Used to be all knew that on rear wheel drive the better pair of tires goes on back. On front drive better pair in front. I have switched to all wheel drive where 60+ power goes to rear so I put best rubber on rear. Recently gave co-worker concensus opinion on her front drive to put new pair in front, leave OK pair on rear and toss the baldies from the front. She called from the tire shop to say they wanted a disclaimer to put new pair in front. Per the manufacturer. (GM). I researched on line and found manufacturers switched over last ten years from good pair in front to good pair on rear. Regardless of drive! Can anyone explain this?