zero droop

[JohnD]

Can anyone explain the 'why?' of zero droop for me, please?

I'm studying suspension, and receive the lesson to adjust (an FF in our workshop) for zero droop, front and 20-30mm droop back. I can't understand why, in corners, and the explanation is something like - it lets you go faster - which isn't an explanation.

I think I can understand this in a straight line start; as the car accelerates, weight transfers to the rear and the front lifts. If the suspension will not droop, then the weight transfer is limited, until the rear tyre reaction is so great as to lift the whole front end of the car. The tyres remain on the road as far as possible and steering is maintained.

But cornering? Weight transfers to the outer wheel, and that side of the suspension compresses, while the inner side would move into droop as the car rolls. But it can't, because it's already in zero-droop.

To me, and because the side forces are not lifting the whole car's front but only one corner, this would cause the typical Mini cornering stance, with the inner front wheel in the air, with no traction/grip at all.
Understeer is inevitable, but I am assured that this will keep the inner wheel on the ground, with little weight on it, to be sure, but enough to help prevent understeer.

As for rear droop at sucha small figure - Gok!

I'll be grateful for some discussion.
John

[ydd]

John - that does seem like strange advice.

The aim is to keep as much tyre contact patch in contact with the road as possible. Further, you want to minimise lateral load transfer to maximise grip. By limiting droop, you are effectively increasing stiffness.

Hope you got it sorted in the end.

[Spetz]

Is this perhaps used in MacPherson strut FWD cars where camber gain is minimal and roll centre is more erratic, hence removing droop is used to limit the jacking effect of the inside front wheel to maintain the right camber on the outer wheel?

[kevski996]

You need rear droop otherwise when cornering and in roll the rear will lift if restricted droop is met, you then get sudden loss of rear grip as the inside wheel spins up and round you go with snap over steer.

[JohnD]

This was on an FF, Formula Ford, car. Double wishbones front and back, so not to do with McP struts.
Yes, droop allowed in rear, but ZERO droop front.

Can anyone explain, please? We had to move on at college, so I never did get one there.