Localized dished out areas of fast wear creating a scalloped appearance around tire. Appears around the tire on the shoulder ribs. May progress to adjoining ribs.
Any loose or worn component in truck steering or suspension systems can cause odd wear, cupping, and flat spots.
Usually a result of moderate to severe assembly out of balance condition, improper rim/wheel mounting or other assembly non-uniformity. Can also be due to lack of shock absorber control on some suspension types.
Check for loose wheel bearings, worn shock absorbers, steering gear lash, worn tie rod ends, and kingpins. Check for possible mismount conditions. If ride complaints arise, tires may be rotated to drive axle. Diagnose imbalance condition, i.e., wheel, rim, hub, brake drum. Correct as necessary.