Ride Height, Suspension Geometry and Tire "Squish"?

[BBShark]

I would like to know how how you account for tire "squish" when all of the weight (of the finished car) is on the tires. I thought this dimension might be negligible but I measured my daily driver and came up with 1 1/2 inches of difference on a 28 inch diameter tire (distance from ground to center of wheel = 12 1/2 inches). That is significant, big time.

I see a lot of people on here and other forums laying out suspension geometry. I have always seen this done as though the tire has no "squish". This makes the assumption that the centerline of the spindle is centered on the tire.



In my example above, that would be completely wrong. The centerline would actually be 1 1/2 inches lower at ride height! The suspension geometry would be COMPLETELY different from what had been calculated!

So, can someone tell me if this number is published by the tire manufactures or if it is ignored by builders or if anyone has any information about this or?