(all caps added for emphasis on possible confusion points)
madin88 said:
On a 4-bar the swingarm is split into chain stay, seat stay and rocker as you can see.
The rear SUSPENSION of the diagram above is the swingarm, upper A-arm, rocker arm, frame (not shown, but is the base of the system) and shock. The wishbone is just the bracket that attaches the rocker arm to the swing arm and is considered part of the swing arm. So the rear SUSPENSION SYSTEM 4 bar linkage is the swingarm, upper A-Arm, Rocker arm and the frame. The shock dampens the motion and suspends the weight yet doesn't dictate directional motion (if they did the math right, if they did it wrong they shock won't last long which is why I think in another pick the shock to rocker arm had another link).
madin88 said:
By doing so the virtual pivot point can be moved far forward to prevent squat during braking or pedal bob.
I am no expert, but doesn't the Surron have a fixed pivot point?
The attachment of the SWING ARM to the frame is a fixed point arrangement. The swing arm IS NOT the entire suspension system. Just one part. There are 4 bar linkage SWING ARM setups out there, the SunRon isn't one.
But this is a 4 bar linkage SUSPENSION setup. The swing arm, on it own, is a single point arrangement, as is the upper A-Arm, on its own.
So you are correct in the SWING ARM being of a single point type, but the REAR SUSPENSION SYSTEM is a 4-bar linkage. It's the difference in saying that the rim is the wheel vs saying the hub, spokes and rim is the wheel. You are referencing a particular part of the entire system, instead of the system as a whole.
I hope this helps clarify.
Now if you really want to bake your noodle, look up Honda's Unit ProLink rear suspension used on their MotoGP bikes. The entire rear unit is held on with two bolts. The shock compresses against the suspension set up and NOT the frame.