Report on blister formation on test tyres used for skid-resistance measurements (1994 series)

In 1994 the DWW had a batch of tyres manufactured. Some tyres of this batch for skid-resistance measurement began to develop blisters on their treads within a short period of time. This affected the results of the measurements and also reduced the tyre life. The manufacturer has been asked to find the cause of the problem and to indicate how it might be avoided. Blisters are more common in case of dry measurements. Blister formation is more prevalent on roads with a high skid-resistance. Blisters often form during the first 10-15 kilometers of use. If the problem has not manifested itself by then, it usually doesn't at all. The large heat build-up during the measurements causes the formation of blisters in the centre of the tread. An insufficient heat-resistant compound is the cause of the blisters. This proces can be overcome by protecting the compound against heat. Two options are available : use of special anti-degradants or the use of a heat-resistant vulcanizing network.