SAG was first seen (in my experience) in owners manuals for off road racing bikes (somewhere in the early eighties?). You would measure the bike without the rider and measure the change with the rider on it. For motocross riders of similar weight and size that method gave a good starting point for most users. That is the method I was referring to.
there are less limitations when measuring total sag vs riders sag, esp with linkage ratios on rear suspension. total sag is actually a valid reference point for all riders, not just ones of similar weight and size. its still not a great reference point, but oh wells. ppl that know nothing about their suspension need to start somewhere.
(under load=full cornering speed with the proper tire, that's the point where your adjustment needs to be right not the static load)
:wtf thats a very limited way of looking at the "problem" of suspension.
suspension position needs be to "right" under ALL loads, including the static ones of rider or total sag. hell, changing the sag affects the dynamic position of the suspension under all loads. so that change can be felt under all riding conditions, including the really important ones like hard braking and corner exit. no one that knows what they are doing tunes suspension for only "full corner speed".
