Bike Anatomy: How Do Bikes Work?

Most people know the basics parts of the bike: wheels, seat, frame and handlebars. However, there are many more components that make up the anatomy of a modern bicycle - which vary by style. Here we’ll cover the core components that make up the diverse world of bicycles, catering to the different needs and preferences of riders everywhere. If you're curious how the parts of a bike look in specific styles, check out "Which Bike is Right for You?".

Wheel

More than just a tire, the wheel consists of the rim, spoke and hub. Depending on the style of the bike, the tire can range from thin and bald to fat and knobby. Thinner tires are better for flat, smooth surfaces like pavement. Conversely, you'll want fat knobby tires for offroad adventures. The spokes connect the rim to the hub and provide the support and shape of the wheel. The greater number of and higher the gauge (thickness) of the spokes equates to the support and rigidity of the tire. The hub is at the center of the wheel and connects the spokes to a central point and contains the axle, which provides the connection point of wheel to the bike frame/fork.

Frame

The frame can vary in shape, size and construction. It can be made from steel, aluminum, carbon fiber or magnesium composite. It provides structural integrity and houses most of the other components. It consists of the top tube, head tube which connects the fork and handlebars to the frame, down tube, seat tube, seat stay and chain stay.

Seat

Also known as the saddle. It can vary in size, shape and padding thickness and is highly customizable based on the rider’s preference.

Handlebars

Similar to the seat, the handlebars can vary in size and shape depending on the style of the bike and rider preference. The brake levers and gear shifters are, usually, attached to the handlebars.

Crankset/Chainset

This is what makes the bike move when you pedal. The pedals are attached to the crank via the crank arms, which are attached to the chainrings (front gears of the bike). The chain attaches to the chainrings in the front and the cassette on the rear tire. The cassette is the cluster of stacked gears or sprockets the rider can shift. The rear derailleur moves the chain from one sprocket to another when you shift gears. The jockey wheel keeps tension on the chain when you’re shifting gears. If a bike is a single or fixed gear, it will not have a jockey wheel.

Pedals

Like brakes, there are two main styles of pedals. Flat/platform pedals are flat and your feet freely sit on them. Clip-in pedals require special shoes that clip-in and provide better connectivity that can deliver more energy and reduce slippage.

Brakes

There are two main styles of brakes: rim and disc. Rim (also called cantilever) brakes apply pressure to the rim to slow or stop the bike. They are the most common because they are light, inexpensive and easy to maintain. Disc brakes provide better stopping ability and work better in wet conditions. They are attached to a metal disc that sits on the hub of the wheel.

This is a beginner’s guide to a bike’s components, but you can always narrow your research further if desired. Now you have a basic understanding of all those different things on your bike, or you may have a better idea of what to look for in your next one. Check out "Which Bike is Right for You?" for a deeper dive on how these components vary by bike style, or dive into some bike maitenance tips.