Cyclist, Know Thy Bicycle: Parts of Your Bike

You can ride a bike without knowing you’re sitting on a saddle and not a seat, but if your tire gets a snakebite flat or your spoke needs an adjustment, will you know which parts need attention and how to talk shop decently enough to get what you need to get back on the road?

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After reading this glossary of bike parts, the answer is yes, yes you will. Worst case, you’ll know enough not to embarrass yourself.

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Essential Bicycle Parts (Most Bikes)


Let us start at the bottom with something obvious. The pedal is the piece you already know: it is here that a cyclist places their feet. The pedal is attached to the crank arm. The crank arm is rotated by the cyclist as they pedal, thus spinning the chain around the chain ring, and from whence the power of movement begins.

Chain ring

A chain ring is the round, spiky wheel connected to your cranks. It is wrapped by a chain, which it pulls around Chain rings are literally the necessary cog in the machine that is your bike. They’re the part responsible for transmitting the energy you create by turning the rear wheel via the chain.

Front derailleur

The front derailleur is the mechanism that changes the front gears by lifting the chain from one chain wheel to another (if your bike has more than one chain ring; it allows the cyclist to adapt to road conditions. How a front derailleur works.

Chain (or drivechain)

The chain consists of a set of metal links meshing with the sprockets on the chain wheel and gear wheel to transmit the pedaling motion to the rear wheel. Simple.

The drivechain on a bike consists of all the mechanics that push (or pull) the bike along: pedals, cranks, chain rings, chain, cogs (cassette) and derailleur.

The crankset (in the US) or chainset (in the UK), is the component of a bicycle drivetrain that converts the reciprocating motion of the rider’s legs into rotational motion used to drive the chain or belt, which in turn drives the rear wheel. [source]

Chain stay

The chain stay is the tube that connects the pedal and crank to the rear-wheel hub.

Rear derailleur

The rear derailleur is the rear gear-changing mechanism on bikes with multiple speeds. It acts by lifting the chain from one gear wheel to another, and allows the cyclist to adapt to changing verticals and road conditions.

Rear brake

The rear brake is usually situated near or on the right handlebar. The rear brake is the mechanism activated by a brake cable, comprising a caliper and return springs; it forces a pair of brake pads against the wheel sidewalls to stop the bicycle via friction.

Seat tube

The seat tube is the part of the bicycle frame that leans slightly to the rear. Inserted within it is the seat post, and below at the opposite end, the seat tube joins the pedal mechanism.

Seat stay

The seat stay is the diagonal tube connecting the top of the seat tube with the rear-wheel hub.

Seat post

Component supporting and attaching the seat, inserted to variable depth into the seat tube to adjust the seat’s height.


It seems counter-intuitive since the seat post supports this piece, but the saying goes “sit on a seat, straddle a saddle,” so the saddle is the small triangular spot attached to the bicycle’s frame upon which a cyclist sits their seat. Clear as mud.


The crossbar, aka the top tube, is the horizontal part of the frame connecting the head tube with the seat tube, stabilizing the frame.

Down tube

The down tube is the part of the bicycle frame connecting the head tube to the bottom bracket where the crank attaches to the frame. The down tube is the longest and thickest tube in the frame and gives it its rigidity.

Bottom bracket

The bottom bracket on a bicycle connects the crankset (aka chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and cranks to rotate. The chain rings and pedals attach to the crank arms (sometimes just called cranks).

Tire valve

The tire valve: each wheel has a small pneumatic tire valve sealing the inflation opening of the inner tube; it allows air to enter but prevents it from escaping. Usually a shrader valve on a mountain bike, and presta valve on a road bike.


A spoke is a thin metal spindle connecting the hub to the rim. Each bicycle wheel has many spokes arranged across its length, giving the wheel its strength and shape.

Tire or tyre

The tire is the part of the bike that touches the road. The tire is usually made of cotton and steel fibers coated with rubber, mounted on the rim to form the casing for the inner tube, the part inflated with air (unless the tire is tubeless).


The rim is the metal circle constituting the wheel’s circumference and on which the tire is mounted. The brake pads grip the rim’s sidewalls when brake levers are engaged.


The front hub is the middle of the wheel from which the spokes radiate outward to the rim. Ball bearings within the hub enable it to rotate around its axle. The fork attaches at the front hub, and the rear stay attaches to the rear hub.


The fork is the two tubes connected to the head tube and attached to each end of the front-wheel hub. The fork’s offset influence’s the bike’s handling characteristics.

Front brake

The front brake mechanism is engaged by pulling a brake cable, which forces a pair of brake pads to grip the rim sidewalls to slow down the front wheel.

Brake lever

The brake lever is attached to the handlebars. The cyclist activates (squeezes) the brake caliper at the handlebars and the brakes activate at the rim sidewall via a brake cable.

Head tube

The head tube attaches the stem to the fork and down tubes and uses ball bearings to transmit the steering movement to the fork.


The stem of a bike is adjustable, a cyclist can raise or lower the stem height depending on the reach of the rider and desired riding positioning. The stem is inserted into the head tube and supports the handlebars.


The handlebars attach to the bike stem, and are the way by which a cyclist steers and brakes the bicycle.

Brake cable

The brake cable is an entwined, covered steel cable running along the length of the top tube or down tube depending on the bike style, and transmits the pressure exerted on the brake lever to the brake when the cyclist squeezes the brake lever.


