A supercharger, comprising: a supercharger housing; a primary supercharger rotor disposed within the supercharger housing, the primary supercharger rotor having a primary supercharger rotor shaft fixed thereto to rotate therewith; a ring gear fixedly attached to an aluminum transmission housing portion of the supercharger housing wherein the ring gear has internal teeth; a sun gear fixed to the primary supercharger rotor shaft to rotate therewith; a planetary gear carrier having a plurality of planetary gear shafts disposed thereon, the planetary gear shafts each being substantially parallel to a carrier primary axis of rotation; a plurality of planetary gears meshingly engaged with the sun gear and the ring gear, the planetary gears substantially equally spaced about the sun gear, each of the plurality of planetary gears to rotate about a corresponding planetary gear shaft of the plurality of planetary gear shafts; a steel rotatable input shaft connectable to the planetary gear carrier, wherein the input shaft is connectable to receive rotational motion and power from a motor; a bearing proximate the planetary gear carrier to support the steel rotatable input shaft, the bearing having: an inner bearing end proximate the planetary gear carrier; an outer bearing end distal to the planetary gear carrier; and an outer race disposed in the aluminum transmission housing; characterized in that the supercharger further comprises: a bearing-contacting resilient annular element axially disposed between the bearing end distal to the planetary gear carrier and a shoulder of the aluminum transmission housing, the resilient annular element configured for: surrounding the rotatable input shaft and being disposed between the outer bearing end of an outer race of bearing and an oil seal, providing an axial force on the outer race to prevent the outer race of the bearing from rotating relative to the aluminum transmission housing; and compensating a ratio of thermal expansion along an axis of rotation of the steel rotatable input shaft between the aluminum transmission housing and the steel rotatable input shaft contained within the aluminum transmission housing. a supercharger housing; a primary supercharger rotor disposed within the supercharger housing, the primary supercharger rotor having a primary supercharger rotor shaft fixed thereto to rotate therewith; a ring gear fixedly attached to an aluminum transmission housing portion of the supercharger housing wherein the ring gear has internal teeth; a sun gear fixed to the primary supercharger rotor shaft to rotate therewith; a planetary gear carrier having a plurality of planetary gear shafts disposed thereon, the planetary gear shafts each being substantially parallel to a carrier primary axis of rotation; a plurality of planetary gears meshingly engaged with the sun gear and the ring gear, the planetary gears substantially equally spaced about the sun gear, each of the plurality of planetary gears to rotate about a corresponding planetary gear shaft of the plurality of planetary gear shafts; a steel rotatable input shaft connectable to the planetary gear carrier, wherein the input shaft is connectable to receive rotational motion and power from a motor; a bearing proximate the planetary gear carrier to support the steel rotatable input shaft, the bearing having: an inner bearing end proximate the planetary gear carrier; an outer bearing end distal to the planetary gear carrier; and an outer race disposed in the aluminum transmission housing; an inner bearing end proximate the planetary gear carrier; an outer bearing end distal to the planetary gear carrier; and an outer race disposed in the aluminum transmission housing; characterized in that the supercharger further comprises: a bearing-contacting resilient annular element axially disposed between the bearing end distal to the planetary gear carrier and a shoulder of the aluminum transmission housing, the resilient annular element configured for: surrounding the rotatable input shaft and being disposed between the outer bearing end of an outer race of bearing and an oil seal, providing an axial force on the outer race to prevent the outer race of the bearing from rotating relative to the aluminum transmission housing; and compensating a ratio of thermal expansion along an axis of rotation of the steel rotatable input shaft between the aluminum transmission housing and the steel rotatable input shaft contained within the aluminum transmission housing. a bearing-contacting resilient annular element axially disposed between the bearing end distal to the planetary gear carrier and a shoulder of the aluminum transmission housing, the resilient annular element configured for: surrounding the rotatable input shaft and being disposed between the outer bearing end of an outer race of bearing and an oil seal, providing an axial force on the outer race to prevent the outer race of the bearing from rotating relative to the aluminum transmission housing; and compensating a ratio of thermal expansion along an axis of rotation of the steel rotatable input shaft between the aluminum transmission housing and the steel rotatable input shaft contained within the aluminum transmission housing.