antidive and ride quality

[71roadster]

If I am understanding my own analysis of antidive the SVSA IC must be above the center of the wheel which means the rear mounting points of the control arms must be higher than the front (axis points up to rear), but this also means the wheel will move forward on bump which has to translate into a very rough ride. Obviously the manufacturers build in prodive so the wheels move rearward on bump to give a smoother ride.
My LCA seems to have a horizontal axis and the UCA points down to the rear. While I want to improve the handling as much as possible I don't want this to be a miserable ride to and from the track and the occasional weekend jaunt.



I am just wondering if there is a happy medium somwhere?

Chris

[79T/Aman]

if the front wheels moved forward under braking that would cause the tires to slide and give you poor braking perf.as this would be added to the forward momentum of the car

[Norm Peterson]

Antidive % is positive as long as the SVIC is above the ground and you're using "normal" outboard, or suspension upright-mounted, brakes. It's not necessary that it be above axle centerline; with this arrangement that's a consequence of a long enough SVSA combined with a high enough antidive %.

OE arrangements are not necessarily pro-dive, just not huge + values. Perhaps there's enough OE A-D in conjunction with the front spring rate to keep the average driver's hard stop from crashing into the bump stops too hard and damaging them. Or maybe enough to meet some pitch requirement (degrees pitch per longitudinal g?), or some limit on caster change or even bumpsteer.

Note that the A-D for inboard front brakes that work through half shafts to the wheels would behave as you've described, though. But that's an unlikely arrangement without the front wheels being driven.

And yes, there should be a happy medium somewhere.

Norm