Assembly for mounting a wheel to a portal gear box of an off-road vehicle

A vibration-reducing portal box assembly for mounting a wheel of an off-road vehicle, comprising:

• a) a box housing having a receptacle adapted to receive a stock axle shaft of the off-road vehicle;
• b) an output shaft operably connectable to the stock axle shaft received in said housing and effective to rotate upon rotation of said stock axle shaft;
• and
• c) a wheel hub having a central opening adapted to receive said output shaft, and adapted to turn a wheel mounted to said wheel hub upon rotation of said output shaft;
• wherein said output shaft has a proximal end portion having a first diameter, a distal end portion having a second, reduced, diameter, and a tapered portion connecting the proximal end portion to the distal end portion;
• wherein the central opening of said wheel hub has a proximal end portion having a first diameter, and a distal end portion having a second, reduced, diameter, and a tapered portion therebetween to matingly receive the tapered portion of the output shaft;
• wherein in the area where the diameter of the output shaft and the diameter of the wheel hub are reduced, the wheel hub supports the output shaft.