Originally Posted by
JonathanGennick
The tread also picks up lots of little bits of gravel, which I took note of but it never bothered me too much. I expect somewhat similar results from the Contis.
The latter, I believe, is intentional - the gravel acts as low level studs. The very first version of TopContact Winter had shards of glass integrated with the rubber. After they adopted fine thread in Winter II they dropped the shards.