A planetary gear system comprising: a sun gear located along a main axis and having first and second helical teeth arranged at opposite angles; a ring gear having its center located along the main axis and having first and second helical teeth arranged at opposite angles; first planet pinions having helical teeth engaged with the first helical teeth of the sun and ring gears (2, 4); second planet pinions having helical teeth engaged with the second helical teeth of the sun and ring gears (2, 4); a carrier located between the sun and ring gears (2, 4) and supporting the first and second planet pinions (8, 10) such that they rotate about offset axes that are substantially parallel to the main axis, the carrier having a coupling at which torque is exerted on the carrier, the carrier further having a first torque transfer path (a) between the coupling and the first planet pinions and a second torque transfer path (b) between the coupling and the second planet pinions, with the first torque transfer path (a) being stiffer than the second torque transfer path (b); one of the sun gear or ring gear being mounted around the main axis such that said one gear (2, 4) can shift axially relative to the first and second planet pinions (8, 10) to assume a neutral position in which the axial forces generated by the mesh of the helical teeth with said one gear are substantially equal and opposite and the torque transferred through the first pinions is generally equal to the torque transferred through the second pinions; wherein the first and second planet pinions (8, 10) are organized in sets, there being within each set a first planet pinion and a second planet pinion, with the offset axes of the two planet pinions (8, 10) in the set being generally aligned; wherein the carrier comprises: a first end wall located opposite and supporting the first planet pinions; a second end wall located opposite and supporting the second planet pinions; characterized by that the second planet pinions being detached from the first planet pinions; and the planetary gear system further comprising: webs connecting the first and second end walls (20, 22) and extending between the sets of first and second planet pinions (8, 10); wherein the first torque transfer path (a) passes through the first end wall and the second torque transfer path (b) passes through at least the webs and the second end wall; and wherein each first and second planet pinion (8, 10) is carried by a flexpin assembly (32, 34) that is mounted on the carrier end wall (20, 22) opposite which the planet pinion (8, 10) is located. a sun gear located along a main axis and having first and second helical teeth arranged at opposite angles; a ring gear having its center located along the main axis and having first and second helical teeth arranged at opposite angles; first planet pinions having helical teeth engaged with the first helical teeth of the sun and ring gears (2, 4); second planet pinions having helical teeth engaged with the second helical teeth of the sun and ring gears (2, 4); a carrier located between the sun and ring gears (2, 4) and supporting the first and second planet pinions (8, 10) such that they rotate about offset axes that are substantially parallel to the main axis, the carrier having a coupling at which torque is exerted on the carrier, the carrier further having a first torque transfer path (a) between the coupling and the first planet pinions and a second torque transfer path (b) between the coupling and the second planet pinions, with the first torque transfer path (a) being stiffer than the second torque transfer path (b); one of the sun gear or ring gear being mounted around the main axis such that said one gear (2, 4) can shift axially relative to the first and second planet pinions (8, 10) to assume a neutral position in which the axial forces generated by the mesh of the helical teeth with said one gear are substantially equal and opposite and the torque transferred through the first pinions is generally equal to the torque transferred through the second pinions; wherein the first and second planet pinions (8, 10) are organized in sets, there being within each set a first planet pinion and a second planet pinion, with the offset axes of the two planet pinions (8, 10) in the set being generally aligned; wherein the carrier comprises: a first end wall located opposite and supporting the first planet pinions; a second end wall located opposite and supporting the second planet pinions; characterized by that the second planet pinions being detached from the first planet pinions; and the planetary gear system further comprising: webs connecting the first and second end walls (20, 22) and extending between the sets of first and second planet pinions (8, 10); wherein the first torque transfer path (a) passes through the first end wall and the second torque transfer path (b) passes through at least the webs and the second end wall; and wherein each first and second planet pinion (8, 10) is carried by a flexpin assembly (32, 34) that is mounted on the carrier end wall (20, 22) opposite which the planet pinion (8, 10) is located.