Openable vehicle roof with a folding top

The roof has a folding cover with rods (1) and textile cover. A material tensioner (6) associated with the rods is held tensioned in the closing position of the cover and can be moved between the tension and a released position through a secondary actuator (22). The tensioner is swivel mounted on the main guide rod of the rods which is swivel mounted on the vehicle body and can be adjusted through a main actuator (5). The tension rod linkage (17) has two articulated tension rods (18,19) of which the second is connected for articulation with the main guide rod. In the tensioned position the two tension rods are in the over dead centre position.