Generally speaking, crane wheels mainly refer to casting cranes, bin feeding cranes, slab handling cranes, steel coil clamp cranes, disk cranes and other bridge cranes that serve higher-level work in metallurgical plants. In order to ensure the safe operation of the crane, clear accuracy requirements are put forward for the diameter of the traveling wheel during the design of the crane, and the diameter tolerance of the traveling wheel is specified to be h9. The relative difference in diameter of a corresponding set of driving wheels running on two far apart rails plays a decisive role in the safe operation of the crane. When two corresponding sets of traveling wheels run on tracks in each direction, the running distances per unit time are different, which will cause the crane to run out of sync and affect the safe operation of the crane. Therefore, it is very important to pair the traveling wheels on the crane to control the relative diameter difference of the traveling wheels. The relative diameter difference of the same set of wheels should generally be controlled within 0.12-0.15mm.