The chain drive offered a very simple and inexpensive method of providing for a completely flexible range of speed ratios.
The chain drive is like the direct-geared except that it substitutes a chain and two sprockets for two gears.
The very substantial advantages of the chain drive were not, however, obtained at no cost.
The chain drive should be retained, but one of the cranks removed and a handle substituted for the remaining pedal.
Some of the light-weight models are using belt drive, but chain drive is generally conceded to be superior.
There has been considerable difference of opinion as regards the comparative efficiency of chain drive and belt drive.
They are likely to have straight spur transmission gears, and a straight spur or chain drive, all carefully protected from dust.