for an electric starter to be used. When the starter motor engages the starter ring on the edge of the flywheel, engine rotation can begin. Of all the functions that the flywheel performs, the most important is connecting the engine with the transmission via a clutch to transfer power to the wheels.

Another function of flywheels includes the ability to stabilize engine speed. By smoothing out engine speed, the flywheel reduces wear and tear on drivetrain components. In addition, it reduces the wear between the transmission shaft and the driveshaft. Due to their versatility in terms of performance, there are many parts to a flywheel that play a role in their functionality.

Different Parts of a Flywheel

The first component of the flywheel consists of a solid housing that sits on the exterior of the assembly. The flywheel is also equipped with two-phase bent springs that are parallel in configuration. When the engine is operating, the outer arc raises the spring. The softer outer arc spring is tasked with improving the unprecedented resonance frequency range.

Next, a planetary wheel consisting of planetary gears is attached to the flywheel bracket. When the flywheel bracket is operated by a screw and rotates, the gears are set in motion. Flywheels, like most moving assemblies, are designed with bearings. Axial and radial sliding bearings can both be found in flywheels, assisting in weight distribution and rotation.

With the help of an interference fit, a ring gear is fitted on the outside of the flywheel. A support disc is affixed to the inside of the flywheel, supporting the springs and other components. There is also a flywheel sliding shoe that is usually positioned on the inner wall of the flywheel, minimizing wear for surrounding components. Lastly, a chrome-plated flywheel cover prevents contaminants and other pollutants from making their way into the flywheel.

Different Types of Flywheels

Beyond the parts that make up these versatile components, there are also varying types of flywheels.

Solid Disc Flywheel

This flywheel is typically made of cast iron and is equipped with a hub and disc. It is used in a single flywheel thresher.

Rimmed Flywheel

Highly sensitive when compared to a solid disc flywheel, rimmed flywheels explode at a very low  rotary speed. Rimmed flywheels have a low weight design and high energy-storage capacity. They can be made of high-strength steel and formed into a tapered disk that suits a number of applications.

High-Velocity Flywheel

The velocity of this flywheel is between 30,000 RPM to 80,000 RPM, but can be adjusted to reach 100,000 RPM. These flywheels are designed with magnetic levitation bearings and do not need frequent maintenance. When compared to low-velocity flywheels, they are compact in size and are lightweight.

Low-Velocity Flywheel

The last type of flywheel we will be covering is a low-velocity flywheel. With a velocity of up to 10,000 RPM, they are heavier and bulkier than the low-velocity variety. Moreover, they require maintenance and special concrete construction to support their weight.


If you find yourself in need of flywheels, bearings, support discs, or other various components, rely on Paragon Purchasing. Paragon Purchasing is the premier supplier of aviation parts, electronic components, IT hardware, and more, all of which have been subjected to a number of rigorous quality assurance measures to ensure their functionality and authenticity. Kickoff the procurement process with a competitive quote for your comparisons and see how Paragon Purchasing for all your operational needs.


October 23, 2020

Recent Twitter Posts

Semiconductor's Certifications and Memberships

Thank You for Visiting Us today!

We Hope You'll Remember Us the Next Time You’re Looking for NSN Parts.

Request for Quote

We use cookies to ensure that we give you the excellent experience on our website. If you continue to use this site we will assume that you are happy with it.