The RADIALcvt is a multi-parallel power path type of continuously variable transmission (CVT), that consists of only one steel-on-steel friction drive interface in each path.

RADIALcvt features a single friction drive interface in series and at least 6 power split friction drive parallel paths. A constant input radius on the friction drive input make it possible to use a constant clamping force which is provided by springs. Therefore RADIALcvt concept has no hydraulic control system.

The RADIALcvt has a very large radius variation on the friction drive output which provides the ratio variation. Due to the fact that the Radial drivers are clamped between two opposite rotating disks, results in the largely cancelling out of the forces on the Radial drivers. The RADIALcvt’s first ratio is hard geared to eliminate the “kerb test” issue common with push belt CVT’s.

Watch this video to learn more about RADIALcvt.


For further videos, presentations and documents detailing the components, mechanisms and application of the RADIALcvt, please click here


  1. The input power is divided into six parallel power paths with each path encountering only ONE friction drive interface in series (all existing commercial CVT's have at least two friction interfaces in series which produce a compounded friction loss).
  2. The stress in the metal-on-metal contact in the friction drive can be kept below 2GPa because of above parallel power paths and thus avoid expensive materials.
  3. A constant input radius on the friction drive input results in constant clamping force.
  4. A constant clamping force is generated via springs. No hydraulic control system is required.
  5. A very large radius variation on the friction drive output provides the ratio range.
  6. Ratio actuation is electric via 12V DC motor, controlled by PWM (pulse width modulation).
  7. A hard-geared (direct drive which bypasses the variable friction drive ) first ratio is included to overcome the "kerb test" issue common with push-belt CVT’s.
  8. A concept design for a 40kW front wheel drive vehicle (for example a three-cylinder Chevrolet Spark) is available to demonstrate compactness and suitability.
  9. Can serve in a hybrid vehicle and serve as an energy recovery device.
  10. RADIALcvt is scalable.
© 2017 Varibox. All rights reserved.