The invention refers to a mechanical design for a simple and accurate to assemble in-wheel electric motor comprising at least stator, rotor plate, rotor tube, bearing system and brake system arranged in such a way that rotor plate is attached to the rotor tube and to the bearing system and where the opening of the rotor tube and stator is on at least one axial side larger than the largest braking system or bearing system part. Brake system and bearing system parts and attachment points are accessible when rotor plate and outer parts of brake system, bearing system and the rim are removed. The rim is a separate part of the rotor plate and rotor tube. The rotor plate attachment to the bearing system is done in parallel to the rim attachment and is preventing loosening up. On at least one of the flanges there is an edge with its height smaller than the smallest radial cranny between the rotor tube and the stator.