Today when I was checking my tire pressures at the gas station I noticed a screw in my passenger rear tire. I wasn't losing any pressure at the tire though, so I wasn't too worried. There was a Tires Plus right across the street, so I pulled over to see if they could repair it. After looking at it, they decided the screw had punctured the side wall and thus was not repairable. Considering the tire is still holding pressure perfectly I decided not to put the (stock) spare on. My dilemma is this: I bought the car in June and the dealer replaced the front tires only at that time, the rears still showed plenty of tread left. So I have 2 Kumho 711's on the front (only 7 months old) and 2 Dunlop 5000's on the rear (don't know the age). My plan originally was to just drive them for a year and half (or however long) without rotating, then replacing all 4 with a matching set. Now my hand is called - should I bite the bullet and order 4 new tires now or should I buy another pair of Kumho 711's to replace the rears and have a matched set of different ages. Maybe go ahead and move the fronts to the rear and put the 2 new ones on front? What do y'all think?