How Does Bicycle Gearing Work?

Bicycle gears are a remarkable innovation that has revolutionized cycling. They allow us to pedal easier on uphills, maintain our ideal cadence regardless of the gradient, and sprint as fast as we can. But how exactly do they work? Read our comprehensive guide and learn everything you need to know about bicycle gearing and the art of gear shifting.

Bicycle Gears – What Are They?

Before we delve into the specifics of shifting, let’s first familiarize ourselves with the components that make up bicycle gears. 

Front Gears

In the main part of the drivetrain, where the cranks and pedal arms attach, we find the front gears, also known as chainrings. Bicycles can have one, two, or three of them. The size of the chainring affects the ease of pedaling – to put it simply, the bigger the chainring, the harder it is to pedal, while the smaller the chainring, the easier it is. In a triple-front ring setup, the smallest chainring is often called the “granny gear.”

Rear Gears

Situated at the hub of the rear wheel, the rear gears, individually referred to as cogs or sprockets, make up the cassette when assembled together. The size of the rear gear is the opposite of the front chainring – a larger rear gear makes pedaling easier, while a smaller one makes it harder.

Bike Gear Ratio

The gear ratio is the combination of the front and rear gear choice and is usually expressed in “front x rear” terms. For example, a gear ratio of “46×17” means the chain is on the 46-tooth chainring in the front and the 17-tooth cog in the rear. The gear ratio, in conjunction with the circumference of the bike’s wheel and tire, determines how far the bike will travel with one revolution of the cranks.

Top and Bottom Gears

The top gear refers to the hardest possible gear combination or the biggest front chainring combined with the smallest rear cog. For example, a gear combination of 53×11 is considered the top gear. On the other hand, the bottom gear, like 39×28, refers to the easiest possible gear combination or the smallest front chainring combined with the biggest rear cog.

Derailleurs

Derailleurs are mechanisms located above the front chainrings and below the rear cassette. They facilitate the movement of the chain from one chainring or cog to another based on input from the shifters.

Shifters

The shifters, typically located on the left and right sides of the handlebars, control the front and rear derailleurs. The left-hand shifter is responsible for shifting the front derailleur, while the right-hand shifter controls the rear derailleur. Shifters can come in various forms, including buttons, levers, or triggers, depending on the type of bike.

How to Shift Gears on a Bike?

Shifting gears may seem daunting at first, but with practice, it becomes second nature. Here’s a step-by-step guide on how to shift gears on a bike:

• Assess your current gear – Start by identifying the gear you are currently in. This will help you determine whether you need to shift to a harder or easier gear.

• Anticipate the terrain – Look ahead and anticipate any upcoming changes in terrain. If you see a hill approaching, you’ll likely need to shift to an easier gear to maintain a comfortable cadence. On the other hand, if you spot a downhill stretch, you might want to shift to a harder gear to maximize speed.

• Prepare for shifting – Before shifting, ease off the pressure on the pedals slightly to reduce the load on the drivetrain. This will facilitate smoother gear changes.

• Shift the rear gears -If you need to shift to an easier gear, use the right-hand shifter to shift to a larger rear cog. Conversely, if you need to shift to a harder gear, shift to a smaller rear cog.

• Shift the front gears – If necessary, use the left-hand shifter to change the front chainring. Shifting to a larger chainring will make pedaling harder, while shifting to a smaller chainring will make it easier.

• Maintain a comfortable cadence – After shifting, resume pedaling and adjust your cadence to match the new gear. Aim for a cadence range of 80-90 RPM, although individual preferences may vary.

• Fine-tune as needed – As you ride, you may find the need to make further adjustments to the gears based on the terrain and your comfort level. Continuously monitor your cadence and make small shifts accordingly.

