Bought the GLC250 a year ago, my 5th mercedes. I have to say , it is the worst car I have ever had!
They have what Mercedes call a characteristic of the car . In that the front wheels when you turn a sharp corner , you get this very loud and knocking, and feel like the car has absolutely no grip on the road. They call it “Crabbing”. Apparently this is due to the car originally being built as a left hand drive, which doesn’t quite work so well on a right hand drive. Mercedes also recommend that you replace all the tyres with All Weather tyres, as this seems to improve the grip. The tyres will dramatically wear on the outside edge, and this is nothing to do with the tracking. I suggest you test drive one , and check the full lock yourself. When I approached Mercedes customer service, I was told to just buy new tyres at £1200. Not there problem, as they class it as a characteristic, and not a design flaw. Despite the obvious problems. I have even been stopped by other GLC drivers asking me if I had the same problem. So I assume it is fairly common. I also spoke with the Motor Ombudsman, who also said that they have had numerous calls regarding this issue.