I ordered tires, Silvertown Radials, from Summit. One of the tires has the following date code (5015)! 50th week of 2015. Mid December 2015 (it's 8/17/17 today). Too old for me, it's going back. This is after three employees at Summit said they rotate the tire stock and the tires will not be more than 6 months old. How about you? How old is too old for a "new" tire?