The present invention relates to dimensionally stable compositions comprising A) 50 to 70 parts by weight of at least one aromatic polycarbonate, B) 16 to 30 parts by weight of at least one polyalkylene terephthalate, C) 4 to 30 parts by weight of at least one mineral filler based on talc, D) 0.1-8.0 parts by weight of additives, with component D comprising at least one mould release agent and at least one stabilizer and with the sum of the parts by weight of components A-D making 100. The present invention further relates to the use of the thermoplastic moulding compounds for producing dimensionally stable preforms and mouldings, and also to the preforms and mouldings obtainable from the thermoplastic moulding compounds. The preforms and mouldings find preferred application in motor vehicle construction, more preferably as exterior components.