A system comprising a speed sensor and a protective sleeve, the speed sensor having: a permanent magnet configured to generate a magnetic field, at least one sensor element that is provided in the region of the magnetic field and configured to measure the speed of an encoder element assigned to the speed sensor and to convert it into an electrical signal, a plastic overmoulding that is arranged around the permanent magnet and the sensor element and configured to protect the parts thus encompassed and fix them in place, the speed sensor being configured to be inserted into the protective sleeve, the protective sleeve having: an upper end portion that is configured to take electrical connections of the speed sensor out of the protective sleeve, a side wall that connects to the upper end portion and extends in the direction of a longitudinal axis, and a lower end portion that connects to the side wall, the protective sleeve having a recess in its lower end portion, and the lower end portion having a bottom face that is configured to delimit the side wall in the direction of the longitudinal axis of the protective sleeve, and the recess in the lower end portion of the protective sleeve being located in this bottom face and, once the speed sensor has been inserted into the protective sleeve, being filled by the plastic overmoulding such that the plastic overmoulding and the bottom face terminate flush with one another, in addition, the plastic overmoulding further having a projection that is designed in such a way that it can be inserted into the recess formed in the lower end portion of the protective sleeve and, after insertion, terminates flush with the bottom face of the lower end portion of the protective sleeve, and the plastic overmoulding is performed such that, once the speed sensor has been inserted into the protective sleeve, it has a layer of plastic of a defined layer thickness d between the sensor element and the bottom face of the protective sleeve. a permanent magnet configured to generate a magnetic field, at least one sensor element that is provided in the region of the magnetic field and configured to measure the speed of an encoder element assigned to the speed sensor and to convert it into an electrical signal, a plastic overmoulding that is arranged around the permanent magnet and the sensor element and configured to protect the parts thus encompassed and fix them in place, the speed sensor being configured to be inserted into the protective sleeve, the protective sleeve having: an upper end portion that is configured to take electrical connections of the speed sensor out of the protective sleeve, a side wall that connects to the upper end portion and extends in the direction of a longitudinal axis, and a lower end portion that connects to the side wall, the protective sleeve having a recess in its lower end portion, and the lower end portion having a bottom face that is configured to delimit the side wall in the direction of the longitudinal axis of the protective sleeve, and the recess in the lower end portion of the protective sleeve being located in this bottom face and, once the speed sensor has been inserted into the protective sleeve, being filled by the plastic overmoulding such that the plastic overmoulding and the bottom face terminate flush with one another, in addition, the plastic overmoulding further having a projection that is designed in such a way that it can be inserted into the recess formed in the lower end portion of the protective sleeve and, after insertion, terminates flush with the bottom face of the lower end portion of the protective sleeve, and the plastic overmoulding is performed such that, once the speed sensor has been inserted into the protective sleeve, it has a layer of plastic of a defined layer thickness d between the sensor element and the bottom face of the protective sleeve. an upper end portion that is configured to take electrical connections of the speed sensor out of the protective sleeve, a side wall that connects to the upper end portion and extends in the direction of a longitudinal axis, and a lower end portion that connects to the side wall, the protective sleeve having a recess in its lower end portion, and the lower end portion having a bottom face that is configured to delimit the side wall in the direction of the longitudinal axis of the protective sleeve, and the recess in the lower end portion of the protective sleeve being located in this bottom face and, once the speed sensor has been inserted into the protective sleeve, being filled by the plastic overmoulding such that the plastic overmoulding and the bottom face terminate flush with one another, in addition, the plastic overmoulding further having a projection that is designed in such a way that it can be inserted into the recess formed in the lower end portion of the protective sleeve and, after insertion, terminates flush with the bottom face of the lower end portion of the protective sleeve, and the plastic overmoulding is performed such that, once the speed sensor has been inserted into the protective sleeve, it has a layer of plastic of a defined layer thickness d between the sensor element and the bottom face of the protective sleeve.