Just had a customer call me looking for tyres for his bike as his had expired, when I delved deeper, I found he was referring to the manufacture date of the tyre. He was super relieved when I explained that was the date it was made, not the expiration date. So for those buying a bike, or have a long term project, have a look on the side wall and you will see a 4 digit code, this code is stamped on the tyre and shows the week and the year the tyre was manufactured. Ror example 1214 means the tyre was made in the 12th week of 2014 , 5117 means 51st week of 2017. Rule of thumb, most manufactures recommend changing your tyres if they are over 5 years old Some know this, other don't, so I thought it was post worthy
The numbers next to the tyre size and profile mean something too. Eg. 110/70 R17 54H. 110/70 is the size & profile 17 or R17 is the rim diameter 54 is the load rating H is the speed rating The numbers/letters should be checked against the manufacturer website.