Wheel assembly for an irrigation system

A method of assembling first and second wheel assemblies of a support tower of a movable irrigation system, the method comprising:

• mounting a first central support having a plurality of outwardly protruding spokes and a first rotational reference point onto a first central hub;
• mounting a second central support having a plurality of outwardly protruding spokes and a second rotational reference point onto a second central hub spaced from the first central hub so that the second central support is spaced from the first central support and aligned with the first central support along a path for traversing;
• measuring a distance between the rotational reference points to determine a relative rotational alignment of the second central support;
• and
• adjusting the first central support or the second central support until the distance between the rotational reference points is equal to a predetermined distance.

A support tower for a movable irrigation system for traversing a path along a ground surface having a layer of soil, the support tower including first and second wheel assemblies collectively comprising:

• a leading wheel and a trailing wheel aligned with and spaced from each other along the path, each wheel having a plurality of outwardly protruding spokes defining a plurality of recesses therebetween, each wheel including a reference point for rotationally synchronizing the wheels;
• and
• an airless flexible tire mounted on each wheel and having a plurality of rigid sections each including an inwardly facing mounting boss for aligning with and engaging the outwardly protruding spokes, and a plurality of flexible sections for aligning with the recesses, the outwardly protruding spokes being configured to urge the rigid sections into the layer of soil when the rigid sections contact the ground surface and wherein the recesses between the outwardly protruding spokes permit the flexible sections to flex inwardly towards the recesses when the flexible sections contact the ground surface so that the rigid sections and the flexible sections cooperatively form a corrugated pattern in the ground surface without urging the soil to side margins of the airless flexible covering, the corrugated pattern having a plurality of valleys formed by the rigid sections and a plurality of spaced peaks formed by the flexible sections, and the airless flexible tires each having a plurality of outwardly facing traction lugs for improving traction.