OK...general tire info from someone that does PT work in a tire shop.....

BTW....I did a real long reply to this thread.....whatever reason it evaporated.......

Tires....age is a killer.

On pretty much ANY tire is a mold date. Shop should NOT sell as new beyond 3 years from mold date.
Period.
At least in the US (likely other locations), should be a molded oval about 1"X1/2"...,,(metric.....figure it out....inches landed on the moon...nuff said.....yes, biased....).
There should be a 4 digit number......first 2 is week of the year .....0-52, last 2 is last 2 of year........
So.....a "4217" is......42'nd week of the year 2017.

"Thou shall not sell as new beyond 3 years from mold date".
Period. I believe US law.
Prime reason, from decades of dealing with tires,.....age....usually UV aging added to low pressure. Ramy does a lot of travel....so he is on the good side. He checks pressures, does miles, a perfect tire/I'm loses some pressure over time....not counting the "rule of thumb" that tire pressure changes about 1 PSI/*F change in temp. Metric guys.....figure it out...
Sitting on low/flat tires does NOT help.
Old tires lose their flexing, thus overheat and tread thrown.

Yes, US is usually longer trips at higher speeds.
No slight on other regions.

I see more blown tires from trailers sitting for years, likely low in pressure, then subjected to high highway speeds with aged tires.

Discuss......