MPR is a computer controlled three-contact instrument in which three ‘counterface’ rings drive a smaller diameter roller located in the middle.  The test roller is thus subjected to a large number of rolling contact cycles in a short period of time. The central test roller will experience approximately one million contact cycles per hour.

The MPR is specifically designed to investigate rolling contact fatigue at realistic contact pressures, for liquid and grease lubrication, but can also be used to evaluate new materials and coatings.

More info from manufacturer

Standards and methods Selected literature references

  • SAE ARP6991 MPR Micropitting test method
  • Pitting method (macroscopic pitting)
  • Micropitting method (grauflecken method)
  • (FZG screening method in development)
Literature examples
  • Tribochemical Study of Micropitting in Tribocorrosive Lubricated Contacts: The Influence of Water and Relative Humidity; 18 Nov 2016; Siavash Soltanahmadia, Ardian Morina, Marcel C.P. van Eijk, Ileana Nedelcu, Anne Neville
  • An Analytical Approach for Predicting EHL Friction: Usefulness and Limitations; 06 Jul 2022; J. E. Otero, E. de la Guerra Ochoa, E. C. Tanarro, F. F. Martínez, R. W. C. Urgiles
  • Micropitting Performance of Glycerol-Based Lubricants Under Rolling-Sliding Contact Conditions; 27 Nov 2021; J. G. Z. Tamayo, M. Björling, Y. Shi, B. Prakash, R. Larsson
  • Effect of Relative Humidity on Micropitting Behavior in Rolling–Sliding Contacts with Zinc Dialkyldithiophosphate-Containing Lubricants; 24 Feb 2021; H. Cen, D. Bai, Y. Chao, Y. Li, R. Li
  • Oil Miscible Phosphonium-Phosphate Ionic Liquid as Novel Antiwear and Antipitting Additive for Low-Viscosity Rear Axle Lubricants; 10 Dec 2020; S. Roy, L. Speed Jr., M. Viola, H. Luo, D. Leonard, J. Qu
  • The Effect of Lubricant Composition on White Etching Crack Failures; 29 Nov 2018; B. Gould, N. G. Demas, G. Pollard, J. J. Rydel, M. Ingram, A. C. Greco

more literature utilising the MPR instrument can be found on PCS resources page, or via google scholar