Function of Drum Gear in a bike

Function of Drum Gear in a Bike

Motorcycle transmissions are made up of gears in constant mesh. Because of this, there are no syncros to speed up the gears. The gears are already spinning. To change between gears you need some kind of gear shifter mechanism to go along with that gear shift lever.

Gear shifters come in three different types.

1.      Drum Shifters

·         Drum Slider Forks

·         Shaft Slider forks

2.       Cam Plate and Shift Quadrant Shifter

3.       Ball Lock Shifter

In a motorcycle, instead of moving a lever back and forth with your hand (as in a car), you move a lever up and down with your foot. These motions are rotating a ratcheting drum.

There are grooves cut into the drum. These grooves can do one of two things:

·         If the drum is located away from the transmission's gears, the grooves control standard control rods.

·         If the drum is located next to the gears, the grooves directly move the gear selector fork, and no control rods are needed. This seems to be the more common technique because it has fewer parts and is more compact.

So, when you move the lever, it rotates the drum one increment (for example, 50 degrees). This rotation causes the rods or forks to move according to the grooves in the drum, changing the gears.

Because of the drum, you have to shift in sequence. There is no skipping, for example, from first gear to third. You must always go through second gear to get to third gear. It is the same when downshifting. The advantage of this system is that shifting mistakes are impossible. You always go to the next gear.

                                                                                         Wajahat Jamil

                                                                                         Third Year (IM-115)

                                                                                         2012-2013