The Work Capability Factor (WCF) formula for load-and-carry dozers and loaders is figured by multiplying the average ton load per tire and the maximum average speed of the machine per hour.First, determine the average tire load for each tire by adding the empty tire load to the load and dividing by 2. For example:12.9 tons empty + 21.7 tons loaded ÷ 2 = 17.3 tons avg. loadThen determine the maximum average machine speed: To find this figure, compute the roundtrip distance in miles and multiply that number by the maximum number of cycles (roundtrips) per hour of continuous load-and-carry operations. (Short periods of vehicle downtime should not be included in the average speed calculation due to the relatively slow static cooling rate of dozer and loader tires.)As an example, assume a cycle of 800 ft. (400 ft. each way):800 ft. ÷ 5280 ft./mi. = 0.152 mi./cycle
0.152 mi. x 30 cycles = 4.6 mphNow you have both the average tire load for this job and the maximum average tire speed. Use them to calculate the WCF rating your tires should have for this load:17.3 tons x 4.6 mph = 79.58 WCFBy checking your Goodyear tire WCF ratings, you select the tire with an 80 WCF.If you want to check the usability of the tires already on your machine, just reverse the process. By dividing the WCF tire rating by the average load (e.g., 80 ¸ 17.3), you can derive the maximum speed (or number of cycles) that your machine can safely perform using those tires. As an example, if the calculation shows that the maximum speed should be 3.6 mph, you can recalculate the maximum number of cycles that will result in a 3.6-mph speed:3.6 mph x 5280 ft./min. ÷ 800 ft./cycle
= 24 cycles/hour maximum
0.152 mi. x 30 cycles = 4.6 mphNow you have both the average tire load for this job and the maximum average tire speed. Use them to calculate the WCF rating your tires should have for this load:17.3 tons x 4.6 mph = 79.58 WCFBy checking your Goodyear tire WCF ratings, you select the tire with an 80 WCF.If you want to check the usability of the tires already on your machine, just reverse the process. By dividing the WCF tire rating by the average load (e.g., 80 ¸ 17.3), you can derive the maximum speed (or number of cycles) that your machine can safely perform using those tires. As an example, if the calculation shows that the maximum speed should be 3.6 mph, you can recalculate the maximum number of cycles that will result in a 3.6-mph speed:3.6 mph x 5280 ft./min. ÷ 800 ft./cycle
= 24 cycles/hour maximum