Common Shifting Problems

While modern bike gearing systems are highly reliable, occasional issues may arise. Let’s explore two common shifting problems and their solutions:

Cross-chaining

Cross-chaining occurs when the chain is positioned across the front and rear chainrings in extreme gear combinations. For example, a little ring to little ring or a big ring to big ring configuration. Cross-chaining causes the chain to rub against the front or rear derailleur, resulting in noise, component wear, and reduced efficiency.

What to do: To avoid cross-chaining, it is recommended to use only a portion of the rear cassette when using the little or big ring upfront. For instance, when in the big ring, use only the bottom/smaller two-thirds of the rear cassette. When using the little ring, use only the upper/bigger two-thirds of the rear cassette. By following this practice and ensuring proper adjustment of the front derailleur, you can minimize cross-chaining and prolong the lifespan of your drivetrain.

Dropped Chain

A dropped chain occurs when the chain falls off one of the chainrings, typically in the front. This issue is often caused by misalignment or poor adjustment of the derailleur. When a chain drops, pedaling becomes impossible, and attempting to put the chain back on while still riding can lead to further complications and potential damage.

What to do: If your chain drops, it is important to stop and assess the situation. Take a moment to determine the exact position of the chain. If it is between the inner chainring and the bike’s frame, be cautious when removing it to avoid damaging the frame. If the chain falls off the outside chainring, make sure it is properly positioned around the crank before reattaching it.

To facilitate the reinstallation of a dropped chain, pull the bottom of the rear derailleur forward to create more slack in the chain. This will make it easier to maneuver the chain back onto the chainrings. It may be helpful to wear gloves or use an energy bar wrapper to handle the chain, especially if you are far from home.

Shifting Tips for Beginners

If you’re new to cycling and gear shifting, these tips will help you navigate the learning curve and become more comfortable with changing gears:

Choose the Right Gear

Before you even start shifting gears, it’s important to consider the type of riding you’ll be doing and the terrain you’ll encounter. If you’re a beginner cyclist, a bike with a triple front chainring is recommended. The wider range of gears provided by a triple chainring setup will give you easier options for tackling steep hills. If you anticipate tackling significant climbs, you may also consider a compact front chainring, such as a 50×34 configuration, which is specifically designed for climbing.

Focus on Cadence

Cadence, or the rate at which you pedal, plays a crucial role in your cycling efficiency. Most riders aim for a cadence of 80-90 RPM while sitting, with a slightly lower cadence of 60-70 RPM when standing. If you don’t have a power meter or cadence sensor on your bike, you can estimate your cadence by counting the number of pedal strokes you take in 10 seconds and multiplying by six.

Anticipate Shifts

As you gain experience, you’ll develop a sense of when to shift gears based on the terrain ahead. Anticipating shifts and making them proactively will help you maintain a consistent cadence and avoid being caught off guard by sudden changes in gradient. For example, if you see a hill approaching, shift to an easier gear before you start climbing. Similarly, if you anticipate a downhill stretch, shift to a harder gear to maximize your speed.

Practice Shifting Techniques

Shifting quickly and accurately is a skill that can be honed with practice. Familiarize yourself with your bike’s shifters and experiment with different shifting techniques. Some shifters allow for multiple clicks or rapid shifts, enabling you to change gears swiftly. Practice shifting on flat roads or in a controlled environment to become more comfortable and proficient with gear changes.

Fine-tune Your Gearing

Every cyclist has their own preferences when it comes to gear selection. Experiment with different gear combinations and fine-tune your gearing to suit your riding style and the specific demands of your routes. Pay attention to how different gears feel and assess their effectiveness in various situations. With time and experience, you’ll develop a personalized gear setup that maximizes your performance and comfort.

The Bottom Line

While bicycle gear shifting may seem like a tricky task, understanding how to use gears is crucial to simply make cycling easier and more enjoyable. Mastering the art of bicycle gear shifting can elevate your riding experience and improve your overall efficiency as a cyclist. So, what are you waiting for? It’s time to hop on a bike and put this precious knowledge about bike gears to a good use. Have a great trip!