ServiceNomad RV · Knowledge
RV Tire Cupping or Uneven Wear
Unusual tire wear patterns on your RV—such as cupping (scalloped high and low spots around the tread), feathering (tread blocks worn at an angle), or rapid wear on one side—indicate underlying mechanical problems with alignment, suspension, or tire pressure. Ignoring these patterns leads to premature tire failure, poor handling, and potential blowouts at highway speeds. Understanding what different wear patterns reveal helps you address the root cause before it becomes a safety hazard.
Cupping and Scalloped Wear
Cupping appears as a series of high and low spots around the tire circumference, creating a wavy or scalloped appearance. It's most often caused by worn or damaged suspension components—particularly shock absorbers or struts. When suspension can't properly dampen wheel bounce, the tire repeatedly pounds into the pavement, wearing high spots at each impact point. Cupped tires produce a distinctive thumping or rumbling sound that increases with speed. If you notice rhythmic noise from your tires or feel vibration through the steering wheel or floor, inspect the tires for cupping. Replacement shocks or suspension repair is necessary to prevent the pattern from recurring on new tires.
One-Sided Wear and Alignment Issues
If the inner or outer edge of a tire is worn significantly more than the rest of the tread, the RV has an alignment problem—specifically, excessive toe-in, toe-out, camber, or caster. RV alignments are more complex than passenger cars due to weight distribution, dual rear axles (on many motorhomes), and the stresses of towing. Misalignment causes the tire to scrub sideways as it rolls, rapidly wearing one edge. Alignment issues can result from hitting potholes, curbs, or road debris, or from worn suspension bushings and ball joints that allow components to shift out of specification. A specialized RV alignment shop with heavy-duty equipment is necessary—many passenger car alignment shops cannot accommodate RVs or properly align dual-axle setups.
Feathering and Toe Angle
Feathering is when tread blocks are worn smooth on one edge and sharp on the other, resembling a row of ramps. This is almost always caused by incorrect toe angle (the direction the wheels point relative to the RV centerline). Excessive toe-in or toe-out causes the tire to scrub as it rolls, creating the feathered pattern. You can feel feathering by running your hand across the tread—one direction will feel smooth, the other will catch on the sharp edges. Correcting toe angle through alignment will stop the progression, but feathering that has already occurred is permanent until the tire wears enough to smooth out or is replaced.
Center or Edge Wear from Inflation
Tires worn primarily in the center indicate chronic overinflation—the tire is too firm, and only the center tread contacts the road. Tires worn on both outer edges indicate chronic underinflation—the sidewalls flex excessively, and the edges carry all the load. Both conditions reduce tire life, increase rolling resistance, and raise the risk of sudden failure. RV tires must be inflated to the pressure specified by the RV manufacturer based on actual axle weights, not the maximum PSI shown on the tire sidewall. Weigh your RV when loaded for travel, then consult tire inflation charts from the tire manufacturer to determine the correct pressure for each axle. Check tire pressure when cold (before driving) at least monthly.
⚠️ Safety Notes
- Tires with severe uneven wear are structurally compromised and more prone to blowouts—replace them before extended highway driving.
- Cupping and feathering can indicate dangerous suspension failures—have the RV inspected by a qualified technician immediately.
💡 Prevention Tips
- Weigh your RV fully loaded and inflate tires to the correct pressure for your actual axle weights—this is the single most important tire maintenance task.
- Inspect tires for unusual wear patterns every few months and address alignment or suspension issues promptly.
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