The Anatomy Of A Bicycle In Photos

A guide to bicycle anatomy for beginners (and know-it-alls!)

This hub is a photographic guide to the anatomy of a bicycle. It includes information on the locations of components and any technical names they may have.

Knowing the names of the components of your bicycle can help your greatly on any visit to your local bike shop. You'll no longer point to a piece of equipment on a bicycle and say 'I need a new one of those things'.

Bicycle anatomy is a relatively simple study and will help guide you around the devices and components that help you pedal your bicycle with focus on the elements of a bike drivechain, contact points and steering.

What components and parts make up a bicycle?

Any bike can help you understand bicycle anatomy. A time trial bike has pretty much the same components as any other bike with a few differences for aerodynamic advantage
Any bike can help you understand bicycle anatomy. A time trial bike has pretty much the same components as any other bike with a few differences for aerodynamic advantage | Source

Bicycle frame anatomy in pictures

The top tube of a bicycle frame- connects the seat tube to the head tube. Bicycle featured is an Argon 18 E-118 Time Trial Frame with Mavic Cosmic Carbone Wheelset
The top tube of a bicycle frame- connects the seat tube to the head tube. Bicycle featured is an Argon 18 E-118 Time Trial Frame with Mavic Cosmic Carbone Wheelset | Source
The seat tube seat tube helps to house the seatpost and drops to the bottom bracket area to join with the down tube. Bike featured is a Planet X Uncle John Cyclo Cross Frameset with Mavic Ksyrium Wheelse
The seat tube seat tube helps to house the seatpost and drops to the bottom bracket area to join with the down tube. Bike featured is a Planet X Uncle John Cyclo Cross Frameset with Mavic Ksyrium Wheelse | Source
The headtube of your bicycle houses the bearing races to allow the forks to turn and steer your bike. Pictured is the headtube of a Teschner TT Bike
The headtube of your bicycle houses the bearing races to allow the forks to turn and steer your bike. Pictured is the headtube of a Teschner TT Bike | Source

The Anatomy of a bicycle frame

Every bicycle has a frame. Whether it's the cutting edge Lotus Carbon bicycle that catapulted Chris Boardman to glory in the Individual Pursuit at the Barcelona Olympics or a simple shopper bike.

A bicycle frame consists of:

  • A Top tube. This connects the seat tube to the head tube
  • A Seat tube. A frame's seat tube will hold the seatpost to allow fitting of a comfortable saddle. The seat tube drops down into the bottom bracket area to connect with the downtube and chainstays. Your seat stays connect to the seat tube near it's top.
  • A Down tube. This connects the bottom bracket to the head tube
  • A Head tube - The head tube houses bearings to allow your forks to turn to steer the bicycle.
  • A bottom bracket - This holds a set of bearings to allow your cranks to turn and power your bicycle.
  • Seat stays. These connect the top of the seat tube to the rear dropout
  • Chainstays - Your chainstays connect the bottom bracket to the rear dropouts and are so called because they follow the length of your chain.
  • Dropouts - Shaped slots in the frame and fork for your wheel axles to be held into.
  • Gear Hanger- often removable and replaceable. The gear hanger allows the fitting of a rear derailler to allow the changing of cassette sprockets
  • Braze-On's- These are often O-shaped rings which allow the fitting of a set of mudguards or pannier rack.
  • Brake fittings- these fittings for a brake are specific to the type of frame. A mountain bike frame or newer style cyclocross frame will likely have a set of disk brake mounts. A road frame will have a drilled out section for fitting a road-style caliper brakeset. A traditional cyclocross frame. older mountain bike or touring type frame will have cantilever mounts for fitting.

The bottom bracket holds the crankset in place for pedalling

The bottom bracket area has to withstand alot of force as you push through the pedals so they're often a heavily built area of a bicycle
The bottom bracket area has to withstand a lot of force as you push through the pedals so they're often a heavily built area of a bicycle | Source

The seat stays and chain stays of a bicycle

The seat stays and chainstays of a bike as pictured on a Merida Time Warp Time Trial frame.
The seat stays and chainstays of a bike as pictured on a Merida Time Warp Time Trial frame. | Source

The little touches that define what a bicycle frame can be used for and the components you can fit to it.

