I am driving a C180 and it has an unknown Simes brand on it which has quite big threads, but does not make any noise at any speed. My previous car, a Camry was using Goodyear tyres which looked quite normal, but really made a big noise especially at highway speeds(100kmh) and also made the steering wheel vibrate very uncomfortably. Found out that they were ? defective as they were not really round in the sense that they had flat spots and were only 6months old. Changed to Bridgestones and the noise immediately disappeared together with the vibrations. There were some "techs" out there who were going to help me spend some of my little money to change shock absorbers, springs, engine mounts, mufflers, bearings and brake discs!Yokohamas are really "soft" tyres and should give a quiet roll at all speeds. Some tyres get flat spots when left for too long in parking mode. Good luck.