The tyre test rig at the Institute for Machine Construction and Vehicle Construction at the University of Karlsruhe was surrounded with a heat-insulating metal housing and equipped with a cold installation so that measurements of tyre-road adhesion could be carried out with various tyres on an icy "road". The road is represented by an internal drum in which a driven or braked wheel rolls or slips during blocking. At temperatures lower than - 5 degrees C adhesion coefficients could not be easily reproduced in preliminary tests. The tests were therefore carried out in the temperature range from - 5 degrees C to 0 degrees C. Circumferential and sideways forces on the tyre agreed with the usual parameters on ice, without any significant differences between diagonal and radial tyres. The most important parameter is the surface temperature of the ice. With "unreinforced" tyres (without studs) the maximum sideways force (given an oblique running angle of 4 degrees) is three times as great at minus 4 degrees C as at 0 degrees C. The maximum braking force (given a braking slip of 5 percent) is twice as great. With increasing speed the forces which can be attained decrease sharply. The coefficients of sliding (locked wheel) increase less markedly than the maximum adhesion coefficients as the ice becomes colder. The influence of speed on the coefficients of sliding is limited to the lowest range of speed. Further tests were dedicated to the interaction of circumferential and sideways forces. Finally tests were carried out with reinforced tyres (with studs), but here only measurements on the locked wheel gave reproducible results: the temperature of the ice did not influence the coefficient of sliding; the projection of the studs exerted a considerable influence. Relations have to be drawn up between the results of the tests on the rig and those on the road. /TRRL/

  • Availability:
  • Corporate Authors:

    Verlag fuer Publizataet

    Auf der heide 20
    300 Isernhagen HB, Hannover,   Germany 
  • Authors:
    • WEBER, R
  • Publication Date: 1972


  • German

Media Info

  • Features: Photos; References;
  • Pagination: 6 p.
  • Serial:
    • Strassen und Tiefhau
    • Volume: 26
    • Issue Number: 11/1
    • Publisher: Verlag fuer Publizataet
    • ISSN: 0039-2197

Subject/Index Terms

Filing Info

  • Accession Number: 00097369
  • Record Type: Publication
  • Source Agency: Research Association for Road Communications, W Gr
  • Files: ITRD, TRIS
  • Created Date: Oct 18 1975 12:00AM