Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/873881
sets the limits of the tire," says Jamey Fish, director of market- ing, Michelin Earthmover NA. "We also use the miles traveled in one hour. These are limiting factors that have to be taken into account when trying to fi gure the correct limits of the tire and what the tire can be expected to do." 10-10-20 rule While TMPH is largely the concern of mining and quarry trucks, there is another rule of thumb that can help you avoid overloading tires on any type of equipment: the 10-10-20 rule that Caterpillar recom- mends on all its trucks. "What it means is no more than 10 percent of your loads should go above 10 percent of the rated load, and you should never exceed 20 percent of the rated load," says Johni Francis, Titan Tire's global OTR product manager. "I pres- ent that to all my customers whether they're using Caterpil- lar trucks or not." Other sources of heat Of course, speed, load and distance aren't the only vari- ables that can increase heat in a tire. These other factors can play a role in the longevity of any tire: • Incorrect air pressure. Un- der-inflation is bad for any tire. As the tire goes in and out of its footprint, under- inflation causes the rubber to flex more than it should, Pompo says. Most often, heat buildup is caused by under-inflation or overload- ing, Fish says. • Tread depth of the tire. Thick, heavy treads such as those used on an L5-type tire will be more susceptible to heat buildup. • Compounds used in making the tire. Cut-resistant com- pounds, because they're harder and thicker, also build up heat faster than rubber compound- ed for more traction. • The vehicle's mechanical condition. September 2017 | EquipmentWorld.com 30 maintenance | continued Low profi le tires with their reduced sidewall height give good stability and performance. Rubber compounds on earthmover tires must strike a balance between traction and wear.