 Epicyclic gearing or planetary gearing is a gear system consisting of one or more outer gears, or planet gears, revolving about a central, or sun gear. Typically, the planet gears are mounted on a movable arm or carrier which itself may rotate relative to the sun gear. Epicyclic gearing systems also incorporate the use of an outer ring gear or annulus, which meshes with the planet gears. gear

Advantages  Compared to conventional gearboxes has smaller dimensions  Easier to sort through the constant rounds of shot  Greater durability than conventional bikes in gear  Easy to achieve high transmission ratio due to the size

Disadvantages  More expensive than conventional production of gearboxes  More complex than conventional transmission

Drawing of the planetary gear

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