I've put this out at least once before, but it bears repeating. Every highway tire legal for sale in the US is date-coded by the manufacturer. It looks something like this : DOT CC8M (ABC0714) The last 7 characters (in parentheses) will be recessed slightly in the sidewall, since the numbers in the tire mold are changed once a week. The first 3 letters identify the manufacturer, the first 2 numbers are the week (from 01 to 52), and the last 2 numbers are the year of manufacture. In the above example, the tire was made in the 7th week of 2014. Since trailer tires are not a high - volume item, it is not unusual to find 'brand new' tires that are a year or more old. Unlike fine wines, trailer tires do not improve with age. They sit without moving for weeks - or months - at a time, get underinflated or overinflated, dunked in saltwater, and attacked by UV and ozone. My personal preference on a single-axle trailer is load-range D radials, and I replace after 5 years. Maybe overcautious, but some years ago I was towing a 2100# boat, single axle, no brakes :nono:, with a 3500 # car :nono:, down the Vantage grade on I-90 at 65 MPH when I had a tread separation/blowout on a trailer tire. Haven't forgotten it, ever.... :hoboy:
Good advice! I wrote about a similar blowout experience a while back. Happened coming down route 93 here in N.H. Luckily I wasn't running too fast and managed to pull-over safely. I make it a habit to stay under 60 MPH with my trailers. BTW, if you've ever changed a tire on a highway with cars whizzing by, a few feet from your backside at 75 MPH, you'd think twice about keeping tires too long on your trailer. IMO, trailer tires are like batteries..........they have a relatively short life span, regardless of how they're treated. In the end, perhaps the best advice would be to buy the best radials you can afford, and (as davidsea suggests) change them every 5 years.
Yat