A road milling machine includes a sensor mounting system having a first mounting member, which is attached to a first machine component and supports a portion of a position sensor, and a second mounting member attached to a second machine component having a pivotable attachment to a machine frame. An extension member has a first end attached to the second mounting member and a second end including an attachment flange. A unitary ski member has a first end attached to another portion of the position sensor and a second end pivotably attached to the attachment flange. The unitary ski member includes a ground engaging surface that is positioned inboard relative to first and second side plates, which flank a rotor, and has a pivot movement compensation curve. A controller is configured for determining a milling depth of the rotor from measurements obtained by the position sensor.