Tires: Tire Lifetime Expectancy, words of caution, tire companies

Question
Hello,

My tires were installed five years ago. They were probably one to two years old at time of installation.

Currently the tread is OK as I put around  four or five thousand miles per year on my car. However, the space between the treads shows mini cracks.

My first question is: how often should tires be replaced due to age ?

My second question is: current tires are Michelin but someone said that Toyo is a better grade tire. Is there someone that grades tire
companies ?

I know about Uniform Tire Grading System. However, this can be misleading to me.

Thank you for your time and consideration.

rayed85@nevada.co.jp

Answer
Ray,

I am currently recommending that tires be replaced when they reach 10 years of age.

However, if you live in the following states the figure is 6 years of age - CA, AZ, NM, NV, TX, FL.  It's a temperature dependent thing, so other states are proportional between 6 and 10 years.  Example TN would be 8.

If you know about UTQG, then this shouldn't be misleading.  It's just one more tool to help make a decision.

There are several web sites where tires are rated by the folks that bought them.  just surf around and you'll find them. 2 words of caution - These ratings are by untrained people and the ratings aren't compensated by the product's cost.

Hope this helps.