A bearing mounting system for use in a gas turbine engine having a low pressure turbine supported on a low pressure shaft through a support rotor comprises a low pressure turbine case, a forward bearing and an aft bearing, and a forward support structure and an aft support structure. The low pressure turbine case surrounds the low pressure turbine. The forward bearing and the aft bearing are positioned on the low pressure shaft to straddle the support rotor. The forward support structure and the aft support structure connect the forward bearing and the aft bearing, respectively, to the low pressure turbine case. The low pressure shaft extends axially between the forward bearing and the aft bearing. In one embodiment, the turbine comprises a plurality of adjacent rotor disks, and the support rotor comprises a conical support connecting one of the rotor disks with the shaft.