What are the gears on a bike for?

Bikes have been around for hundreds of years, and some people still think that they’re just for getting from A to B. But the way we use them has changed drastically over the years. The humble bicycle is more than a tool to get around: it’s become an essential part of our daily lives.

If you’ve ever ridden a bike, you know that when the gears shift and spin, it can be pretty noisy. But what exactly is going on in there? We investigate and discuss the details of the gears used on all model and schwinn hybrid bikes.

bike gears

What are the gears on a bike for?

There are generally three types of gears: Chainwheels, cassette wheels, and single ring drive. Gears (Latin for “I move”) make a bike much more versatile than just having one or two speeds! They increase the distance that you can travel at any given time. As well as giving you more time in the saddle, they are also essential to give you quicker acceleration and control. That’s why we have gears on a bike!

Chainwheels gear

A chain wheel is just a set of very large sprockets. These are connected to the bottom bracket (the bike’s axle or frame). Although tightly linked together, they don’t actually touch one another:

The sturdiest bikes use three chain wheels in order to distribute power over each pedal stroke as evenly as possible and with more efficiency than any other method! Traditional wooden rims have this hub design. Although most modern touring road bikes do not, most BMX bikes do. Keep reading Can stationary bike burn belly fat?

The chain wheel has four cogs and it works really simply: The various sprockets in the wheel turn on circular metal teeth that pass right through a series of cords going to your rear cassette or freewheel (see below). On each drive stroke (pedal), you pull these cords down, so one tooth is past the next, then push them up again, keeping this sequence rotating smoothly around its axis. This is called the “chain” because it’s just a chain of cogs and tines or sprockets like the first gear in your car exists as much to smoothly get you uphill that most people associate with gears – they are also known as inputs, outputs, etc.

Cassette wheels gear

The “cassette wheel” is a small sprocket with an internal band that turns in the same way as chains. The difference between them and chain wheels is they have no teeth and so you need to press them down onto another set of smaller cogs – driven by a single chainstay or high tension steel cable, directly like this. This is the entry-level of road bike parts and you can see what such bikes look like. Something similar to this also exists on mountain bikes – it’s called “Spider,” and related versions are seen on BMX bicycles, where they have much smaller effective sprocket sizes.

The cassette itself holds a number of cogs (the cassettes in older gearsets were outside): From ten or fewer up to about thirty-six, with the largest common numbers in modern mountain bike and BMX gear. These are variously known as “clicks,” “teeth,” or simply ‘cogs.’ Each number is supported by a larger band, which alternates with twenty-one individual metal cogs that turn like chains across each other but around circular tracks instead of just moving between pins on their own.

Single ring drive gear

The final part of a bike’s gear system is returning to how you get acceleration/deceleration. The simplest way you can do that is using two chains originally designed with single-speed bicycles in mind – which are used on bicycle drives rather than transmissions or the like. These were made by the same company as cassettes and happen to be called “chainsets” (or they once did). They’re just what we’d commonly call ‘belts’ of small cogs that are identical. The difference is you can’t fit any more than eight there, whereas a wheeling pedal axle can have around sixty (or perhaps only forty) in total – and these often need to be the same size if your pedals work with them at all.

How do bicycle gears work?

The first thing you need to know is bicycles (and drivetrains in general) are not fully automatic motors. You still need some human input, such as pushing the pedals and turning the handlebars, so it can’t be treated any differently to a car or laptop computer where all effort must stop unless operator-initiated otherwise. Motorcycles may have a throttle that allows total deceleration of both wheels, but they’re still controlled by the rider.

The only exception to this is “auto-return”: an accelerator that allows you to ‘put your foot down without having to push a shift lever since it naturally returns the transmission automatically – and once released, can do so for up to ten seconds until power resumes again when required (similarly there may be safeties on clutches ). The same automatic system was at least partly adopted by drivetrains in tandem roadsters and this is how their extra short wheelbase became functional, allowing them to be far more maneuverable all-round than the related ordinary bike.

I use both the push/gear selector for such situations (and permanently set two speeds as well), but it’s still not entirely automatic. In roadster applications that are analogous to car transmission behavior, an accelerator allows clutching when you want it regardless of how much power remains. Instead, cruising with an empty tank on an open road and coasting downhill with your foot off the throttle (to conserve fuel) would be analogous to a sea-level racing engine that won’t downshift. So it’s another specific exception – but functions in much the same way as many other gearboxes do know where there’s often no need to shift anyway when climbing e.g. hill climbs.


Gears are used to change the speed of a bike. They’re also used to make it easier for the rider to shift between gears. A bike with more gears allows the rider to use a higher gear, which will allow them to travel faster, but at a cost. It’s important to know how many gears your bike has so you can choose the right gear for your needs.