Everyone knows what a bicycle is, but what about the components of one?
While the subject of bike anatomy may not seem like an exciting topic at first, the truth is that having a firm grasp of a bike’s parts and how they work gives you a better understanding of cycling, period.
When you know your bike’s anatomy, it equips you with the proper knowledge required to know when something is malfunctioning, or if it needs to be adjusted and/or replaced.
Depending on your familiarity with a certain component, you may even be able to make your own repairs when needed.
We’ll save the repair guides for another day, however.
core bike components
For now, use this guide to familiarize yourself with all of the core bike components, what they do, and why they are needed. This isn’t an exhaustive guide by any means, but does go over all of the core components and aspects of a bike.
Frame
The frame is the main part of the bike, from which everything else is mounted on. It consists of the top, seat, head, and down tubes, a bottom bracket, dropouts, and a chain stay. Road bikes and mountain bikes each have very different frames, which we’ll touch on further below.
Fork
The fork is the part that holds the front wheel. It is connected to the head tube, which comes out on top of the opening, and is then connected to the stem and handlebars.
The fork is part of the steering setup for your bike, and also plays a role in shock absorption in many instances.
Forks are often made from the same material as the frame, although there are exceptions, especially in road bikes.
Saddle/Seat Post
The saddle is a another name for the bike’s seat. Saddles come in many different forms, and are dependent on the type of bike. The seat post is what hold the saddle in place, and fits into an opening on the top tube of the bike’s frame.
Handlebars
A bike’s handlebars serve a number of purposes. They are used to steer first and foremost, but also house your brakes and gear shifters.
Depending on the bike, handlebars can take on different shapes, and may have different grips as well.
Stem
One of the more overlooked bike components, the stem is what connects your handlebars to the bike’s fork.
Stems come in many different lengths and angles, all of which provides different feels for how your bike is steered.
Brake System
Rather than just single out each brake component in its own section, we’ll discuss each part that goes into making the brakes function.
Calipers are the assembly that holds each brake pad, and are positioned directly over the tops of the bike’s wheels. There is a brake pad on each side, and when the brake lever is squeezed, it causes the pads to close on each side of the tire’s rim, resulting in stopping.
Some bicycles use a disc brake system instead. In this instance, there are small metal discs located in the center of each wheel, where a special mechanism is positioned to grasp the disc, which in turn stops the wheels from spinning.
Cassette
These are your high gears, located on the back wheel. The cassette refers to the group of cogs that are together, each of which is its own gear.
Crankset
This refers to the entire assembly that’s connected to a bike’s pedals. The crank is the actual cogs, or chainring. These are your low gears, and most bikes have either two or three cranks, depending on the total amount of gears.
Derailleur
A derailleur is a mechanical “arm” that moves the chain when you are shifting gears. There’s actually two derailleurs on a bike when it has multiple gears.
The front derailleur is right by the crankset, which is located at the bottom of the frame’s bottom tube. The rear derailleur is located in the back of the frame, right at the tip of the rear triangle.
Whenever you shift a gear, the corresponding derailleur will move the chain up or down a level, depending on the shift.
Shifters
Located within reach of where your hands are places on the handlebar, the shifters are mechanisms that allow you to toggle your gear selections back and forth. Each shifter controls a different derailleur. Shifters are usually trigger-style, but some are integrated into the bike’s brake levers.
Road Bike Anatomy vs. Mountain Bike Anatomy
Road bikes and mountain bikes differ in more than a few ways when it comes to their build and components. Here are the main examples.
Fork
Mountain bikes are designed to absorb a high amount of shock, while road bikes aren’t.
Most mountain bikes have a front suspension fork with hydraulic shocks that allow the fork to compress when it needs to, absorbing the blow from a landing, or when traveling across rough terrain.
Frame
Mountain bike frames are generally thicker, and have a more relaxed profile that allows the rider to remain more upright. They may also include a rear-suspension system for added shock absorption.
Road bike frames are skinnier, lighter, and encourage a forward-leaning position.
Handlebars
Road bikes almost always have what’s known as “drop down” handlebars, which curve on the ends and angle downwards, allowing the rider to lean forward while steering.
Mountain bike handlebars are flat across, and may also have “bull horns” attached on the ends that allow a rider to sit straight up when casually riding on normal surfaces.
Saddle
The saddle of a road bike is often on the harder side, and is usually quite small.
Mountain bike saddles are generally wider, and will feature some extra padding to help absorb bumps.
Conclusion
Hopefully by now you should have a better understanding of the most important aspects of a bike’s anatomy. While we didn’t touch on everything, this guide should give you some entry-level knowledge that will come in handy down the line.
Be sure to check out our other resource articles for more information on everything you need to know about biking, as well as some helpful information on some of our favorite bikes on the market. Happy riding!