The shifter is the lever for changing gears via tension on a cable that moves the derailleur and ultimately, the chain.

Here is a handy, more detailed diagram illustrating the parts of a road bike or mountain bike from RideOn Down Under.

Optional Bicycle Parts

toe clip

Toe clip: This is a metal/plastic/leather device attached to the pedals that covers the front of the feet, keeping the feet in the proper position and increasing peddling power.

Reflector: Device returning light toward its source so that other users of the road might see the cyclist.

Fender: Piece of curved metal covering part of the wheel to protect the cyclist from being splashed by water.

Panniers: A bicycle pannier is a basket, bag, box, or similar container, carried in pairs, attached to the sides of a bicycle or motorcycle.

Rear light: A red light, solid or flashing, that makes the cyclist visible in the dark from behind.

Front Rack: Rack on the front of the bike. Lowrider racks are touring bikes as they keep your pannier weight as low as possible to the ground; this allows heavily-laden touring bikes to feel as stable as possible at low to medium speeds. Porteur racks are designed to stabilise large front loads above the wheel. Randonneur front racks are used to support the weight of small randonneur bags.

Carrier (aka Rear Rack): Device attached to the back of the bicycle for carrying bags (panniers) on either side, and securing packages on top.

Tire pump: Device that compresses air and is used to inflate a bicycle tire’s inner tube. Usually has both a presta and schrader valve.

Water bottle clip: Metal or Plastic support attached to the down tube or the seat tube for carrying the water bottle.

Headlight: Lamp attached at the front of the bike, illuminating the ground a few yards in front of the bicycle. Usually white light, flashing or solid.


Know Your Bike: Rake and Trail

First: “what the fork is a bike’s rake and trail?!” you might be asking.

“Rake” refers to the angle between the bicycle’s front forks and the ground, and is also known as its offset.

“Trail” is the distance between the pivot axis of the fork and the centre of the contact patch of the front tire at the ground. We will go into more detail below about how to measure this, just know that trail is one of the most important determiners of your bike’s handling characteristics.

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How to Measure the Rake of a Bike Fork

Measuring the rake of a fork takes a little mental gymnastics – here is the easiest way to figure it out:

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  • First, draw an imaginary line that follows the steer tube of the fork.
  • Next, following the same angle as the first line, draw a line through the middle of the drop-outs of the fork – the slots where the front wheel’s axle sits. The distance between the two lines (measured along a third line which runs perpendicular to both) is the rake of the fork.

By itself, rake means nothing. When installed on a bike, a fork’s rake will alter the bike’s trail – which is again easier to measure than to explain.

Next, Measure Your Bike’s Trail

the pink on the ground is the bike's measured trail
the pink is the measured trail

Having installed your fork on your bike, and added wheels, tire, etc., follow the first imaginary line above (which will be following both the fork’s steer tube and the frame’s head tube) to the ground. Now, draw a vertical line from the middle of the fork’s dropouts to the ground – which is where the front wheel touches the ground. Measure the distance between the two points on the ground and you have the bike’s trail – the distance by which the front wheel can be said to “trail” behind the bike (or at the least the bike’s fork’s theoretical point of contact with the ground). The rake of a bicycle’s fork is one factor in determining its trail, with the others being the angle of the frame’s head tube and the size of the wheel (including tire).

Why Care About a Bike’s Trail?

All other things being equal, the less rake the fork has, the greater the bike’s trail – and vice versa.

As a measurement, a bike’s trail is an important determiner of how it will handle. The greater a bicycle’s trail number, the more stable its handling.

Inversely, the lower the bicycle’s trail number is, the more maneuverable or “twitchy” – that is, the easier to overcome its tendency to go in a straight line – it will be.

So why didn’t the sales guy at the shop where you bought your bike tell you about trail? If it affects the way your bike handles, you’d think it would be something that you want to know about, if not choose, right?

Well, the fact is that most bikes have a pretty standardized amount of trail.

For a given type of bicycle, you want a particular kind of handling.

A bike with lots of trail will be directionally stable: it will tend to go straight and be easy to ride hands-off even when the road is a little uneven. Such a bike will take more physical effort to steer than a bike with less trail.

For example, touring bikes should be pretty stable, while a racing bike should be more maneuverable.

If someone tried to design a twitchy touring bike or a racer that handled like a truck, they’d quickly be out of a job.

How Does Fork Rake Affect Handling?

But if you did want to change the handling characteristics of a given bicycle, one (and probably the easiest) way to do it would be change to a fork with a different rake.

Just remember, trail and rake have an inverse relationship.

High Rake = Less Trail = Less Stability but More Responsive Handling

Road bikes and bikes with narrower handlebars are built for better handling.

If you changed the curved fork on your road bike to a straight one that followed the same, steep line as the frame’s head tube, your bike would actually become more stable, and less responsive.

Low Rake = More Trail = More Stability

On the other hand, should you select the fork with the least amount of rake, you’re effectively building a “randonneur” — a bicycle that’s meant to be ridden at speed over long distances. For such an application, you’d want something stable, and a low-rake fork provides lots of trail. Cruisers and touring bikes are examples of bicycle styles with more trail.

A mid-rake fork will perform reasonably well for both stability and responsiveness. . . but where’s the fun in that?