Abstract: A preassembled drive means unit provided with a support body comprising at least one wheel receiver, which is adapted to receive therein a respective drive means wheel, and an endless drive means, which is adapted to be put around said drive means wheels. This drive means unit comprises a replaceable mounting aid which is arranged in the area of the wheel receiver instead of a drive means wheel. One or a plurality of the drive means wheels can be replaced by the mounting aid. The whole preassembled drive means unit is held in position by the mounting aid, although one or a plurality of the drive means wheels of the drive means unit are not installed. In this way, it will be more easily possible to assemble the drive means unit and to attach the drive means wheels.