A replaceable gear hanger (pictured on a Planet X RT 57 carbon frame)
A replaceable gear hanger (pictured on a Planet X RT 57 carbon frame) | Source
Braze on's and drilled sections of a bicycle frame allow the fitting of mudguards or panniers. Pictured frame is a Kinesis Racelight T
Braze on's and drilled sections of a bicycle frame allow the fitting of mudguards or panniers. Pictured frame is a Kinesis Racelight T | Source
Disk brake mounts on a Planet X Uncle John frame
Disk brake mounts on a Planet X Uncle John frame | Source

The anatomy of a bicycle drivechain

The drivechain of a cycle is responsible for allowing the rider to turn the rear wheel to propel themselves forward. Many involve a series of gears to allow the rider to make the going easier where required, or shift up a gear when you want to ride faster.

Parts of a bicycle drivechain

Chain- Your bicycle chain is the main link between the chainset and the cassette sprockets and forms an interface with the teeth on the chainrings and the cogs of the sprocket.

Chainset (Consisting the Crankset and Chainrings). Your chainset rotates around the bottom bracket in a clockwise motion to drive the chain forward

Cassette. The cassette is the point attached to your rear wheel which interfaces with the bicycle chain. The cassette fits to the freehub of the rear wheel. When fitted a series of pawls within the hub body lock when the cassette attempts to turn clockwise. This forces the rear wheel to rotate at the hub axle and propel the bicycle forwards

Front Derailleur- Many chainsets have a selection of different size chainrings attached to them. The front derailleur effectively 'de-rails' the chain between chainrings. This either pushes the chain upwards onto a larger chainring or drops the chain downwards onto a smaller chainring to make pedalling easier.

Rear Derailleur. The rear derailleur moves up and down the cassette in a similar manner to the front derailleur. This allows the bicycle user to make gear adjustments.

The components of a bicycle drivechain

The constituent components of a bicycle drivechain.  Bicycle pictured is a Kinesis Racelight T Winter training frameset kitted out with a mix of Shimano 105 and Ultegra components and a Mavic Aksium Wheelset
The constituent components of a bicycle drivechain. Bicycle pictured is a Kinesis Racelight T Winter training frameset kitted out with a mix of Shimano 105 and Ultegra components and a Mavic Aksium Wheelset | Source

Bicycle Anatomy- The body contact points

There are three main contact points which your body makes with a bicycle

The pedals- Your feet connect with the pedals. Whether you're using a set of clipless bicycle pedals or flat pedals. The pedals fit into spindles on the end of the cranks.

The Handlebars- Your hands connect with the handlebars which are responsible for providing a comfortable contact point to allow for steering of the bicycle. The handlebars are clamped by a stem which connects to the forks to allow steering to occur.

The Saddle- A comfortable saddle is a requirement for many cyclists due to the need to sit on the saddle for an extended period of time. The saddle attaches to a seatpost which allows the saddle height to be adjusted.

The bicycle contact points. Pedals, saddle and handlebars

The pedals form and interface between your bike and your body. Clipless pedals create a more stable connection.
The pedals form and interface between your bike and your body. Clipless pedals create a more stable connection. | Source
Your saddle is the point you sit and therefore has to be a comfortable contact point.
Your saddle is the point you sit and therefore has to be a comfortable contact point. | Source
You hands connect to the handlebars
You hands connect to the handlebars | Source

The stem is a key part of the steering system

The bicycle stem rotates around the headtube as an axis.
The bicycle stem rotates around the headtube as an axis.

Bicycle Anatomy- the steering system

When you're riding you're bicycle you really need to be able to steer it in whatever direction you need to travel.

The Steering system is made up of the following bike components

The Headset- The headset is a set of bearings which fits to the headtube of the frame to allow the forks to rotate which directs the front wheel in the direction you wish to travel.

The Forks- Your bicycle forks consist of effectively two parts- A section of tubing which is often known as the 'Steerer Tube' which connects to a point where the forks become the 'Fork Blades'. At the base of the fork blades are a set of dropouts which allow the front wheel to fit into securely.

The Stem- The bicycle stem is responsible for connecting the fork steerer with the handlebars and allows a the handlebars to rotate around the fork steerer as an axis.

The Handlebars- as mentioned above in the contact points section. The handlebars are one of the three main body contact points of a bicycle.

The Front Wheel- your front wheel is responsible for guiding the bicycle in the direction the cyclist chooses to send it.

