Knobs are starting to come off of my cinder tires. Only lost one but usually means more to follow. Had that problem with other tires but not after only 5 or 6 weeks of use. Has anybody else experienced that????? Using it for mountain trail riding rocky terrain. They grip like a goat in the mountain but if they won’t last may need some replacement suggestions????? Lately used Continental gravity & verticals last MB. They are probably heavier and doubt if they grip like the cinders, two things I don’t want in tires. MKIII Expert is an awesome awesome bike, literally taking it to the next level!