It basically means nothing. The use of ABEC ratings was an accident in inline skating. It is about bearings used in machinery that runs at extremely high speeds. Nothing about rolling better under the weight load or speeds for inline skating. Some of the bearings used for the early inline skates were so poor that any ABEC rating guaranteed that the bearings were reasonable. Then the manufacturer's got their advertising people into the act by bragging about a number that isn't important or expensive.
