The Challenge range of Shaft Mounted Speed Reducers (SMSRs) stands tall amongst the crowd.

Packed full of attention to detail, the Challenge SMSRs deliver performance in the harshest of applications.

Shaft mounted drives remove the need for couplings, mounting plinths and have infinitely variable ratios due to the belt drive. They are also incredibly simple to fit and can be mounted in any position as no motor base is required.

Challenge manufactures two versions; the metric based SMSR and the imperial (inch) based TXT.


  • Available in sizes B to L
  • Grip-Loc hubs available for simple installation and removal
  • Includes complete torque arm assembly
  • Interchangeable with most other manufacturers
  • Production line manufacturing guarantees tolerances and consistent quality.
  • Gears produced on German manufactured hobbing centres to achieve the highest quality helical gear components.
  • Pinions; 8620 steel
  • Gears; 20MnCr5 steel
  • All gears are ground
  • Final heat treatment includes gas carburising to a depth of 1mm, then grinding to DIN class 6.
  • Castings crack tested
  • All units test run prior to final quality control checks
  • Full traceability guaranteed with unique Challenge serial number.
  • Backstops also available to prevent reversing
  • Drive ratios exceed 150:1 with a belt drive
  • Double lipped oil seals used throughout
  • Standard ball and cylindrical roller bearings used – in stock around the world

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