Like most things, the truth usually lies somewhere in the middle. There are too many variables to put a definite number of years on tire life and tire shops have a definite interest in giving you a worst case number. Around here they have been lobbying government to impose end of life laws for car tires
- they want police to ticket if you have a car with tires
more than 5 years old. Awfully good for tire shops but not very good for a senior with 15k on their garage kept Buick whose tires
should easily last 10 years or more.
Heat is the main enemy of tires and a high quality tire will be damaged in minutes due to overloading or under inflation and may still run many miles or years before it fails outright. If you donít know the history of your tires, be extra cautious.
A tire not abused or subject to excessive sun or heat should last 10 years minimum but initial quality plays into that also and is pretty hard to determine externally. Once tires develop cracks extending beyond the surface they allow sand and grit to enter which accelerates the wear and will damage the cords. Usually tires separate rather than blow out though most people donít notice the separation and continue driving until they do blow out.
Inspect your tires carefully and replace when there are signs of damage. You canít hear or feel a trailer tire beginning to fail like you can on your tow vehicle. Your only indication of condition is temperature. Get an infrared thermometer and keep track of temperature keeping in mind sun and road temps. Tires follow a temperature pattern and when one starts to vary from the pattern there is an issue to investigate.