A grain cart is provide having a wheel assembly with four ground wheels that all pivot in unison. The wheel assembly can include a first side front wheel, a first side rear wheel, a second side front wheel and a second side rear wheel. A first side steering link assembly can be operatively coupled between the first side front wheel and the first side rear wheel to cause the first side front wheel and the second side rear wheel to pivot in opposite directions. A second side steering link can be operatively coupled between the second side front wheel and the second side rear wheel to cause the second side front wheel and the second side rear wheel to pivot in opposite directions. A unison linkage assembly operatively can couple the movement of the first side rear wheel and second side rear wheel.
