Trailer tires are their own category: look for the ST marking on the sidewall, because those tires are built for load and not for steering or grip. Detroit Tire Shop in Detroit, MI can help match a replacement to your trailer's load rating. Call with the size and the axle's rated capacity.
A trailer tire fails differently from a car tire. It sits for weeks, then runs loaded at highway speed, and the sidewall pays for both. Most trailer blowouts trace back to rot, underinflation, or a tire that was never rated for the weight in the first place, not to a nail.
Start at the sidewall. A tire marked ST is designed for trailer duty. Passenger and light-truck tires are built for different loads and different forces, so ask before substituting one for another.
How do I read a trailer tire to pick the right replacement?
Find the size, the ST marking, and the load rating on the sidewall, then compare the rating against the trailer's axle capacity listed on its data plate. Each tire has to carry its share, with margin to spare. If the rating on the tire is lower than what the axle can carry, the tire is the weak point.
Check whether the trailer has a spare mounted. Many owners find out at the roadside that it is rotted or flat.
Why do trailer tires go bad when they barely get used?
Rubber cracks from age and sunlight. A tire that looks fine on top can show fine cracks in the sidewall or between the tread blocks, and that cracking is the signal to replace, whatever the tread says.
Underinflation does the rest. A trailer that sits through a cold stretch loses pressure, and the first loaded trip heats the sidewall. Check pressure cold, before you hook up.
Do both tires on an axle need to match?
Yes. Replace in pairs per axle at minimum, and keep sizes and brands the same on an axle, so each tire carries its share. Ask the shop to look at the wheel and hub condition while the tires are off, since a bent rim or a bad bearing will ruin the new tire.
Can I use car tires on my trailer?
Not as a like-for-like swap. Trailer tires are designed for load, and a passenger tire may not carry the same rating. Match the load rating on the data plate and ask the shop if you are unsure.
How do I know a trailer tire is too old?
Look for cracks in the sidewall and between the tread blocks, regardless of how much tread is left. Check the date code on the sidewall too.
Which Detroit shop should I call?
Detroit Tire Shop at 13054 Grand River Ave can answer size and availability questions. Call before you drive over with the trailer.