I purchased 235 60 R 18 tires for 7000 pieces two years ago, which are generally worthy tires for this price. These are considerably softer than Dunlop Sp 270, and while Danlop was worn down to the cord by 50,000 miles, I drove 30 thousand miles on these, which you cannot see. The stones that jam into the tread and then shoot out at high speed, but not all of them, are what cause the noise; as a result, we ride on the "stone spikes" that produce this rumble.