12. OPERATION 12.18 HANDLING THE TIRES 12.18.1 PRECAUTIONS WHEN HANDLING TIRES CAUTION If a tire has reached any of the following service limits, there is danger that the tire may burst or cause an accident, so to ensure safety, replace it with a new tire. Service limits for wear fiWhen the remaining depth of the groove on construction equipment tires (at a point approx. 1/4 of the tread width) is 15% of the groove depth on a new tire. fiWhen the tire shows marked uneven wear, stepped wear or other abnormal wear, or when the cord layer is exposed.
Service limits for damage fiWhen there is external damage extending to the cord or when the cord is broken fiWhen the cord is cut or there is dragging fiWhen the tire is peeling (there is separation) fiWhen the bead is damaged fiFor tubeless tires, when there is air leakage or improper repair Please contact your Komatsu distributor when replacing the tires. It is dangerous to jack up the machine without taking due care. 12.18.2 TIRE PRESSURE Measure the tire pressure before starting operations, when the tires are cool. If the tire inflation pressure is too low, there will be overload; if it is too high, it will cause tire cuts and shock burst.
To prevent these problems, adjust the tire inflation pressure according to the table on the next page. Deflection ratio = H – h x 100 H As a guideline that can be checked visibly, the deflection ratio of the front tire (deflection/free height) is as follows. When carrying normal load (lift arm horizontal): Approx. 10 – 15% When digging (rear wheels off ground): Approx. 20 – 25% When checking the tire inflation pressure, check also for small scratches or peeling of the tire, for nails or pieces of metal which may cause punctures, and for any abnormal wear. Clearing fallen stones and rocks from the operating area and maintaining the surface will extend the tire life and give improved economy.
For operations on normal road surfaces, rock digging operations: ....................................... High end of range in air pressure chart Stockpile operations on soft ground: ....................................... Average pressure in air pressure chart Operations on sand (operations not using much digging force) ....................................... Low end of range in air pressure chart 2-71