Quote:
Originally Posted by nickelplated5s
A shock is a shock Bill so not moot. My question is what A:C ratio? I've heard of spindles being raised 15mm to 40mm. Obviously A has changed over the years due to tire and rim choices. I understand early R's had the 19mm raise. I don't have the data for other changes. RC=CG?
Show us a pic of your rims P, please. I'm partial to my Fuchs though. Curious as to the motor and brakes too.
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all you care about is the absolute relative heights, not the ratios.
follow the notionary line perpendicular to the shock top mount out to where it meets the notionary line extension of the A-arm, they meet at the 'Instant Center'
then follow another notionary line from the IC to the center of the contact patch,
the intersection of this line and the vertical line thru the Center of Mass is where the Roll center is, the RC is the axis around which roll takes place, it is not a fixed point it moves around at the behest of the change in A-arm angle
b is not fixed either, it also changes as the result of A-arm angle i.e. suspension bump/droop
all roll forces act through the CoM
The distance from the RC to the CoM is the lever arm that all roll forces act on, the longer is the more roll.
In the following diagram the car has been lowered by adjusting the the t-bar adjusters.
a is constant
b has gone down and w/ it the height of the steering rack
a -b has gone up
IC has gone down, taking RC w/ it
CoM has also gone down, but not as much as the RC
here A1 is the stock lever arm length and A2 is the arm length when the car has been lowered
here you see the stock relation between shock top, t-bar, a, b, rack and knuckle
here the relationship between them when lowered, b has gone up, no compensation to rack or knuckle height here, either the rack goes up, the knuckle goes down or some combination of both is needed to compensate and get b back to spec,108+/-5 mm
