Explain 3 link please?

[Raceral]

I under stand the short bar lets you control pinion angle. The long bar lets you center the axle.
Why would you want a piece that is allowed to move around rather then fixed. Isn't center the spot you want it?
I'm trying to give folks a good answer that drop by the house a good reason . All I know is its suppose to be better then 4 link, but not as good as IRS.
School me....

[Jeff Kleiner]

In a nutshell; it allows the straight axle rear end to move throughout it's range of motion without the inherent bind that the 4 link has.

Jeff