Patent ID: 8863865

Claim:
A ground engaged vehicle comprising: a front portion, a rear portion, said front and rear portion being joined by an articulation, said articulation rotating around a longitudinal axis of said vehicle; a hydrostatic drive system driving each of four wheels; at least two wheels being mounted on one of said front portion or said rear portion and at least one other wheel being mounted on the other of said front portion or said rear portion; each of said wheels being mounted on a hydrostatic motor and each of said hydrostatic motors being fixedly mounted on a rotating, substantially vertical axis; said hydrostatic drive system having a high gear and a low gear; said wheels having an operational internal tire pressure of at or below about 10 psi and each of said wheels being mounted without suspension; whereby said articulation and said low pressure tires providing shock absorption and substantially continuous ground contact for each of said wheels in both said high and low gear; and a valve assembly, said valve assembly having two intake ports and four output ports, said valve assembly having a first position and a second position, said first position directing hydrostatic fluid out of a first pair of output ports and said second position driving a hydrostatic fluid out of a second pair of output ports.