Bicycle Gears

Turn the crank and shift through the gears of a drivetrain like the kind installed at a bicycle’s bottom bracket. Experience how gears balance force and speed: a low gear makes climbing easier, while a high gear lets you travel faster.

The Science Behind It

In a gearbox such as the Pinion system, all the gears are housed in a sealed unit at the bottom bracket. The chain runs from there in a straight line to the rear wheel, so there is no need for a front derailleur or multiple sprockets. Shifting engages a different pair of gears inside the gearbox, changing the gear ratio—that is, how many times the rear wheel turns for each crank revolution. In a low gear, you turn the crank more often and need less force. In a high gear, you turn it less often but travel farther with each revolution. Because the gears are enclosed, they are protected from dirt and weather. You can even shift while standing still.