GL1800 tire cupping

imported post

Cupping is the uneven wear between the sipes (grooves) that run from the center to the outside of the tire. The leading edge of the blocks between the sipes tends to pull out and be scrubbed off when cornering. This results in low spots on the tire that are cupped thus the term "cupping".

imported post

Cupping will normally occur left of center of the tire, that's where you will see it first. In Europe I am told it is more prevalent right of center. Why? We drive on the right side of the road and they drive on the left. Roads are crowned for drainage, that crown will help bring it out faster on one side over the other.