Bolt on suspension kit for increasing vehicle payload

A vehicle suspension system comprising:

• a first suspension assembly operably coupling a first wheel to a chassis of a vehicle;
• a second suspension assembly operably coupling a second wheel to the chassis, the first and second wheels forming a pair of front wheels;
• a third suspension assembly operably coupling a third wheel to the chassis;
• a fourth suspension assembly operably coupling a fourth wheel to the chassis, the third and fourth wheels forming a first pair of rear wheels;
• and
• a payload extension kit that is attachable to the chassis non-permanently,
• wherein the payload extension kit includes a fifth suspension assembly operably coupling a fifth wheel to a sub-frame extension of the payload extension kit, and a sixth suspension assembly operably coupling a sixth wheel to the sub-frame extension, the fifth and sixth wheels forming a second pair of rear wheels,
• wherein the third and fourth suspension assemblies include a first leaf spring assembly and a second leaf spring assembly, respectively, and
• wherein the fifth and sixth suspension assemblies include a third leaf spring assembly and a fourth leaf spring assembly, respectively,
• wherein the first and second leaf spring assemblies support a master axle at a middle portion of each of the first and second leaf spring assemblies, and
• wherein the third and fourth leaf spring assemblies are operably coupled to the master axle at a first end thereof, and operably coupled to a slave axle at a second end thereof.

A payload extension kit that operably couples to a chassis of a vehicle having a front pair of wheels and a first rear pair of wheels to increase a payload capacity of the vehicle, the payload extension kit comprising:

• a sub-frame extension;
• a pair of suspension assemblies operably coupling a second pair of rear wheels to the sub-frame extension,
• wherein the chassis comprises a first longitudinal frame member, a second longitudinal frame member, and a transverse frame member extending between the first and second longitudinal frame members,
• wherein the sub-frame extension comprises a first longitudinal sub-frame member, a second longitudinal sub-frame member, and a transverse sub-frame member extending between the first and second longitudinal sub-frame members,
• wherein the first longitudinal sub-frame member is non-permanently fixed to the first longitudinal frame member, and the second longitudinal sub-frame member is non-permanently fixed to the second longitudinal frame member via a removable fixing member,
• wherein the first and second longitudinal frame members each include a first bracket on a lateral side thereof,
• wherein the first and second longitudinal sub-frame members each include a second bracket corresponding to the first bracket, and
• wherein the first and second brackets are affixed to each other via a vertical fixing member.