Starter for a combustion engine of a motor vehicle, comprising: - an electric motor comprising a yoke and a rotor mounted on a shaft , - a drive shaft able to be driven to rotate by said rotor , - a speed reducer of the epicyclic type mounted between the rotor shaft and said drive shaft , - said speed reducer comprising a ring gear forming an annulus gear of said speed reducer , a pinion rotationally coupled to said rotor shaft forming a sun gear of said speed reducer , and a planet carrier rotationally coupled to said drive shaft , at least two planet gears being mounted in free rotation on said planet carrier and engaged between said sun gear and said annulus gear, - a base plate bearing said ring gear , said base plate being secured to said yoke of said electric motor , - the base plate comprising a plastic portion , which comprises abutment parts situated between the ring gear and the yoke , these abutment parts extending circumferentially around the ring gear , - said ring gear comprising tabs at its external periphery, damping pads being mounted between said tabs and said abutment parts , each damping pad having at least one rounded corner on a salient edge side of a corresponding tab of said ring gear , said rounded corner being rounded with a radius of curvature (R1) situated in a plane (P4) comprising all the corners of said damping pad , in such a way that there is space between said rounded corner and a right-angle corner defined by the intersection of planes (P1, P2) passing through lateral faces connected by this rounded corner , characterized in that the damping pad has a variable thickness at its ends, and in that the thickness of the damping pad follows a convex curvature in the form of a semicircle at its ends. - an electric motor comprising a yoke and a rotor mounted on a shaft , - a drive shaft able to be driven to rotate by said rotor , - a speed reducer of the epicyclic type mounted between the rotor shaft and said drive shaft , - said speed reducer comprising a ring gear forming an annulus gear of said speed reducer , a pinion rotationally coupled to said rotor shaft forming a sun gear of said speed reducer , and a planet carrier rotationally coupled to said drive shaft , at least two planet gears being mounted in free rotation on said planet carrier and engaged between said sun gear and said annulus gear, - a base plate bearing said ring gear , said base plate being secured to said yoke of said electric motor , - the base plate comprising a plastic portion , which comprises abutment parts situated between the ring gear and the yoke , these abutment parts extending circumferentially around the ring gear , - said ring gear comprising tabs at its external periphery, damping pads being mounted between said tabs and said abutment parts , each damping pad having at least one rounded corner on a salient edge side of a corresponding tab of said ring gear , said rounded corner being rounded with a radius of curvature (R1) situated in a plane (P4) comprising all the corners of said damping pad , in such a way that there is space between said rounded corner and a right-angle corner defined by the intersection of planes (P1, P2) passing through lateral faces connected by this rounded corner , <EOS>