The positive linkage among chain and gear wheel permits constant speeds despite having torque fluctuations and incredibly good reproducibility of speeds. Standard variable gear devices force the transmission component through the use of excessive force - this is unnecessary and decreases the amount of efficiency.
PIV CHAIN CONVERTORS Variable Chain Drives Adjustable chain drives apply a lever system, which applies just as much strain 
on the slat chain as necessary. This outcomes in low operating temperatures, long life, high power density and a great efficiency - actually in the partial load range.