To provide a measuring device for a measured variable of a front car especially a tractor and/or a measured variable of a trailer or a semitrailer coupled on to the front car, wherein no additional or very high reforming costs are generated for an end user regarding a used sensor device.

In this measuring device for a measured variable of a front car 1 especially a tractor and/or a measured variable of a trailer or a semiconductor 2 coupled on to the front car, in addition to a coupling device for force transmission between the front car and the trailer or the semitrailer, at least one connecting device 3, 6, 7, 11, 12, 13 is provided. The connecting device 3, 6, 7, 11, 12, 13 incorporates at least one first measuring means 5 for measuring the measured variable of the front car and/or at least one second measuring means 4 for measuring the measured variable of the trailer or the semitrailer.