UDL Mechanical Speed Variator


UDL disc mechanical derailleurs operate on oval discs to provide continuously variable ratios. The output speed ranges from 76% to 12% of the motor input speed while scaling torque proportional to deceleration with an average efficiency of 84%. Mechanical designers appreciate the simplicity, low cost, low maintenance, and reliability of these compact mechanical transmissions.


  • 3 sizes – IEC 63B5, 71B5, 80B5 input/output.
  • 6 to 1 gear shifting range.
  • The rotary transmission design is stable, quiet, and efficient.
  • Lubrication – ATF (Automatic Transmission Fluid).
  • “Fisheye” oil-level sight glass.
  • Replaces Bonfiglioli V0.25F63 D11 P63 = UDL002. V.05F71 d14 P71 = UDL005, V1F80 D19 P80 = UDL010.
  • Replaces Motovario TXF002 =  UDL002, TXF005 = UDL005, TXF010 = UDL010.
  • Replaces SITI MK2 = UDL002, MK5 = UDL005, MK10 = UDL010.
  • Ships same day from Missouri distribution center.