Due to general safety reasons and an increasing individual demand on more traffic safety, winter tires become more and more important. This evolution results in a rising requirement of the customers concerning the tire performance on the one hand and the effort of the tire industry for improving the tire characteristics on the other hand. For engineering winter tires in an effective way, the friction influencing factors as well as the contact mechanics should be well known. Normally the design and development of tires is strongly based on vehicle tests, but in modern tire development processes the simulation as well as the experimental investigation of tires and tire components in the lab become more popular. This strategy especially plays an important role for reducing the time of development cycles but also the development costs. With simulation and experiments in lab, new challenges come up which have to be solved. Lab experiments compete with totally different problems: First of all the environmental influence like temperature and humidity have to be controlled. Furthermore the test tracks used inside, must be comparable to the proving ground outside, hence the properties of snow and ice have to be investigated in detail. Therefore it is very important to understand the formation of snow and ice but also finding characteristics of both materials which can be identified and measured with mobile measurement devices outside on the test track and inside in the lab.

Within this publication a general overview of the tire tread block test method as well as the test rig will be given which are used for identifying relevant tread block friction mechanisms on snow and ice. The results of the measurement will be shown and the acting friction phenomena will be explained. Furthermore different approaches for characterizing snow and ice are presented.