The invention relates to a method for producing a combined service brake cylinder and spring-loaded brake cylinder (1) for a brake system of a vehicle, having the following steps: a) under different operational conditions, measuring and recording force-actuation path characteristic curves (C1, C2, C3, C4) of the brake system with all the actuating elements which can be actuated by the storage spring (11) of the spring-loaded brake cylinder (5); b) measuring and recording force-actuation path characteristic curves (F1, F2, F3, F4) of different storage springs (11) for potential use in the spring-loaded brake cylinder (5); c) determining the minimum necessary actuation stroke (H3) of the piston (9) of the spring-loaded brake cylinder (5) and the minimum necessary spring force for a storage spring (11) to effect a parking brake function by means of the spring-loaded brake cylinder (5) by determining the intersection points of the force-actuation path characteristic curves (C1, C2, C3, C4) of the brake system with the force-actuation path characteristic curves (F1, F2, F3, F4) of the different storage springs (11); d) selecting the storage spring (11) which generates an actuation force sufficient to effect a parking brake function in the most unfavourable operating state of the brake system and with respect to maximum vehicle weight with the smallest possible actuation stroke (H3); and e) producing the combined service brake cylinder and spring-loaded brake cylinder (1) with the storage spring (11) selected in step d) and the dimensions resulting from the smallest possible actuation stroke (H3) of the piston (9) of the spring-loaded brake cylinder (5).