I have a chance to buy 4 new Michelin Latitude Diamaris 255/50/20 tires for $287 US Dollars each and free shipping. The manufacture date is 06/2009 but the have been in a temperature controlled wherehouse stored upright and not stacked with no exposure to sunlight. Are these tires still ok??? Thx!

From the Michelin UK website.

Quote:

How old is too old? The five year test
After five years or more in service, your tyres should be thoroughly inspected at least once per year. If the need arises, follow the recommendations of the vehicle manufacturer regarding replacing the original equipment tyres. As a precaution, if the tyres have not been replaced 10 years from their date of manufacture (see how to read a tyre sidewall), Michelin recommends replacing them with new tyres. Even if they appear to be in usable condition and have not worn down to the tread wear indicator.

So i would say they're probably ok if they've been stored correctly.

However on various forums you see posts along these lines along with warnings about second hand tyres. But no seems to bother to check the age of tyres when they buy a second hand vehicle - which will obviously come with a complete set of 2nd hand tyres.