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.
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.
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).
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.
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 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.
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.
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.