Loosening of the wheel bolts may be the cause of accidents where the wheel falls off while the trailer is running. When the transverse force of wheel bolts exceeds a certain proportion of the bolt shaft force, the wheel nut begins to loosen. Loosening of a wheel bolt may influence on the deformation of wheel and the transverse forces of other wheel bolts increase, and the bolts may also loosen. In this report the 3-dimensional deformation of the disk wheels and the transverse forces on the wheel bolt are determined by 3-dimensional numerical analysis. In the result, by loosening of 1 bolt the transverse forces at lower position of wheel increase and the concentration at the upper position of wheel cancel.
