It has been argued that the grip of winter tyres on ice and snow deteriorates with age to such an extent that winter tyres above a certain age e.g. 10 years should be forbidden to use. Little research data do however exist. This investigation has been carried out by the Swedish National Road and Transport Research Institute (VTI) in order to get a better background for legal decisions. The results would also be of use for ordinary consumers as a guidance. This is the first of three part studies. The aim of the investigation is to investigate the correlation between ice grip of winter tyres and their age, tread depth and tread rubber hardness and for studded tyres also stud protrusion and stud force. The investigation comprises 20 studded and 33 non studded winter tyres and 4 summer tyres mainly of the in Sweden popular brands Gislaved, Michelin and Good Year of size 185/65-R15. Most of the tyres had been driven in ordinary traffic and varied in age from three (1998) to fifteen (1986) years. A small number of new winter tyres were also tested. As reference some new summer tyres were tested as well. The steering and braking performance of the tyres has been measured in a special climate controlled indoor high speed flat bed test facility developed by the VTI. The tests in this part investigation were carried out on smooth black ice near zero degrees centigrade (-3°C). Investigations on rough ice and wet ice will follow in the next few years. The new winter tyres were clearly better than the average of the older tyres. In the age range 5 to 15 years however no significant influence of age on the ice friction of winter tyres could be found regardless of if they were studded or not. The results also show that on this surface studded tyres as a group still are superior to non studded tyres including the specialised studless winter tyres often called "friction tyres". The differences in friction within the groups are however quite large. The test results from this investigation do not answer the question whether or how the performance of a stored unused tyre is reduced with time. Results from an earlier investigation by VTI is however presented in this report. The results here showed no deterioration within 3 years of storage.