Trailer tires fail from age before they fail from tread wear — a trailer parked between hauls develops sidewall cracking long before the tread looks worn, and that's what lets go on the highway under a loaded trailer. San Diego Tire Shop checks trailer tires by age and sidewall condition, not just tread depth, at 6215 University Ave.
Most trailer tires never wear out. They dry-rot first, sitting in a driveway or storage lot for months between trips while the sidewall rubber breaks down from sun and ozone exposure — and a tire with plenty of tread left can still blow out on the freeway because the rubber underneath has already gone brittle. That's the failure mode that catches people off guard, since the check everyone knows to make — tread depth — doesn't catch it.
San Diego Tire Shop checks trailer tires for sidewall cracking and reads the DOT date code before a trip, not just the tread, and stocks ST-rated trailer tires sized for utility trailers, boat trailers, and small campers at 6215 University Ave B STE B, serving trailers hauled in from any of its 13 service areas.
Why do trailer tires need a different tire than the truck pulling them?
A trailer tire is built with a stiffer sidewall than a passenger tire because it's carrying weight without steering or driving the vehicle — that's what an ST rating means. Fitting a passenger or light-truck tire onto a trailer axle because it happened to be the right size is a common shortcut, and it's also why some trailer tires fail well before the load rating would suggest they should.
When does a trailer tire actually need to be checked?
Before a trip, not after one. A trailer that only comes out a few times a year is exactly the kind that develops sidewall cracks nobody looks for, since there's no daily driving to reveal a problem early. Checking sidewall condition and tire age before hooking up — not just glancing at tread — is what catches a tire about to fail under load instead of finding out on the shoulder of the freeway. Calling (858) 988-6336 ahead of a trip is enough to get it looked at without an appointment.
My trailer tires still have good tread — do they still need to be checked?
Yes. Tread depth is the wrong test for a tire that mostly sits parked, since sidewall rubber degrades from age and sun exposure regardless of how much tread is left. A tire with deep tread and a cracked sidewall is more likely to fail than one with shallower tread and a sound sidewall.
What's an ST-rated tire, and does my trailer need one?
ST stands for special trailer, and it means the sidewall is built stiffer than a passenger tire's to carry a load without steering or powering the trailer itself. Most utility, boat, and small camper trailers are built around that spec, and swapping in a passenger tire because it's the same size skips the reason the ST rating exists.
How old is too old for a trailer tire?
There's no tread number that answers that, since trailer tires age out from the inside before the tread tells you anything. San Diego Tire Shop reads the DOT date code stamped in the sidewall as part of a pre-trip check, which is the only real way to know.