As mentioned, duals should be replaced in wheel pairs at a minimum - that is, both tires on the same corner of the truck should have the same loaded diameter. If not, the larger tire will carry a disproportionate share of the load, and the larger tire will skid the smaller tire (which wants to turn faster due to its smaller circumference) along, causing it to wear even faster.
2016 Ram Longhorn 3500 Dually 4x4 CCLB, 385/900 Cummins, Aisin AS69RC, 4.10
2014.5 DRV Mobile Suites 38RSSA #6972
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