This paper describes work carried out at the Universities of Bradford and Leeds to identify how the performance of power transmission belts may be improved, Part of this study is been an examination of which mechanical properties of the elastomer compound are of significance in determining belt performance, and to identify how the significant elastomer compound properties may be changed to improve belt performance, This work encompasses the examination of belt failure and modelling of belt operation to ensure that the current limits of belt performance are fully understood. It is concluded that such an approach can be of value in improving belt performance.