||Premature failure is the major problem encountered in the operation of truck brake discs. The present study was carried out with the aim of developing brake discs with increased lifespans, so as to improve the safety and reliability of these components. To this end, two aspects, namely design and material, were investigated. In order to understand the different damage modes, we studied the behaviour of a grey cast iron brake disc combined with two semi-metallic pads under extreme conditions. A coupled numerical–experimental approach enabled us to determine the critical thermomechanical loadings associated with braking-induced metallurgical phase transformations.