ORIGINAL: pe reivers
Sport, That is the axial play of the ring you talk about. The dimensional wear I talked about is the radial wear. You can either measure it by ring end gap measurements by placing the ring in a part of the bore that does not wear, OR you can measure the ring cross section directly. For the latter measurement you need to know the dimensions of the ring when it was new
(very often not known)
OK, but I don't understand how that wear is hard on the lands, and come to think about it the land gap wear is mostly from the pistion lands deforming, not from ring wear. Ahh, perhaps because sloppy ring fit causes them to bend up and down in the gap. But are you talking about this wearing the land top and bottom width, or the bottom diameter?