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If you’re new to cycling, then bikes can seem like a bit of a mystery.
All those different parts working together to make your bike move can be confusing at first. Cranks? Stems? QR Skewers? What does it all mean?!
But, having a basic understanding of the components of your bicycle and how they function will make you a better, safer rider. It can also make choosing the right bike for you and your riding an easier task.
Search online for this kind of thing though and you’ll likely get page after page of highly detailed information on bike bits.
Handy if you’re a bike mechanic, sure, but less use if you just want to know which bits to press, and which bits to turn, so that you can get out there and start riding.
So, in this beginner’s guide, we’ll walk you through the ‘headline’ parts of a bike. These are the components that hold the bike together (the frame), make it go (the ‘drivetrain’), and make it stop (the brakes).
Later on we’ll dive deep on each of these components, arming you with expert-level knowledge. But, right now, the key is to just get you moving.
The frame is the backbone of your bike, and just like your own spine, its job is to hold all the ‘organs’ (AKA the bike components) together.
Bike frames can be made from a variety of different materials. All of which can affect the properties of the finished bike and the price.
Typical frame materials include:
Common Bike Frame Materials
|Lightweight, stiff, affordable (very common)
|Very lightweight, absorbs vibration, expensive (high-end bikes)
|Durable, reliable, heavier (making a comeback)
|Strong, lightweight, resilient, costly (high-end bikes)
“Geometry” refers to the shape of the frame including lengths of each section and the angles of joints.
Both the geometry and sizing vary between bike frames:
- Road bikes have a slimmer frame with dropped handlebars giving an aerodynamic position for faster speeds
- Mountain bikes have a more upright frame giving better control and an ability to spot obstacles on trails
- Hybrid bikes combine features of road and mountain bikes for versatile everyday riding – upright positioning with slimmed down frame tubes
When choosing a bike, always refer to the manufacturers’ measurement charts to help you pick the proper frame size for your height and dimensions. Where possible, you should also take a bike out for a test ride before you make a purchase.
Proper frame size provides comfort, efficiency, and bike control. Too big and you may not be able to control the bike, too small and you won’t be able to pedal efficiently.
As an aside, the more I cycle the more I start to ‘silently judge’ whether folk are on the correct size bike for them. If the bike is too big (and the saddle set too high) they’ll have to shift their pelvis from side to side as they ride in order to reach the pedals. Too small (with the saddle too low) and their knees will constantly be in danger of hitting their chin!
A couple bits of jargon to look out for in bike frames are “standover height” and “reach”.
Standover height is the distance from the top tube to the ground.
A small gap of 1-3 inches between your crotch and the tube, with both feet flat on the ground, allows you to comfortably mount and dismount. This is critical when you’re using your bike to carry kids or groceries, when tilting the bike to one side would be dangerous.
Reach is the horizontal measurement from the bottom bracket (where the pedal cranks meet) to the point where the handlebars attach to the bike.
It’s called “reach” because it’s an indication of how far you have to lean forward in order to reach the handlebars.
Road bikes typically have a longer reach than hybrids or mountain bikes. This puts the rider into a more bent forward position. Aerodynamic, for sure, but it can also be somewhat uncomfortable if you’re not used to it. The ideal reach is one where you are slightly leant towards the handlebars, without overstretching.
Handlebars are the most direct method of steering a bike.
They’re not the only way though.
At low speeds you’ll find that virtually all the steering is carried by turning the handlebars – turn left to go left and vice versa.
At higher speeds steering is done more by shifting your body weight and leaning into the turn – lean left to go left and right to go right.
There are many different types of handlebars available for bikes. As a general rule of thumb, the wider the handlebars, the easier it will be to change direction.
This is why mountain bikes and hybrids typically have wider handlebars (for navigating twisty trails and city streets). Whilst road bikes have narrower handlebars for faster straight line speeds.
As well as being a handy spot to put your hands, the handlebars are also where you’ll find other components that you need your hands to operate. Brakes, gear shifters, bell, and maybe a bike computer.
The bike saddle is where you park your butt when cycling.
It’s also the source of most complaints that cyclists have about their bike.
Well, their are only three points where the cyclist’s body touches the bike: the handlebars, pedals and the saddle.
Of these, most of the cyclist’s weight is on the saddle.
Unfortunately, our butts really aren’t there for sitting on and so long periods of cycling can lead to soreness in the perineal or genital areas, and skin irritation on the inner thighs.
