Complex sentence: 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.
Split into simpler sentences: Some, mainly utility, bicycles use hub gears with between 3 and 14 ratios. However most systems 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.