The anatomy of the bicycle steering system

The anatomy of the steering system all rotating around the fork steerer tube as an axis to guide the bicycle where you want to go. Feature bike is a Planet X RT 57
The anatomy of the steering system all rotating around the fork steerer tube as an axis to guide the bicycle where you want to go. Feature bike is a Planet X RT 57 | Source

Integrated STI shifters feature brake levers and gear shifters

A set of integrated STI shifters feature brake levers and gear shifters
A set of integrated STI shifters feature brake levers and gear shifters | Source

The Cockpit- Braking and changing gears

The cockpit of the bicycle is responsible for it's control

The Brake Levers- The brake levers when pulled inwards draws the brake blocks or disc brake pads towards a bicycle rim or brake disc surface to allow speed to be reduced

The Gear Shifters- These are responsible for changing gears and are connected by cables to the front and rear derailleurs

The Brakeset- These are generally one of a number of types, however they allow work by having a set of pads which draw towards and connect with a surface to slow the bicycle down.

Types of bike brakesets are

Cantilever brakes- (as featured below) Cantilever style brakesets are drawn together through the use of a cable and yoke as the yoke is lifted upwards. Cantilever brakes are traditionally used for cyclocross bikes and touring bicycles.

Caliper brakes- these fix to a single point on the frame or forks directly above the tire and rotate to drawn the brake pads together and use the bicycle rim to slow the rider down

Disc Brakes- Disc brakes are some of the strongest bicycle brakes available and are mainly used on mountain bikes. A disc brake will use a metal disc which fits to the bicycle hub. This removed the need for traditional rim style bicycle brakes.

The brakes help a cyclist slow down

A cantilever rim brake as used on a touring style or older style cyclocross bike
A cantilever rim brake as used on a touring style or older style cyclocross bike | Source

Bicycle wheel anatomy

The main componant parts within the anatomy of a bicycle wheel.
The main componant parts within the anatomy of a bicycle wheel. | Source

The anatomy of a bicycle wheel

The wheels are a key component on any bicycle and allow motion to occur.

A bicycle wheel consists of the following components

Hub- the bicycle hub forms to main axis for the wheel to rotate around. A hub will contain a set of bearings to allow this to occur while also providing a point of exertion for the spokes at the hub flanges

The rear hub will also contain a pawl mechanism attached to the freehub (unless you're riding a fixed wheel bike). The pawl mechanism allows the wheel to spin when the cyclist is not pedalling, however it engages once the rider begins to pedal forwards to driver the rear wheel.

Rim- The bicycle rim is responsible for housing the tire and providing a braking surface where a rim brake is used. Generally the outer edge of the rim will be machined and potentially ceramic coated to provide assured and stable braking even in the wet.

Spokes- The spokes are responsible for connecting the rims with the hub. They generally fit into the hub flanges and then will connect with a spoke nipple at the rim which holds them in place. The spokes are responsible for keeping the bicycle wheel 'true' and uniform to rotate in a near perfect circle. The tension in each of the spokes hold the wheel true and a loss of the tension will lead to a wheel losing shape.

Tires- Tires generally come in two types. Clincher tires (Often known as HP or High Pressure) fit to a hooked bicycle rim and are held in place through the use of an inner tube. Tubular tires fix to a rim with ultra strong glue or tape and are effectively a tube with a tread (hence the name tubular tire). A relatively new invention is the tubeless clincher tire which has become popular with Mountain Bikers which involves a tight seal created between a clincher tire and a special rim. This style has slowly started to make its way into the road bike marketplace.

Disk Wheels replace spokes with a continuous carbon layer for aerodynamics

A disc wheel doesn't use spokes. A layer of carbon provides the link for an aerodynamic advantage. Pictured is a carbon disc wheel marked as a Zipp disc. I'll offer a cash prize to anyone who can tell me what disc wheel this actually is.
A disc wheel doesn't use spokes. A layer of carbon provides the link for an aerodynamic advantage. Pictured is a carbon disc wheel marked as a Zipp disc. I'll offer a cash prize to anyone who can tell me what disc wheel this actually is. | Source

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Comments 2 comments

CyclingFitness profile image

CyclingFitness 4 years ago from Nottingham UK Author

Thanks Tim- the drive chain on the kinesis needs replacing but not everyone's bike looks pristine.

You also missed that I haven't put a brake set in the mix too- that's getting added later today

Thanks for the feedback. CF


timmathisen profile image

timmathisen 4 years ago from the Land of Lincoln

Another awesome cycling hub. Anybody who reads this should never call a part on their bicycle a doo-hickey or thingamajig again. But there was one part -- the shifters -- that I didn't see mentioned. Also, the drivetrain on that Kinesis Racelight could use a serious cleaning!

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