The Original Concept Of A Bike Sprocket And Chain

By: Alex Bristol

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The Original Concept Of A Bike Sprocket And Chain

Looking to build a bike or even learn more about the bike you’re currently riding? What a better place to start than by learning about the concept of a bike sprocket and chain.

Well, I’m here to help!

The term ‘sprocket’ is a profiled wheel with teeth or cogs which mesh the chains. It applies to any wheel upon which radial projections engage a chain passing over it.

It works with the chain to essentially allow the bike to move, but let’s jump into more details!

What is the original concept of the bike sprocket?

When bikes were first invented, riders had to dismount the bike to change gears; the first design of the two-speed bicycle was that the wheel had a sprocket on each side of the hub.

To change the gear, the rider had to remove the wheel, flip it around and then mount back on the bike– talk about the hassle!

Early derailleurs even featured large mechanical levers to move the chain; between 1877 and 1906, 750 patents wanted variable speed gearing, but this was not commercially desirable.

So when was the sprocket invented?

It wasn’t until 1895 that Jean Louberyre designed a device that derailed the chain from one sprocket to another. Bike sprockets refer to the number of chainring teeth ratio to the number of teeth on the cassette cog.

 How a chain and sprocket wear together:

As the chain and sprocket wear together, the teeth become sloped at the back, and the rollers ride them until the teeth approach a radius that matches the longer pitch of the worn chain.

This causes the sprocket to become larger because the chain is riding higher. There is also excessive wear on the rollers; they have to roll more and press harder because the surface is not at the right angle to the direction of tension on the chain.

This downward force from the chain on top of the sprocket is greater and extends further back around the sprocket with sloped teeth. As a result of this, more teeth at the back of the sprocket push up to compensate for this downward force.

The sprocket will also wear at the height of the teeth, taking the load, and may even lift the chain completely off the sprocket and skip it forward.

Over time this wear and tear continue, and the tension increases until the chain slip off the teeth and jumps forwards; as this wear and tear continue, it will need to be replaced.

What are a chain and sprocket?

A sprocket (also known as either a sprocket-wheel or chainwheel) is a profiled wheel with teeth or cogs which mesh with a chain.

The name ‘sprocket’ refers to the wheel upon the radial projections which engage the chain passing over it; it allows the rider to change from gear to gear. Sprockets have teeth that attach directly to the chain.

How the chain engages the sprocket:

So what are the chain and sprocket? How do they work with each other within the bike frame?

Suppose the tension is pulling from the run of a chain on a rear sprocket and pulls horizontally from the sprocket’s top. The gap from the center of each roller of the new chain to the center of the next is roughly 1.2cm (this is also known as the pitch of the chain).

The chain is used to connect the two sprockets, one is called the drive sprocket, and the other is the driven sprocket. The motion and force can be transmitted via the chain from one sprocket to another and one shaft.

Chains are used to transmit motion and force from one sprocket to another– this is called power transmission chains.

Here’s how the chain wheel and the sprocket work together on a bicycle:

Input: Human effort rotates the crank, which is connected to the sprocket.

Process: Sprocket moves the chain

Output: The chain moves the sprocket connected to the back wheel on the bike, and the back wheel begins to rotate.

What is the purpose of the chain on a bike?

A bicycle chain is a roller chain that transfers power from the pedals to the drive of the bicycle’s wheel; it doesn’t propel it.

Most bicycle chains are made from either plain carbon or alloy steel, but you may see some made with nickel-plated metal to prevent rusting or make the bike look aesthetically pleasing.


All in all, the sprocket and the chain work together to help the rider change gear while they’re riding; they’ve come a long way since when they were first designed.

They have developed with complete ease, instead of having 2 gears and having to get off the bike to change gears, you can shift them using your hands, and there are so many gears to choose from in modern bikes.

The sprocket works by allowing the chain to pass over it to change gear and, therefore, an essential part of the bike.

Happy biking!