Have you ever wondered how old your new tires are? According to the DOT all tires have to have a date code on them. They do sit on shelves and could be there for years. I personally do not buy tires that are more then a year old! My experience is that when your tires get old they get greasy (slippery). I would not ride on tires that are over 4 years old.

Taken from MotoTireGuy

Every US Department Of Transportation (DOT) approved automotive and motorcycle tire has the tire date of manufacture stamped sidewall. The format of this date appears in a WWYY format, as in week/year. For example the manufacture date code of 4407 translates to the 44th week of 2007. Tires produced prior to the year 2000 use a three digit code. For example the manufacture date code of 378 translates to the 37th week of 1998. New tires should be less than 3 years old. I recommend discarding used motorcycle tires after 8 years of age.

Good Stuff, thanks

Thanks again OP - I just used this little tid-bit to make sure I got a good one -
4413 - or about 5 months old - still smells up the workshop really good so...

My tires never see 6 months of use, maybe a year for a front, as far as born date they are always just a month or so old. The person I get them sells a lot of Harley tires

Good info. I read some where rubber has a five year shelf-life, after that they will harden and become brittle.