How Bicycle Gear works | Simple and Detail explanation

Knowing the mechanism behind the working of bicycle gear can help you choose the best suitable bicycle option with gear that suits your needs and budget as well. To understand the bicycle gear, first one should familiarize himself/oneself with a different part of the drivetrain which together called a drivetrain. 

 

Different parts of Bicycle Gear 

If you are already aware of different gear parts, you can switch to the next section of the blog on how the gear system works.

Chainwheel / Crank - The cycle crank mainly refers to the section of the drive train adjacent to the pedal for the chain to pass through. When pressure is applied to the pedal, the chain wheel rotates the chain on the attached crank and supplies mechanical energy to the chain.


Cassette / Freewheel - When the chain starts moving over the front crank, it transfers energy to the chain, which in turn starts pushing the rear sprocket to move. These sprockets are attached to the rear wheel, resulting in the rotation of the rear wheel.

Gear shifters -  These are attached to the handlebar. When you wish to change gear, you press the shifter, which internally pulls the metal wire and forces the derailleur to move horizontally, pushing the chain to move onto different teeth on the front crank or rear cassette.

Derailleur - This is the part of the gear system used to move the chain onto different sprockets on the front crank or rear cassette area. When you press the gear shifter on the handlebar, the wire attached from the gear shifter to the derailleur gets pulled which in turn moves the derailleur horizontally pushing the chain to switch gear.

How Does Bicycle Gear System Work?

The amount of energy you apply to push the pedal gets converted into rotational energy by the drivetrain mechanism. One can consider the legs as the engine of this two-wheeler, which helps to move the cycle forward.

Since this engine or pedaling effort, is operated by human-powered leg strength, it is not feasible to apply the same strength all the time, considering different terrains like flat or uphill roads, or continuous pedaling for long hours. Hence, gear mechanisms help reduce the effort of pedaling so one can continue to pedal and move forward with less strength applied by the legs.

But this lower leg power required to pedal comes at a cost. As less pedal strength is needed, the number of pedal rotations will increase as well to cover the same distance. Since it is easier to pedal multiple times with less power to continue moving compared to either applying constant power or taking a stop to regain strength in the leg, the gear helps you keep moving and attain better average speed.

One can also Image the gear bicycle mechanism by relating it to a gym cycling machine where you have a knob to reduce or increase the pedal effort based on the cardio level you are choosing. In the case of gear bicycle in real life, you will feel the same effort changes in pedaling on the road 

What are different gear systems like 7,21 gear, 8 or 24 gear, 9 or 27 gear, 10,11,12,13, etc?

 A gear mechanism in the drivetrain works in 2 places.

1) At the crank side where you can have 1, 2, and 3 sprockets to move the chain,

These are also called front gear

 

 

2) At the rear wheel size also called a cassette 

What is the usage of front gears in a bicycle?

The effort of pedaling depends on the sprocket where your chain is moving.

• A higher number of teeth on the front crank or chain wheel is needed for more speed, while a smaller teeth sprocket on the crank or a smaller chain wheel is needed for climbing.
• A smaller number of teeth on the rear sprocket or cassette is needed for speed, while a larger teeth sprocket or cassette is needed for inclined roads.

When we ride 1x drivetrain bikes such as 7, 8, and 9-speed bicycles, they are enough for small inclined roads but on steep roads or mountains the rear biggest sprocket is not able to provide enough support that we can climb the road, and the front gear lower chain wheel is needed. 

How to Choose the Right Gear combination for your usage?

To understand this, one needs to learn the basics of different bicycle categories as well.

Hybrid Bike - Designed for city commute, comes with thin tires. Hybrid bikes can have suspension or can be without suspension as well.

Mountain Bike / MTB - These bikes are ideally designed for off-roading and trail riding. They have front or rear suspension options with thicker tire sizes. 

Learn the Difference between a Hybrid Bike and a Mountain bike

Roadbike -  These are performance-oriented bikes, designed for long rides or speed. They are not suitable for off-roading or trail riding. They have aggressive riding positions which make them a little uncomfortable for regular city rides as well.

Now Let's come back to the point of choosing the right gear bicycle. 

• If you are choosing are Hybrid bike and your purpose is a city commute with some flyovers, a 1x Drivetrain is most suitable. Less moving or gear mechanisms reduce the service and maintenance as well. However, if you are taking a Hybrid bike on the mountain or Hilly areas, a 3X drivetrain is needed 
• If you are choosing a mountain bike and riding well in cities, 1x drivetrain is enough. For some steep flyovers in the case of Mountain bikes, a 3X drivetrain is needed. If you are riding on mountains then 3x or 1x11 and above drivetrain is needed 
• Roadbikes generally come with a 2x drivetrain with front 2 chain wheel and rear chain wheel possibility of 8,9,10,11,12,13 making them versatile for all-terrain usage

What is a cross-chain in-gear bicycle?

Cross-chaining happens when the bicycle chain is at extreme angles, for example, having the chain on the highest chain wheel of a 3x drivetrain on the front crank side and the highest sprocket of the rear cassette. Since the chain is not straight, the wear off/damage on the chain in this riding position is higher compared to other gear positions. The more diagonal the chain is, the less efficient the riding will be, resulting in more wear and tear. This can damage not only the chain but also, in the long run, other gear components where the chain is in motion, such as the chain wheel teeth or cassette teeth.