How do Bicycle Gears Work?
A single speed bicycle has one chainring in the front, and one cog in the back. The “number of gears” a bicycle has is calculated by multiplying the number of gears on the front (by the pedals), and the gears on the back (on the rear wheel). This is the number of possible combinations, not the number of actual “gears” (as in the physical metal rings with teeth). So an old single-speed “Beach cruiser” bike has one gear in the front (the chainring), and one gear in the back (a sprocket or cog). 1 x 1 = 1 . . . so it’s a single speed! Many of the bikes made in the 1970s bike boom were 10-speed. They have two gears on the front (the chainrings), and five gears on the back (sprockets or cogs, and all five of them taken together are called a “freewheel”). 2 x 5 = 10 . . . the famous ten speed! Bicycles today aren’t much different. Three gears on the front (chainrings), and six gears on the front is very common now. 3 x 6 = 18 speed! So the difference between a 10-speed bike and an 18-speed b
