Abstract: Pivoted 180.degree. apart on the periphery of a sprinkler wheel, a pair of arms can be swung from folded position within the compass of the wheel to unfolded or operative position whenever it is necessary to immobilize the wheel. The distal end of the arms carries a foot plate with spikes, enabling the operator to force the spikes into the ground with foot pressure. In the operative position, the arm pivots are located on a horizontal diameter of the wheel and the arms are inclined downwardly at an angle of 45.degree. for effective holding effort.