Ya know, that myth about synthetic making bearings skate instead of roll has been around ever since synthetic oil came into being. Most people who were educated on what synthetic oil really was realized that it was the best thing possible and ideal for a hot running air cooled Harley engine. Since Harley didn't market a synthetic oil at the time the standard tactic that some dealer mechanics utilized and some actually believed was that it was so slick that the bearings would skate. In reality it would be great if they were right because if a bearing skated instead of rolled it would mean almost ZERO friction thus no wear what-so-ever. You just can't get any better than that. But the reality is that synthetic means that the molecules are all uniform in size which makes more consistent contact with the metal making less friction allowing it to do a much better job of lubricating...less friction thus less heat, thus less wear, thus better in doing the job. It also doesn't break down at higher temperatures as readily and holds it's lubricating properties much longer. It's not the breaking down of the lubricating properties of a synthetic oil that makes an oil change necessary but the contaminates of combustion that will eventually collect enough acids and contaminates to be detrimental to the engine. If it wasn't for that fact the lubricating properties may last for 100,000 miles or more like the synthetic manufacturers first claimed when it first came out in the 60's at $40 a quart.
There is nothing magical or mysterious about synthetic oil. It's just ideal for Harleys. Now that Harley markets their own synthetic (well, not 100% synthetic) it's rare to find a dealership whose mechanics make the false age old statement about bearing skate. Maybe it is by some guy who has been locked up for a while and took up where he left off many years ago? baha