Types of Shifters
Regardless of shifter style or type of bike, one shifter controls the front derailleur, and one controls the back.
Road Bike Shifters
Most road bikes have shifters integrated into the brake levers of the bike. They’re easy to reach and in your field of vision, so you don’t have to take your eyes off the road to shift. Older and lower-budget road bikes have shifters mounted on either side of the stem, on the downtube, or in the bar ends.
Mountain Bike Shifters
There are two styles of shifters popular on mountain bikes:
Thumb shifters have two levers for each hand—one lever moves the chain up through the gears and one moves the chain down. On one hand, the top lever makes the gears harder, and on the opposite hand the top shifter makes the gears easier.
Grip shifters let you switch gears by twisting the indexed grip of your bike forward or backward. Like with thumb shifters, twisting one way moves the chain up through the gears and twisting the opposite way moves the chain down.