Most mower tires are made from a hard plastic rather than rubber and an inner tube like car tires. Push mowers most notably have plastic tires because of the flat terrain they normally mow. When these plastic tires become worn or damaged, the quality of the cut declines, simply because the mower will sit uneven. Replacing worn-out tires will provide a more uniform cut to the lawn and more ease when pushing.
Remove the sparkplug wire from the sparkplug. Wedge a block of wood through the grass discharge against the blade to hold it in place and prevent it from turning during the tire change.
Tilt the mower on its side, placing a block of wood under the mower deck. Rest the mower onto the block of wood, suspending the tire in the air.
Grip the plastic cap in the center of the tire firmly with pliers. Twist and pull the cap from the tire, exposing the nut underneath. Remove the nut, turning counterclockwise. Slide the damaged tire off the spindle or drive shaft.
Place a new tire onto the drive shaft. Replace the nut over the spindle and turn clockwise with a wrench to tighten. Push the plastic cap over the nut until it snaps into place.
Remove the wood block from the grass discharge and under the mower deck. Lower the mower onto its wheels. Reattach the sparkplug wire to the sparkplug.