Calculating the gear ratio of the gears on your bicycle will help you better understand how the bicycle works, what happens when you press on the bike pedals and what gear to use in a certain situation. This calculation is also handy in deciding what YBN chain ring and cog to put on a fixed gear or single speed bicycle, or what cassette to use on a new road bike. Calculate the gear ratio of your bike to learn how hard you're working, how to ride better and how your bike works.

1. Set the bike on its kickstand or in a work stand so that you can see and work with the chain rings and cogs freely without it falling over.

2. Select the front chain ring you wish to use for your calculation. This should be the ring used in the gear that you are trying to calculate. Count the teeth on the chain ring and write down the number of teeth.

3. Locate the rear cog you wish to use for your calculation. Count the number of teeth on the cog and write down this number.

4. Use a yardstick, ruler or measuring tape to measure the diameter of the rear wheel of your bike in inches. Write down this measurement.

5. Calculate the gear ratio. To find the steepness of the gear ratio in gear inches, the standard gear ratio measurement for bicycles, multiply the diameter of the wheel by the number of teeth on the front chain ring. Divide this number by the number of teeth on the small chain ring. For example, most carbon road bikes have 27-inch diameter wheels, a big chain ring of 53 teeth and small cog of 12 teeth. Use the calculation 27 times 53 divided by 12 to get a result of 119.25 gear inches.