It’s a literal PITA.
But, it doesn’t have to be that way!
There are a wide range of saddles available – different shapes, varying widths, more or less padding, even noseless and cutout designs.
There are also cycling shorts and underwear which have integrated padding to protect your butt and lycra or spandex to protect the skin on the inner thighs.
The wheels on a bike are where the rubber meets the road.
A bike or bicycle will always have two wheels (“bi” = 2). However other styles of “bike” also exist which have more wheels (such as a tricycle with three) or less wheels (such as a unicycle with one).
Bike wheels consist of a number of individual parts:
- central hub
- spokes radiating out from the hub
- wheel rim
- inner tube with valve stem
The hub sits at the center of the wheel, attached to the axle and allows the wheel to spin.
Metal spokes radiate out from the hub and connect to the rim. They might not look strong but the spokes combine together to give a huge amount of strength to the wheel.
The rim forms the outer circular edge of the wheel and holds the tire and inner tube.
The inner tube sits against the wheel rim inside the tire. It’s inflated with air and gives shape to the tire. It has a valve stem which pokes through a hole on the inside of the wheel rim – this is where a pump can be attached in order to inflate and pressurize the tube. Inner tubes come in different sizes and it’s important to pick the right one.
The tire wraps around the tube and is held firmly on the wheel rim. The tire has thicker rubber, often with a tread pattern for grip, and this helps to protect the tube from punctures.
Bike wheels come in many different sizes. That said most modern bikes use one of only four wheel sizes.
Standard wheel sizes include:
|On older mountain bikes, and many hybrids
|On newer mountain bikes
|On road bikes, fitness bikes, commuter/city bikes
|On hybrids or newer mountain bikes
For bike tires, the width and tread pattern differ depending on the wheel rim size and the intended riding conditions.
Wider tires and large knobby treads provide traction in dirt. Narrower tires with smoother treads are faster on pavement.
A pro tip is to regularly check that the tire pressure is correct before riding (this will usually be indicated on the tire sidewall).
Underinflated tires increase rolling resistance and wear. They can also lead to punctures (known as ‘snake bites’ or pinch flats). Overinflated tires can also result in punctures and, in the case of trail riding on a mountain bike, give an uncomfortably bumpy ride.
The drivetrain delivers power from your legs to the wheels through a system of interconnected parts.
- Pedals deliver the power from a rider’s legs to the crank arms. Pedals come in a number of different types, including platform, clipless, or toe-clip styles
- The crank arms deliver this power to the chainrings
- The chainrings are toothed discs that attach to the crank arms. They come in sets of single, double and triple configurations
- The chain connects the chainrings to the rear cassette transferring power to the rear hub and wheel
- A front derailleur shifts the chain between chainrings to change gears, operated by a shifter on the handlebars (note that if there’s a single chainring, there won’t be a front derailleur as it’s not needed)
- In the rear, a cassette or freewheel contains sprockets of varying sizes. There may be between one and nine sprockets
- The rear derailleur shifts the chain up and down the cassette, from sprocket to sprocket. This is also operated by a shifter on the handlebars
All these components work together to turn the rotating motion of your legs into forward motion of the bike.
Truth is you won’t be able to see that many gears, no matter how closely you look.
The way that these numbers are arrived at is by multiplying the number of chainrings by the number of rear sprockets.
As an example, let’s say your bike has three chainrings up front and seven sprockets at the back. Then your bike will have 21 gears (i.e. 3 x 7 = 21).
Before setting off on a bike, it’s a sensible idea to know how you’re going to stop.
That’s where brakes come in.
Brakes allow you to control your speed and allow safe stopping.
There are different types of brakes available depending on the style and age of a bike. All of these operate with the same principle, which is to press a brake pad against the moving wheel.
Rim brakes squeeze brake pads against the wheel rim.
Disc brakes have pads that squeeze a rotor attached to the wheel hub. Many modern bikes now have disc brakes as these will typically provide more reliable performance in wet or muddy conditions.
Brake controls mounted on the handlebars activate calipers or pistons to engage the pads. Pulling a lever squeezes the pads against the rim or rotor. The harder you squeeze the lever the more force is applied.
If your brakes aren’t working then it’s very difficult to stop your bike. For that reason it’s super important to make sure that your bike brakes are properly maintained and functioning correctly before every bike ride.