NOISE EMISSION FROM RETREADED TIRES

Due to stringent requirements on vehicle power unit noise and a lack of control of tire/road noise, the latter has become the dominating noise component of new vehicles in Europe at speeds above 30-50 km/h. In order to address this problem, a supplement to a European Union directive including noise emission limits for noise from new vehicle tires is underway. This proposed tire noise regulation does not (so far) include noise limits for retreaded tires. In Sweden, around 25% of the car tires sold on the market are retreaded. The corresponding number for retreaded truck tires is 50%. Values for most other countries may be a little lower regarding car tires but approximately the same for truck tires. In 1998, for example, 57% of the medium truck replacement tires in North America were retreaded. This implies that a very significant part of the vehicles in traffic run on retreaded tires. Most investigations on noise emission from tires have been based on sets of new tires and in the literature it is not easy to find data on retreaded tires. This study therefore presents data on the noise emission of 12 retreaded car tires, both for summer and for winter use, as compared with corresponding data for a large number of tires in new condition. The differences in noise emission between a group of retreaded tires and a group of factory new tires are studied here. Furthermore, some individual retreaded tires are compared to new tires having similar tread patterns. For the covering abstract see IRRD E104312.