How Long Do Travel Trailer Tires Last?

This surprises people who come to trailers from cars, where tires wear out. A trailer tire with 80% of its tread left can be dangerously old, and it will look fine right up until it comes apart.

Why age rather than miles

A typical travel trailer covers a few thousand miles a year. The rest of the time it sits — in a driveway, a storage lot, or a seasonal site — with the tires exposed to sunlight.

Two processes work on the rubber. UV breaks down the polymer chains at the surface, which is what produces the fine cracking you see on an old sidewall. Ozone attacks the rubber chemically, which does the same thing from a different direction. Both act on the sidewall, which is the part doing structural work and the part that fails.

Tread depth measures abrasion, which is a function of miles. It tells you almost nothing about the condition of the sidewall, which is a function of years.

Reading the date code

Find the DOT code molded into the sidewall. It is a long alphanumeric string, and the last four digits are the week and year of manufacture.

Two practical notes. The code may be on only one side of the tire, so check both. And check the date on tires you are buying, not just on the ones you are replacing — a tire that has sat in a warehouse for two years has already used two years of its life.

What shortens tire life

Sunlight. The dominant factor. A trailer parked south-facing in Arizona ages tires far faster than one in a covered storage unit.

Underinflation. Sidewall flex generates heat, and heat accelerates the chemical degradation. Running 15 psi low on hot interstates is how a three-year tire fails at two. The psi guide.

Overloading. Running near or past the tire’s rated capacity, which is what happens when somebody fitted a lower load range than the placard specifies.

Sitting still, in one position. A tire supporting weight in one spot for months takes a flat spot and the sidewall is under constant local stress. Moving the trailer occasionally helps, and taking weight off the tires for long-term storage helps more.

Heat and speed. Heat build-up rises sharply with speed, and the sidewall speed symbol is a limit.

What extends it

• Covers. The cheapest and most effective single measure, because it addresses UV directly. Four covers cost less than one tire.
• Correct pressure, cold, every trip. Free.
• Correct load range. Match the placard when you replace.
• Moving it occasionally. Even a few feet changes the loaded spot.
• Shade. Where you have the option, park out of direct sun.

What does not help, despite being widely sold: tire dressings and protectants. Many contain petroleum distillates that leach the anti-ozonant compounds out of the rubber, which accelerates exactly what you were trying to prevent. If you use anything, use a water-based product, and mostly just use covers.

What to check, twice a season

Date codes, so you know where you are in the window.

Sidewall cracking. Fine surface crazing is age showing. Cracks deep enough to catch a fingernail in are a tire to replace now regardless of date.

Uneven wear. Wear concentrated on one edge points at an axle or alignment problem rather than a tire problem. What inside-edge wear means.

Bulges. A bulge in the sidewall is internal structural damage, usually from a curb or a pothole impact. Replace immediately; this one does not wait.