Tires

I am not 100% certain what you are asking with your first question but, I will assume you mean what kind of rotation pattern should be used. If that is the case, my answer is to move the tires from the forward axle to the rearward axle (and visa versa) and to reverse the direction of rotation. Although many fleets do not do this with their drive tires, it does even out the wear between the two drive axles and cleans up any irregular wear that may have begun. Regarding the second question, that is nearly impossible to answer unless I know the type of service the truck is running. Waste pick-up vehicles get a lot fewer miles out of their drive tires than a line haul tractor.