How to Use Bike Gear Ratios

How to Use Bike Gear Ratios
A bike's gear ratio refers to a comparison between the number of teeth on the front chain wheels (or pedal wheel) and the cogs on the real wheel. An old-fashioned 10-speed bike, for example, might have two front wheels and five cogs, and each combination would have its own gear ratio. These ratios give you precise information about how many times the rear wheel will turn for every rotation of the pedals. Analyzing that information allows you to determine what gear should be used in what circumstances, taking the guesswork out of gear shifts.

Instructions

Difficulty: Moderate

Step 1
Calculate the basic gear ratio for every gear on the bicycle, setting the rear cog as 1 for every ratio. For example, if a low gear has 22 teeth on the front wheel and 30 teeth on the rear cog, divide 22 by 30 to get 0.73. That creates a ratio of 0.73:1, meaning that for one turn of the pedals, the wheel undergoes a roughly three-quarters of a revolution. Go through all the gears and write down the results.
Step 2
Note which gear is closest to a 1:1 ratio. This should serve as your base. For every turn of the pedals, you get about one revolution of the wheel.
Step 3
Convert your numbers to gear inches. Multiply your results by the size of your bike's wheels. Continuing with our example, if the bike had 26-inch wheels, 0.73 times 26 is 19. That means that with the bike set in that gear, the bike functions as if it were a direct-drive, mono-gear bike with 19-inch wheels. This information tells you how far you travel with every turn of the pedal.
Step 4
Shift into gears in the 40-to-70-inch range for your normal riding.
Step 5
Shift into gears above 70 inches for tackling steep hills.

Tips & Warnings

 
Use hard-to-push gears below 1:1 for training purposes. Try to maintain the same pedaling rpm at these lower ratios.

Article Written By Edwin Thomas

Edwin Thomas has been writing since 1997. His work has appeared in various online publications, including The Black Table, Proboxing-Fans and others. A travel blogger, editor and writer, Thomas has traveled from Argentina to Vietnam in pursuit of stories. He holds a Master of Arts in international affairs from American University.

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