Sorry ... I get the unit mixed up. I mean the tire pressure was previously set at 2.5 bar, which was then later changed to 2.1 bar.

Mercedes recommended tire pressure is 2.1 bar.

My point is, I noticed the higher-than-recommended tire pressure might be the culprit of the excessive worn out of the first pair of Yokohama tires. Then I changed the tire pressure to be within the recommended tire pressure, which seems to help a bit only. This latest pair of Falken tires are about 85% worn out only after about 10,000 km!! So far I have onwed at least 10 cars before and almost any brands of tires I have used before can last at least 20,000 km. And, for this car, the excessive worn out only happens at the rear and the left back is more serious than the right back ... so I just recken something is not right.