A vehicle comprising: a frame; two wheels (3, 4) mounted at or towards a rear end of the frame; a steered wheel centrally mounted at or towards a front end of the frame; two stabiliser wheels (9, 10) mounted at or towards the front end of the frame to respective sides of the steered wheel; and a suspension mechanism between the frame and the steered wheel to permit vertical travel of the steered wheel relative to the frame, the suspension mechanism comprising biasing means for the steered wheel, the biasing means acting directly or indirectly between the frame and the steered wheel to urge the steered wheel downwards relative to the frame, wherein the biasing means is arranged and selected such that in use, when the vehicle is on an uneven surface, where the stabiliser wheels (9, 10) come into contact with the ground so that the frame is supported at least partially by the stabiliser wheels (9, 10), the biasing means urges the steered wheel downwards into contact with the surface to act to maintain the steered wheel in contact with the surface, to retain steerage as the vehicle becomes partially supported by the stabiliser wheels (9, 10), the vehicle being characterised in that the suspension mechanism further comprises a suspension stop arranged to limit upward travel of the steered wheel against the biasing means relative to the frame, wherein the biasing means is arranged to be adjusted for the weight of a given rider to control the downward force applied by the biasing means on the steered wheel such that in normal use, when the vehicle is on a flat level surface, the weight of the vehicle and weight of a rider urge the frame downwards relative to the steered wheel, against the biasing means, until the suspension stop limits further downward travel of the frame relative to the steered wheel, where the front of the frame is then supported by the steered wheel and the suspension stop, with the suspension stop retaining the front of the frame at a height above the surface such that there is a clearance between the stabiliser wheels (9, 10) and the flat level surface. a frame; two wheels (3, 4) mounted at or towards a rear end of the frame; a steered wheel centrally mounted at or towards a front end of the frame; two stabiliser wheels (9, 10) mounted at or towards the front end of the frame to respective sides of the steered wheel; and a suspension mechanism between the frame and the steered wheel to permit vertical travel of the steered wheel relative to the frame, the suspension mechanism comprising biasing means for the steered wheel, the biasing means acting directly or indirectly between the frame and the steered wheel to urge the steered wheel downwards relative to the frame, wherein the biasing means is arranged and selected such that in use, when the vehicle is on an uneven surface, where the stabiliser wheels (9, 10) come into contact with the ground so that the frame is supported at least partially by the stabiliser wheels (9, 10), the biasing means urges the steered wheel downwards into contact with the surface to act to maintain the steered wheel in contact with the surface, to retain steerage as the vehicle becomes partially supported by the stabiliser wheels (9, 10), the vehicle being characterised in that the suspension mechanism further comprises a suspension stop arranged to limit upward travel of the steered wheel against the biasing means relative to the frame, wherein the biasing means is arranged to be adjusted for the weight of a given rider to control the downward force applied by the biasing means on the steered wheel such that in normal use, when the vehicle is on a flat level surface, the weight of the vehicle and weight of a rider urge the frame downwards relative to the steered wheel, against the biasing means, until the suspension stop limits further downward travel of the frame relative to the steered wheel, where the front of the frame is then supported by the steered wheel and the suspension stop, with the suspension stop retaining the front of the frame at a height above the surface such that there is a clearance between the stabiliser wheels (9, 10) and the flat level surface.