A lawnmower height-of-cut adjustment mechanism 20 is disclosed. The adjustment mechanism 20 comprises an adjustment lever 30 mounted on the chassis and configured to rotate about a pivot point relative to the chassis, and front and rear linkages 50, 70 connected between the adjustment lever 30 and respective front and rear axle assemblies 60, 80. When the adjustment lever 30 is rotated about its pivot point, the front and rear linkages 50, 70 cause the axle assemblies 60, 80 to rotate and raise or lower the chassis relative to the wheels, the adjustment lever 30 thereby adjusting the height of the chassis relative to all four wheels simultaneously. A locking mechanism 40 is provided to hold the lever 30 in a desired position and maintain the position of the chassis relative to the wheels. The components of the adjustment mechanism lie in the same vertical plane. A spring 90 acts between the chassis and one of the axle assemblies or linkages, urging the axle assembly towards the raised position and providing a biasing force against the weight of the chassis.
