Bicycle Drivetrain 101: How to Shift Gears on a Bike

Last updated: Mar, Fri, 2017

The combination of two different sized cogs and a chain lets you power down hills, cruise on the flat and climb up a gradient. What a great invention. But, changing gears is a matter where the chain runs between many different cogs. These cogs are both turning between your feet and attached to the rear wheel, giving the rider a sometimes bewildering number of gears to choose between.


The drivetrain of the bike consists of all the bits that you use to push (or pull) the bike along, we’ll get to the different terminology. The key components are:

How the gears work

As outlined above, you probably have two sets of gears on your derailleur-equipped bicycle. The front derailleur moves the chain across the chainrings. The rear derailleur moves the chain across the cogs of the freewheel.

Your point of contact with your gear systems is a ‘shifter’ of some type. A cable connects each shifter to its derailleur. Tension on the cable pulls the derailleur one direction, and a spring in the derailleur pulls it in the other direction.

Many shifters are marked in some way, often numbered or with an ‘H’ for the high gear and an ‘L’ for the low gear.

This can be confusing for some people that the highest gears correspond to the physically largest chainring but the physically smallest cog. It is better to ignore the size of the gears and remember that the inner gears are lower and the outer gears are higher in both front and back.

Riding a bike with gears can be quite a daunting experience. With practice and understanding, though, the relationship between you and your steed can become a truly satisfying experience. Try not to be daunted by your gears.

When & Where & How to Use

Don’t be afraid to experiment with different gear combinations. Change through the gears one or two at a time, a little understanding can go a long way.

Every shifter/derailleur combination is different, develop a feel for yours. As you get familiar with the feel of the gears, you can begin to anticipate what gear combination will be best for upcoming terrain and obstacles.

Here are a few hints and tips:


Many beginners are unaware that certain combinations of gears should not be used. There are 2 most extreme combinations of gears to avoid.

This results puts a lot of stress on the chain, rapidly increased component wear and potentially the chain coming off and jamming, even on an otherwise correctly set-up and maintained bike.