I just learned that in fact, some “synthetic oils” are not even truly synthetic. Below an explanation written by Spectro Oils Of America.
“Spectro® Platinum Synthetic is, without doubt, one of the finest synthetic lubricants you can buy today, no matter what kind of motorcycle, snowmobile, PWC or racing car you run. Why?
Because it is a true synthetic. Spectro Platinum Synthetic is crafted from modern Group IV PAO (polyalphaolefin) synthetic base stocks. These PAO molecules are assembled from the ground up to provide superior strength and endurance, no matter how hard you push or long you punish them. The Group IV synthetic molecule is thus engineered from scratch to better resist being sheared in the gears, and to fight degrading oxidation due to high temperatures.
(The competitive Group III petroleum oils — adjudged “synthetic” in the course of a long, contentious legal proceeding — are just typical mineral oil molecules which have been refined to a higher level than standard petroleum. They are fine oils, we would agree, but they are not purpose-built starting at the molecular level to deliver maximum endurance.) The advantage of true 100% synthetics isn’t measured in lubrication qualities like “slipperiness”, but more in longevity and “usability”. Easier starting at any temperature, less reaction to temperature extremes, greater durability and resistance to breakdown through molecular shearing.
Spectro Platinum costs more, but delivers so much more longevity and security. So when you’re offered a “synthetic” at a lesser price than Spectro Platinum, chances are good you’re getting a lesser product” Spectro Oils Of America.