Those were junk tires anyway, maybe the Ecopias would have done good but I'm going to stick with 13" for now. My rear tires don't have much left so I'll keep them for the inspection. I'll put the front tires on the rear and mount on the front the 155/80 R13 I just bought (what Piwoslaw recommended me in the first place
). They are Yokohama Bluearth, one of the best for 13" as regards efficiency.
My last tank is good : 2,78 l/100 km for 82-84 km/h cruise speed. No front wiper and more EOC than usual (for 500 m idling). I also began to bump start to save the starting motor and the battery. It's probably my best MPG/speed ratio tank. I was driving only 75 km/h when I lastly got 2,77 l/100 km.