The running surfaces of the wheels become worn during operation. This reduces the diameter of the wheels.

This section shows how to check the diameter on a non-driven wheel. The check of the diameter on a powered wheel does not differ significantly.

   Measure the diameter of the wheel at multiple points over the width of the wheel.

   The diameter may not be smaller than is specified in the table.

If the diameter is smaller, the wheel must be replaced. See Disassembling the wheel.