Construction of a car wheel. The car wheel consists of a hub, shield (or spokes), rims and tires. The hub of the non-driving wheel is mounted by means of rolling bearings on the stub axle or the bearing axle stub and fixed on it with a nut. The wheel hub is equipped with several bolts for attaching the disc to the rim. The drive wheel hub is put on the drive shaft journal, on which can (be positioned with a wedge or bolted permanently to the drive shaft flange (usually on trucks) or to a cap slidably mounted on the splined end of the driveshaft. In large trucks, due to the heavy load, twin driving wheels are used, composed of one hub and two discs with rims attached to it. Wheel center with rim. The wheel center of the car is pressed from steel plate with a rim that is welded or riveted, on which the tires are put on. The wheel disc is attached to the hub with a few bolts. The holes for the bolts in the disc have corresponding tapered or circular bores, and the base of the bolt nuts are conical or hemispherical in shape. The generated friction protects the nuts against self-unscrewing. A brake drum is attached to the wheel disc.