An apparatus comprising: a first rotational component of a gas turbine engine, wherein the first rotational component is a mounting compressor wheel including a rim and an elongated connecting element fixed thereto and extending therefrom substantially on an axis of rotation of the apparatus; a second rotational component of the gas turbine engine, wherein the second rotational component is a first compressor wheel including a rim and a bore extending therethrough along the axis of rotation; a third rotational component of the gas turbine engine, wherein the third rotational component is a second compressor wheel including a rim and a bore extending therethrough along the axis of rotation; a first mounting structure engaged to the rim of the second rotational component on a side of the second rotational component opposite the first rotational component; a second mounting structure engaged to the rim of the third rotational component on a side of the third rotational component opposite the first rotational component; wherein the elongated connecting element includes a first elongate portion extending through the bore of the second rotational component for connection with the first mounting structure in tension so as to compress the second rotational component between the first mounting structure and the first rotational component; wherein the elongated connecting element includes a second elongate portion extending through the bore of the third rotational component for connection with the second mounting structure in tension so as to compress the third rotational component between the second mounting structure and the first rotational component; wherein clamping engagement of the rims of the first, second and third rotational components (230, 210, 222) rotatably interconnects the rotational components (230, 210, 222) to one another for torque transmission through suitable coupling arrangements at the rims that is sufficient to maintain the interconnection of wheels (210, 212, 220, 222, 230) during engine operation, characterized in that the connecting element is an elongated rod having a hollow interior for receiving a shaft, the elongated rod extending from a first end fixedly connected to the mounting compressor wheel to an opposite second end removably connected to the mounting structure (250, 252). a first rotational component of a gas turbine engine, wherein the first rotational component is a mounting compressor wheel including a rim and an elongated connecting element fixed thereto and extending therefrom substantially on an axis of rotation of the apparatus; a second rotational component of the gas turbine engine, wherein the second rotational component is a first compressor wheel including a rim and a bore extending therethrough along the axis of rotation; a third rotational component of the gas turbine engine, wherein the third rotational component is a second compressor wheel including a rim and a bore extending therethrough along the axis of rotation; a first mounting structure engaged to the rim of the second rotational component on a side of the second rotational component opposite the first rotational component; a second mounting structure engaged to the rim of the third rotational component on a side of the third rotational component opposite the first rotational component; wherein the elongated connecting element includes a first elongate portion extending through the bore of the second rotational component for connection with the first mounting structure in tension so as to compress the second rotational component between the first mounting structure and the first rotational component; wherein the elongated connecting element includes a second elongate portion extending through the bore of the third rotational component for connection with the second mounting structure in tension so as to compress the third rotational component between the second mounting structure and the first rotational component; wherein clamping engagement of the rims of the first, second and third rotational components (230, 210, 222) rotatably interconnects the rotational components (230, 210, 222) to one another for torque transmission through suitable coupling arrangements at the rims that is sufficient to maintain the interconnection of wheels (210, 212, 220, 222, 230) during engine operation, characterized in that the connecting element is an elongated rod having a hollow interior for receiving a shaft, the elongated rod extending from a first end fixedly connected to the mounting compressor wheel to an opposite second end removably connected to the mounting structure (250, 252).