Trailer Tires and Wheels

Trailer tires usually age out before they wear out. Mounting and balancing runs about $12 to $25 per tire, plus the tire; a common ST205/75R15 Load Range D ran about $105 to $240 each by brand in retail listings. We read the date code on every tire, check pressure and sidewalls, mount and torque the wheels where the trailer sits, and tell you when to recheck the lugs.

Read the date code yourself

Federal rules (49 CFR 574.5) say every tire’s identification number ends in a four-digit date code: the first two digits are the week of the year, the last two the year. A tire stamped 2419 was made in the 24th week of 2019.

Trailer tire guidance attributed to Goodyear, Michelin, Carlisle and Maxxis says to replace trailer tires at five to six years regardless of tread. On a horse trailer that does a few hundred miles a year, the tread may look new on a tire that is past that age. That is why we read the date first.

Why trailer tires age fast here

Sunlight is one of the primary causes of rubber breaking down, and the small sidewall cracks called dry rot are age showing. A trailer parked in an open pasture or at the edge of a driveway takes sun on the same side of the tires for months. Tire covers slow that down on a trailer stored outside.

Common tire and wheel jobs

See the pricing page.

ST tires, load range and pressure

• ST means Special Trailer. Use ST tires on trailers, not passenger tires. ST tires are typically speed-rated for 65 mph.
• Load range. The tire’s load range has to carry the trailer. A Load Range D ST205/75R15 is listed at a 2,150 lb max load in retail listings.
• Pressure. Dexter’s tire wear chart reads like a pressure guide: both edges worn means under-inflation, center wear means over-inflation. Featherlite’s service chart says to check pressure when the tires are cold.

When tire wear is not a tire problem

Wear on one side of the tread, toe wear, cupping and flat spots point at the axle, the bearings or the brakes, not the tire. Dexter links side wear to loss of camber or overloading, toe wear to incorrect toe-in, cupping to imbalance and bearing adjustment, and flat spots to wheel lockup. Replacing the tire without fixing the cause just wears out the new one. See tires wearing on one edge, axle and suspension repair and trailer brake repair.

Lug nuts

Dexter’s manual says new wheels should have their nuts torqued at 10, 25 and 50 miles, and Featherlite adds after any impact and at the start of the towing season. A wheel that comes off at speed is one of the worst things that can happen on a trailer, and a torque wrench is the whole fix. We torque in sequence when we mount, and we write the recheck schedule on the invoice.

Rotation and spares

Featherlite’s service chart says to rotate trailer tires every 5,000 miles. Check the spare’s date code too: a spare that has ridden under the trailer for eight years is not much of a spare.