Some, mainly utility, bicycles use hub gears with between 3 and 14 ratios, but most use the generally more efficient dérailleur system, by which the chain is moved between different cogs called chainrings and sprockets in order to select a ratio.
Some utility use hub gears with between 3 and 14 ratios. This is mainly. Some utility is bicycles. Most use the generally more efficient dérailleur system. The chain is moved between different cogs. These different cogs are called chainrings and sprockets in order. This was to select a ratio by the generally more efficient dérailleur system.