Parts Of A Bicycle Explained: Comprehensive Guide To Your Bike

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Discovering a love for cycling but struggling to get to grips with the jargon?

Or do you want to explain what’s wrong with your bike to a mechanic, but don’t know what the broken part of the bike is called?

Fear not – we’re here to help!

In this article, we’ll get you familiar with all the key parts of a bicycle. Whether you’re a beginner rider or you’ve been cycling for decades, you’ll know your cassette from your crank arm in no time!

Don’t worry if you feel daunted by the task of learning all the different parts of a bike – to keep it simple, we’ve broken them down into five easy groups (with pictures):

Ready to get clued up on your bike parts’ names?

Let’s get started!

#1: The Frame

Annotated diagram showing the parts of a bike frame.

The frame is the main structural body of your bike, to which the other parts of a bicycle are attached.

Bicycle frames are usually made of aluminum, titanium, or steel, though high-end racing bike frames sometimes use carbon fiber.

  • Top Tube – the tube which runs across the top of the frame.
  • Down Tube – the tube which descends from the front of the bike towards the pedals.
  • Seat Tube – rises from the bottom of the down tube towards the saddle.
  • Head Tube – The short section running between the top tube and the down tube.
  • ‘Triangle’ – the empty space formed in the middle of the four tubes.
  • Chainstay – extends backward from the point where the down tube meets the seat tube.
  • Seatstay – drops from the rear end of the top tube to meet the back of the chainstay.
  • Bottom Bracket Shell – the gap where the seat tube, down tube, and chainstays meet, into which the bottom bracket is installed. The bottom bracket is the set of bearings that act as the interface between the frame and the crank arms.
  • Rear Dropouts – the reinforced part of the frame that the rear wheel slots into. Fixed-gear track bikes use horizontal dropouts (also called “track ends”), whereas most bikes with gears use vertical dropouts.

Strictly speaking, the saddle, the seat post, and the fork are not part of the frame – but we’ve included them here to help keep things simple.

  • Fork – the double-ended section which the front wheel attaches to.
  • Saddle – the bike’s seat.
  • Seat Post – extends upwards from the seat tube to hold the saddle.

The frame and front fork together are referred to as the frameset.

#2: The Wheel

Annotated diagram showing the parts of a bike wheel.

The humble bike wheel may seem simple, but it has a combination of key components that work in tandem to keep you rolling!

  • Wheel Rim – the circular metal band of the wheel to which the tire and inner tube are fitted.
  • Tire – the outer layer of rubber which touches the ground. The three main types of bike tire systems are clinchers (which use inner tubes), tubeless (common on MTBs and increasingly used for road bikes too), and tubular tires.
  • Inner Tube (Clincher Tires Only) – the inflatable rubber tube housed between the tire and rim.
  • Valve – pokes through a hole in the rim and is used to inflate the inner tube. Most valves are either the long, thin Presta valves (more modern) or the wider Schrader valves (common on older bikes).
  • Spokes – thin rods connecting the rim to the wheel’s hub.
  • Hub – the central part of the wheel, containing ball bearings that allow the wheel to spin.
  • Freehub (Rear Wheel Only) – the component in a modern bicycle’s rear wheel hub that allows the wheel to spin freely when coasting, but engages the drivetrain when pedaling. The cassette slots onto the freehub body.
  • Fastening – there are several methods of fastening the wheel to the frame, the most common of which is the quick-release skewer. Other fastenings include thru axles and hexagonal axle bolts.

#3: The Drivetrain

Annotated diagram showing the parts of a bike's drivetrain.

The drivetrain refers to all the parts of a bicycle which are used to drive it forward. The three main brands for bike drivetrain components are Shimano, SRAM, and Campagnolo.

  • Bike Chain – transfers energy from the turning pedals to the rear wheel, propelling the bike forward.
  • Pedals – provide a contact surface for your legs to rotate the chainset. They can either be flat pedals or clipless pedals (which are pedals you clip into, despite the name).
  • Crank Arms – the arms that connect the pedals to the chainset.
  • Chainrings – the front set of gears. The larger the chainring, the harder it is to pedal, and the further each rotation will push you forward.
  • Chainset – the name given to the crank arms and the chainrings as a unit. Sometimes referred to as the “crankset“.
  • Cassette – the rear set of gears. Usually contains anywhere between 5 and 12 sprockets to allow for a wide range of gear ratios.
  • Front Derailleur – the component that shifts the chain between the front set of gears on the chainset.
  • Rear Derailleur – the component that shifts the chain between the cogs of the cassette to change gears at the rear. They include a spring and jockey wheel to maintain tension in the chain regardless of the gear combination you ride in.
  • Derailleur Arm – the arm which extends from the rear derailleur, with pulleys to feed the chain through. The derailleur arm is spring-loaded to remove slack from the chain when using smaller gears.
  • Derailleur Hanger – the metal piece connecting the rear derailleur to the frame. Also known as “frame-savers”, they’re intentionally designed to bend under pressure as a failsafe to prevent damage to the frame or derailleur, which would be far more expensive.

