Having chainring blocks, a chain or cranks alone will not be enough. In order to shift gears while riding a bicycle, you must also have gear shift handle(s). Usually if there is more than 16 gears, the rear gearshift handle is mounted on the right side, and the front gearshift handle is mounted on the left. When choosing new handles, the most important thing is to know how many front and rear gears your bicycle has. As technology advances, gear shift handles become stronger, lighter, and provide smoother gear shifting. Cheaper models are integrated with brake handles, more expensive - have separate handles. Some high-end models use I-Spec technology, such as Shimano Deore XT and XTR, where the gear shifting handles are mounted directly to the brake levers. This is done in order to leave more space on the handlebar, for example, for the fork lock lever, and to make the installation of the grips faster and more convenient.
