Itís important to check the age of your horse trailer tires because the rubber degrades over time. Iíve never really thought about it but it does seem to make sense. I called my trailer gurus and both said that tire manufacturers are recommending that any tire be replaced if itís over 6 years old. And old doesnít mean from when the tire was placed on the trailer. Itís from the date of manufacture.
The code with the manufacturing date information is printed on the tires and is a bit cryptic but once you learn the code itís easy peezy to figure out. Basically itís a two digit week of year and two digit year.
You can learn more on reading the code and see examples here