Quote:
Originally posted by wrm
Me two, thanks. 
While I have many other suspension design books, I dont have Carrol Smiths, maybe someone can explain to me why Carrol Smith doesn't design anti-squat into an IRS. While I understand an IRS is limited to around 25%, surely 25% is better than none.
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WRM,
Look, Carroll doesn't like it for the same reason that I do not like it. You cannot control the dynamics with mechanical leverage of this type.
The more you load the anti-squat/dive geometry in the chassis, the higher the resistance to motion without a basis of control.
As Bob stated, the transfer is nearly instantaneous and this is a out of control condition for a circuit type car.
One must control dynamics with wheel rates and dampers, not geometry lock ups.
Milesdw,
Quote "As you say, there is no way to increase weight transfer but anti-squat DOES increase rear tyre loading and thus traction. For an IRS anti-squat also has the benefit of minimizing any camber change due to suspension compression."
Well this is only partly true. On a perfect surface, one wishes 100% weight transfer. In a time frame that does not exceed tire spring frequencies. (Note: This is very important.) Load on a tire can only go so far before you exceed the available slip angle. Sidewall Hysteresis is also a consideration.
But in overall chassis design and setup for a road going or circuit type chassis and it's given application, any mechanical or geometrical binding is the wrong thing to introduce.
This is due to it not being controlled from a time based standpoint.
Transient behavior is the most difficult thing that a designer has to deal with in any chassis design.
And any anti squat-anti dive stuff just puts a chassis out there where you will never get it to work properly.
You do not need to take my word for it. Just read books by folks who have a clue. Or better yet, speak to some designers who are current in the art.