A set of two identical powertrain modules, a first powertrain module and a second powertrain module of the set of two identical powertrain modules each comprising: - a powertrain system for driving at least one wheel of a vehicle, the powertrain system comprising: - a motor having an output shaft; - and a transmission system between the motor and a drive shaft connected to said wheel, the transmission system having a first axis associated with the motor output shaft and a second axis configured to be associated to the drive shaft, the axes (A100, A200) preferably being parallel; - and a casing which houses the transmission system, the casing including a receiving area configured to mount a gear system about a third axis parallel to the first axis and the second axis, the gear system being configured to be connected to an output shaft of an additional motor and to mesh with a part of the transmission system; characterized in that said powertrain modules are arranged in a facing relationship so that the second axes of the transmission systems of said powertrain modules are substantially coincident, and the casings of said powertrain modules are rotationally offset the one relative to the other around said second axes, wherein each powertrain module of the set further comprises connecting means, the connecting means of the powertrain modules of the set cooperating with each other for mechanically connecting said two powertrain modules, and a plane including the first axis and the second axis and a plane including the second axis and the third axis form an angle (α), the casing includes a first leg and a second leg defining the angle (α), and the first powertrain module is configured to receive the motor (5, 5') of the second powertrain module between the first leg and the second leg of the casing of the first powertrain module. - a powertrain system for driving at least one wheel of a vehicle, the powertrain system comprising: - a motor having an output shaft; - and a transmission system between the motor and a drive shaft connected to said wheel, the transmission system having a first axis associated with the motor output shaft and a second axis configured to be associated to the drive shaft, the axes (A100, A200) preferably being parallel; - a motor having an output shaft; - and a transmission system between the motor and a drive shaft connected to said wheel, the transmission system having a first axis associated with the motor output shaft and a second axis configured to be associated to the drive shaft, the axes (A100, A200) preferably being parallel; - and a casing which houses the transmission system, the casing including a receiving area configured to mount a gear system about a third axis parallel to the first axis and the second axis, the gear system being configured to be connected to an output shaft of an additional motor and to mesh with a part of the transmission system; characterized in that said powertrain modules are arranged in a facing relationship so that the second axes of the transmission systems of said powertrain modules are substantially coincident, and the casings of said powertrain modules are rotationally offset the one relative to the other around said second axes, wherein each powertrain module of the set further comprises connecting means, the connecting means of the powertrain modules of the set cooperating with each other for mechanically connecting said two powertrain modules, and a plane including the first axis and the second axis and a plane including the second axis and the third axis form an angle (α), the casing includes a first leg and a second leg defining the angle (α), and the first powertrain module is configured to receive the motor (5, 5') of the second powertrain module between the first leg and the second leg of the casing of the first powertrain module.