#4: The Handlebars (And Steering Components)

Annotated diagram showing the parts of a bike's handlebars and steering components.

As well as providing steering control, a bike’s handlebars are (usually) home to the rider’s controls for the brakes and gears.

Handlebars come in many different forms. The type shown here are drop handlebars, commonly found on road bikes as they allow for a more aerodynamic rider position, whereas flat bars will usually be found on mountain bikes.

Other forms include the butterfly handlebars often preferred on touring bikes for their comfort, or the bullhorn bars sometimes seen on retro track bikes.

  • Brake and Gear Levers – the position of the brake levers depends on the style of the handlebar. On drop handlebars, the brake and gear controls are sometimes combined into a single pair of levers which are squeezed to apply the brakes or pushed to the side to change gear. Flat bars are more likely to use trigger or twist shifters.
  • Brake Hoods – protective covers for the brake levers on drop handlebars, which are normally ergonomically designed to be a comfortable handhold while riding.
  • Stem – connects the handlebars to the steerer tube (which extends from the top of the fork).
  • Headset – the name for the collection of parts that allow the fork and steerer tube to rotate within the head tube, acting as the point of contact between them. Typically consists of a pair of cups containing ball bearings, placed at either end of the head tube.

There are two main designs for stems: quill stems (which are ‘L’-shaped and drop directly into the headset) and threadless stems (which clamp directly around an extended fork steerer tube protruding above the headset).


Quill stems are largely obsolete on modern bikes.

Integrated handlebar and stem units are becoming increasingly common on high-end aerodynamic road bikes, but restrict adjustability and make maintenance far more complicated.

#5: The Brakes

Annotated diagram showing the parts of a bike's brakes, including both rim brakes and disc brakes.

There are two main types of bicycle brakes: rim brakes and disc brakes.

Rim Brakes

Rim brakes are more common on older road bikes and are generally cheaper and easier to maintain.

It’s also easier to quickly change a wheel with rim brakes, which – along with their lighter weight – is partly why they’ve historically been preferred by professional road-racing teams.

There are many different styles of rim brakes. The type shown on the left above are called dual-pivot side-pull caliper brakes (yes, we know that’s a bit of a mouthful), which are the most common variety used on modern road bikes.

Rim brake components typically include:

  • Brake Pads – made from a durable material, they’re pressed against the rim to create friction to slow the bike down.
  • Shoes – the part that holds the brake pad.
  • Caliper Arms – the moving parts that press the brake pads into the rim. In this style of rim brake, the two caliper arms meet at a pair of pivots centered above the wheel.

Disc Brakes

Disc brakes typically outperform rim brakes in most regards.

They’re almost always used on mountain bikes but are increasingly popular on high-end road bikes as well. Most racing bikes in the professional peloton now use disc brakes.

Disc brakes can either be mechanical, using conventional wire brake cables, or hydraulic, using fluid lines to connect the brakes to the brake levers. Hydraulic disc brakes tend to deliver better performance, but are more expensive.

Disc brake components include:

  • Rotor – the metal ‘disc’ attached to the wheel hub, which gives these brakes their name.
  • Calipers – fitted on either side of the rotor, they squeeze together around it when the brake lever is pulled to create friction, slowing the bike down.
  • Brake pads.

Parts of a Bicycle: Lingo Learned!

Annotated diagram showing all the main parts of a bike.

Now you’re familiar with all the parts of a bicycle, it’s time to get back in the saddle – or the workshop – to put your new knowledge to use!

Learning how all the components of your bike work is a great skill for any cyclist. This knowledge can help you understand and identify when, where, and why there’s a problem with one of your bike parts or with your overall setup.

Getting to grips with all the different bike parts’ names can take a little while for beginners – but you can always refer back to our diagrams to check in the meantime!

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As a UESCA-certified cycling coach, Rory loves cycling in all its forms, but is a road cyclist at heart. He clocked early on that he had much more of a talent for coaching and writing about bikes than he ever did racing them. In recent years, the focus of Rory's love affair with cycling has shifted to bikepacking - a discipline he found well-suited to his "enthusiasm-over-talent" approach.

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