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Bike components explained

PARTS OF A BIKE EXPLAINED 

Do you know your groupset from you gearset and your chainrings from your cassette? Here are the most important parts of a bike explained. 


Sure, we can all point the the saddle and the handlebars, but, if you're just starting out in cycling, components such as the chainrings and cassette can be a little harder to identify. Well fear not, here's our guide to the most important parts of a bike.

Frame

The bike frame forms the main structure of a bike. From road bikes to commuter bikes, mountain bikes and cyclocross bikes, frames come in lots of different shapes and sizes to suit different styles of riding. Getting a good quality frame is a good starting point when buying a bike as many of the other parts and components can be adapted, upgraded and replaced over time without changing the frame itself. Make sure the frame gives you the best riding position for its intended use and get the right size for ultimate comfort and performance.

Groupset

A groupset is at the very heart of the bike and is made up of the brake and gear shifters, front and rear derailleurs, front and rear brakes, chainset, chain and rear cassette. 

Brakes

Bike brakes allow you to control your speed whilst cycling and also bring the bike to a complete halt, so making sure you have high quality working brakes is vital for your safety. Additionally, brakes can also aid performance on the bike; on the road you can vary your speed according to other cyclists and vehicles around you and if you’re on the trails you’ll need to modulate your braking to control the bike on tricky descents. There are four types of brakes; V-Brake, Cantilever, Calliper and Disk brakes. V-Brakes and Cantilever brakes are commonly used on commuter, trail and entry level mountain bikes. Calliper Brakes are popular on road bikes. Disk brakes are most often used on Mountain Bikes but are now starting to appear on Road Bikes too. 

Chainset

The chainset of your bike includes the cranks, bottom bracket and chainring. These components are fundamental to the drive chain which is essentially the engine, driving the bike forward. There are many different options when it comes to chainsets but the key to performance is to find a set up that suits your riding activities best. 

Bike parts explained: The chainset

CHAINRINGS

Road bike chainrings include compact (good for sportive style riding), standard (high gears for hill climbing) and triple chainrings (good range and low gears, good for touring bikes). For MTB you can choose between triple (good for hill climbing), double (good range of gears for both climbing and descending) and single chainrings (simplified setup becoming more popular with 11 speed cassette). 

CRANK ARMS

Cranks Arms are turned by placing force on the pedals and they then rotate the front chainrings. Standard crank arms on older bikes are usually made of steel so an upgrade to aluminium or carbon can make good weight savings. You can also buy different sizes to suit your leg length too. 

BOTTOM BRACKET

The bottom bracket is an axle with bearings which connects the crank arms and allows them to turn freely. Some riders choose to upgrade from the old cartridge style bracket to a new external bottom bracket which tends to be a bit lighter and stiffer. 

Derailleurs

Derailleurs are the mechanical system that helps you to change gear on the bike. The mechanism carefully moves the chain from one chainring to the next. On the rear cassette the derailleur will control gears up and down the sprockets and if you have more than one chainring on the front, you’ll need a derailleur to move the chain between these as well. Derailleurs have traditionally been operated using cables but more recently electronic derailleurs with motorised movement have become available too. 

Rear Cassette

The rear cassette determines the range of gears that you have on the bike. Made up of several sprockets of varying sizes, each cog will require a different level of pedal power with the larger sprockets providing easier gears and the smaller sprockets providing harder gears. Finding the optimum number and size of sprockets for your rear cassette can significantly improve your riding experience. The difference in size between the sprockets will also affect the jump between each of the gears so you need to decide how fine you want the changes to be. 

Wheelset

A wheelset is simply a pair of bike wheels. Bike wheels are made from a range of materials including steel, stainless steel, aluminium, titanium and carbon.  Wheels can be a very cost effective way of upgrading your bike, making it lighter, faster and more responsive. Take a look at our Guide to Wheelsets  for more advice.

Rear Derailleur

Pedals

Pedals need little introduction but are an essential part of the bike that should not be overlooked. Fundamental to efficient power on the bike, pedals come in a vast array of types and sizes to suit different bikes and cycling adventures whether you are cruising around town, attacking a time trial or dropping into steep singletrack descents. From flat to clipless, MTB to road, nylon to magnesium, making sure you have the right pedal for the job can make a difference to your speed, endurance and comfort on the bike, so research all of the options before taking your pick. Take a look at our Guide to Pedals for more advice on which pedals could be best for you.

Handlebars

Handlebars allow you to steer the bike, so it’s important that they provide you with control and confidence. Road bikes typically use narrow drop bars to provide better aerodynamic positioning on the bike when descending, commuter bikes have flat handlebars for a more upright position on the bike giving better visibility of the road ahead, and mountain bikes use wide riser handlebars to assist control around tight bends and over obstacles. If you want to reduce the weight of your bike, look out for featherlight carbon handlebars, but make sure they are still robust enough for your style of riding, in particular MTB handlebars need to take a bit of a pounding without compromising control of the bike. 

Stem

The stem attaches your handlebars to the bike. Stems come in different lengths and rises so you can adjust your riding set up to a position that suits you. It can be tricky to find the right balance, but as a general guide, a shorter stem will give you quicker, more responsive steering but tends to be a less aerodynamic body position, whereas a longer stem gives you a more stretched out and aerodynamic position on the bike. The stem clamps onto your fork’s steerer tube, so you will need to know the size of your fork steerer before you buy. Lightweight carbon and alloy stems are also available if weight savings are important to you. 

Forks

Bike forks hold the front wheel in place on your bike. Extending from the headset of your bike to the hub of the wheel they are usually made up of two stanchions held together by the crown, and the steerer section does exactly what it says on the tin; allows you to turn the wheels and steer the bike. Basic road bike forks are typically made from aluminium but carbon forks can offer weight savings as well as more stiffness and less road vibration. Mountain bike forks usually have suspension to soak up rough off-road terrain, with suspension travel ranging from 80mm up to 200mm. 

Bike parts explained: Forks and stem

Saddles

A comfortable saddle is essential to a good ride. If you are experiencing any discomfort or pain whilst riding, your saddle may be a factor. There are lots of different shapes to choose from; wide, narrow, long, short, standard, cut out. As a general rule of thumb, a flat narrow saddle suits more aggressive stretched out racing riding positions as you need room to move your legs quickly and tend to place less weight onto the saddle itself, whereas a wide, curved saddle is best suited to a more upright riding position to support your weight more effectively.  It’s easy to think that more padding equals more comfort but too much padding can actually cause chaffing if you are riding hard, fast and far, so there’s a balance to be had. 

Seat Posts

The seat post fixes the saddle to the bike frame. Adjustable up and down, you can set the seat post to a height that best suits your riding and desired positioning whether more upright or a racing aerodynamic position. Upgrading your seat post can be a good way to save weight without affecting performance and dropper seat posts are extremely handy for mountain biking, especially cross country and enduro. 

Want to know more about bike components? We're here to help.

If you have any queries or questions about bike components and which upgrades might improve your bike and enhance your riding, get in touch with the Cycle Surgery Team. Pop into one of our Cycle Surgery Stores to have a chat with one of our expert bike gurus, give us a call or chat with us online.


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