A power transmission system for a wind turbine comprises a gearbox and generator. The gearbox includes a gearbox housing and gearbox output member. The generator includes: a generator housing having a drive-end side and non-drive-end side, the drive-end side being coupled to the gearbox housing; a stator supported by the generator housing; a rotor having a rotor shaft coupled to the gearbox output member and a rotor body coupled to the rotor shaft; a non-drive-end shield coupled to the non-drive-end side; a spindle extending from the non-drive-end shield in the axial direction; and at least one generator bearing positioned between the rotor shaft and spindle. The generator bearing(s) support the gearbox output member and rotor shaft. A method of assembling or servicing such a power transmission system is also provided.