A crane comprising: a carrier unit having a chassis, tires connected to the chassis, a carrier deck and outriggers, the outriggers movable to a deployed condition in which the outriggers engage an underlying support surface and lift the tires from the support surface such that the outriggers support the carrier unit, and a retracted condition in which the outriggers are disengaged from the support surface and the tires are engaged with the support surface, such that the tires support the carrier unit; a superstructure mounted on the carrier unit, the superstructure comprising a telescoping boom; a slope sensor operably connected to the carrier unit and configured to detect a pitch and/or a roll of the carrier unit during a lift operation; and a system for monitoring a load lifted by the telescoping boom, the system configured to: determine the current load lifted by the telescoping boom; receive pitch and/or roll information of the carrier unit from the slope sensor; adjust coordinates of the crane in a coordinate system based on the pitch and/or roll information; determine a transformed operating radius (R') using the adjusted coordinates; and compare the current load lifted to a rated capacity at the transformed operating radius (R'), characterized in that the system is configured to monitor the load lifted with the outriggers in the retracted condition, and wherein the system is further configured to control vertical extension of the outriggers based on the pitch and/or roll information during movement of the outriggers to the deployed condition for leveling the carrier unit. a carrier unit having a chassis, tires connected to the chassis, a carrier deck and outriggers, the outriggers movable to a deployed condition in which the outriggers engage an underlying support surface and lift the tires from the support surface such that the outriggers support the carrier unit, and a retracted condition in which the outriggers are disengaged from the support surface and the tires are engaged with the support surface, such that the tires support the carrier unit; a superstructure mounted on the carrier unit, the superstructure comprising a telescoping boom; a slope sensor operably connected to the carrier unit and configured to detect a pitch and/or a roll of the carrier unit during a lift operation; and a system for monitoring a load lifted by the telescoping boom, the system configured to: determine the current load lifted by the telescoping boom; receive pitch and/or roll information of the carrier unit from the slope sensor; adjust coordinates of the crane in a coordinate system based on the pitch and/or roll information; determine a transformed operating radius (R') using the adjusted coordinates; and compare the current load lifted to a rated capacity at the transformed operating radius (R'), characterized in that the system is configured to monitor the load lifted with the outriggers in the retracted condition, and determine the current load lifted by the telescoping boom; receive pitch and/or roll information of the carrier unit from the slope sensor; adjust coordinates of the crane in a coordinate system based on the pitch and/or roll information; determine a transformed operating radius (R') using the adjusted coordinates; and compare the current load lifted to a rated capacity at the transformed operating radius (R'), characterized in that the system is configured to monitor the load lifted with the outriggers in the retracted condition, and wherein the system is further configured to control vertical extension of the outriggers based on the pitch and/or roll information during movement of the outriggers to the deployed condition for leveling the carrier unit.