Very few places that you ride your bike will be perfectly flat so when the gradient changes then correct use of your bicycle’s gears will ensure that you have a smooth and comfortable ride. In this guide, we will explain the theory behind changing your gears and share some essential tips to make sure your bike runs efficiently whilst going up and down the sprockets. By the end of this article, you will know how to change gears on a bike like an expert, even if you’re only getting started in the world of cycling.
What Do I Need for This Tutorial?
Simply put, the only thing you will need is a bike with multiple gears! This tutorial does not require any specialist tools or equipment, but as general advice, your bicycle drivetrain should always be well maintained and regularly serviced by somebody with a good knowledge of bicycle mechanics. A well looked the set of gears will be your best friend when out riding but poorly maintained gears can be frustrating and distract you from your ride.
Cassettes and Chainrings, What is the Difference?
On the vast majority of bikes, the gears comprise of chainrings connected to the crank (between 1 and 3) and multiple cassette sprockets connected to the rear hub in a cluster (ranging from 6 to 11 sprockets).
A Cluster of 9 Cassette Sprockets on a Rear Wheel
A “Double” Chainset with 2 Chainrings
These two sets of gear wheels are connected by the chain and by selecting different combinations of chainrings and sprockets it is possible to vary the gear ratio of your bike. The table below shows the number of total gears available with different chainring and cassette sprocket combinations.
Number of Cassette Sprockets
|No of Chainrings
So do more gears mean a better bike? Well not necessarily, as ever it depends on the type of terrain and style of riding you are tackling. For very hilly areas where you will be riding up and down steep gradients, a wide range of gears will help you manage your efforts accordingly, but a higher number of gears usually means extra weight (more sprockets) and more attention required in indexing your gears, so if you are riding predominantly flat terrain then a smaller range of gearing can be a wise choice.
There are also certain applications such as downhill mountain biking where the security of staying on one chainring and hence reducing the likelihood of a dropped chain, outweighs the benefit of more gears.
What Size Sprockets and Chainrings do I Need?
It’s no good having a plethora of gear ratios if none of them is suitable for the type of cycling you’re doing, see below for the typical sprocket and chainring sizes for road and mountain bikes;
- Road Bikes – The traditional chainring setup for road bikes is a double setup with 39 and 53 tooth rings but triple chainsets are also common with the addition of a 30 tooth ring for steep climbs. In recent years the “compact” chainset has gained popularity, this is a 50, 34 tooth combination which gives a slightly wider range of gearing than traditional setups. Specialist time trial bikes built for absolute top speeds sometimes feature chainrings up to 60 teeth in size but these are specialist items and not usual. On the rear wheel, 9, 10 and 11 cogs are the most common configurations with the majority of cassettes covering a range of 12 to 25 tooth cogs. Gearing designed specifically for racing sometimes have a smallest cog of 11 teeth, and cassettes specifically designed for climbing sometimes feature bottom gears of up to 29 teeth.
- Mountain Bikes – The slower speeds experienced in MTBing require much smaller gear ratios than road bikes, chainring sizes typically range from 28-40 which isn’t too different to road gearing, but MTB cassettes feature largest sprockets of up to 40 teeth which give significantly smaller ratios for steep climbing on loose ground. Smallest cassette cogs are as small as 11 or 12 to provide downhill speed meaning that generally there are bigger changes in the resulting ratio when changing gear on a MTB.