The Anatomy of a Bicycle

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Last updated: Oct 25, 2021 by Lesley Lang
3 min read

Introduction

The purpose of this article is to provide a basic introduction to the components that make up a bicycle. The article has been split up into multiple systems that make up an entire bike to keep things clear and easy to digest. These include: the frame, the steering and braking, the drivetrain, the wheels, and the saddle area.

The Frame

Bicycle diagram of the frame components

  • Head Tube: Houses the components needed for steering (fork, headset, etc.).

  • Top Tube: Connects the head tube and the down tube.

  • Down Tube: Connects the heat tube to the bottom bracket shell.

  • Seat Tube: Houses the seat post.

  • Seat Stays: Connects the seat tube to the rear dropouts.

  • Chain Stays: Connects the bottom bracket shell to the rear dropouts.

  • Bottom Bracket Shell: Houses the bottom bracket to allow for pedaling.

The Steering and Braking System


Road bicycle diagram of the steering and braking system [1]

  • Handlebars: Enables the rider to steer the bike.

  • Stem: Connects the handlebars to the steerer tube of the fork.

  • Fork: Holds the front wheel, the steerer tube of the fork passes through the head tube and connects to the handlebars; this allows for the front wheel to rotate with the handlebars.

  • Integrated Shifter/Brake Lever: Road bikes typically combine the shifter and brake levers into one component. The brake levers allow the rider to apply the brakes.

  • Front and Rear Rim Brakes: Reduces the speed of the bicycle to a gradual stop by clamping the brake pads onto the bike rims.

The Drivetrain


Road bicycle diagram of the drivetrain [1]

  • Integrated Shifter/Brake Lever: Road bikes typically combine the shifter and brake levers into one component. The shifters allow the rider to adjust their drivetrain gear ratios.

  • Chain: Utilizes the power provided by the crank arm to drive the wheels of the bicycle.

  • Chain Rings: Is a set of one or more sprockets attached to the crankarm.

  • Cassette: Also called the cogset, is a set of multiple sprockets attached to the hub of the rear wheel.

  • Front Derailleur: Shifts the chain to a different sprocket on the chainrings.

  • Rear Derailleur: Shifts the chain to a different sprocket on the cassette.

  • Crank Arm: Drives the bike chain by converting the pedaling motion from the rider into a rotational motion.

The Wheels

Road bicycle diagram of the wheels [1]

  • Spokes: Rods connecting the hub and rim to transfer loads caused by the weight of the rider and the bike.

  • Rims: Outer edge of the wheel holding the tire.

  • Tires: Surrounds the rims to provide traction over the surface the wheel travels.

  • Rear Dropouts: Attaches the rear wheel by hooking onto the rear axle of the bike.

  • Fork Dropouts: Attaches the front wheel by hooking onto the front axle of the bike. The fork dropouts are welded to the fork.

The Saddle Area

Road bicycle diagram of the saddle area [1]

  • Saddle: Often referred to as the seat, allows the user to sit on the bike.

  • Seat Rails: Attached underneath the saddle, connects the saddle to the seat post.

  • Seat Post: Inserted into the seat tube to support the saddle of the bike.

  • Seat Clamp: Locks the seat post into position to prevent it from rotating or sinking into the seat tube.

References 

[1] Pinterest, 2020. Endurance Race Bikes | Trek Bikes. [image] Available at: <https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.pinterest.com%2Fpin%2F66428163228384576%2F&psig=AOvVaw0hVbPyBFTFQhVewAazLXz6&ust=1606758558115000&source=images&cd=vfe&ved=0CAIQjRxqGAoTCLCRnJuoqO0CFQAAAAAdAAAAABD1AQ> [Accessed 2 December 2020].

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