Variable width wheel assembly

A wheel assembly comprising:

• a rim and a tire,
• wherein the rim has a variable width that enables a change in the volume of the tire, and
• wherein the tire comprises:
• a bead mounted so as to surround the rim;
• a side wall connected to the bead;
• a sub-tread formed on top of the side wall and made of a material having elasticity so as to have a curvature adapted to change in accordance with the change in the internal pressure of the tire;
• and
• plural tread blocks arranged on the sub-tread such that the distances between the tread blocks are adapted to change in accordance with the change in the curvature of the sub-tread, and wherein:
• the tire has a first diameter in an on-road mode in which the sub-tread has a planar shape, and has a second diameter that is larger than the first diameter in an off-road mode in which the sub-tread has a round shape having the curvature,
• the rim has a first width defining the on-road mode in which the distances between the plural tread blocks are minimized and a second width that is smaller than the first width and defines the off-road mode in which the distances between the plural tread blocks are maximized,
• the plural tread blocks have a hexagonal prism shape and one tread block is surrounded by six adjacent tread blocks,
• in the on-road mode, the one tread block is in contact with four tread blocks among the six adjacent tread blocks that surround the one tread block, and is separated at a predetermined distance from the other two tread blocks, and
• in the off-road mode, the one tread block is separated at a predetermined distance from all of the six adjacent tread blocks that surround the one tread block.