andylaurence wrote:@machin - I don't understand how your theory that reduced load transfer increasing the grip on the front tyres under braking being offset by the increased load of the rear reducing their grip works with your statement earlier that the Deltawing is not as good because it has greater lateral load transfer. How is it different?
Given equal weight, CG height, width etc the two cars should have the same TOTAL lateral load transfer... The Deltawing has less lateral transfer at the front (a good thing; not only do you get more grip when loads are shared equally between tyres by virtue of the shape of the grip curve, but also because the braking performance of each end of the car is determined by the most lightly loaded tyre, the inside tyre, the point at which locking occurs will be higher if load transfer can be reduced). The problem with the Delta wing is that more load transfer occurs at the rear than a equally sized rectangular car; again, by virtue of the shape of a tyres grip curve this means less grip and also means the inside rear tyre is even more lightly loaded than a similar sized rectangular car where the load transfer is shared, so will lockup easier.
Now throw a constant radius corner into the mix... the front has more grip so theoretically could go round the corner faster... but the rear has LESS grip.. so it breaks away sooner... the car has to go round at the limit set by the 'weakest' end of the car; in the Deltawing's case; the rear.
If the rear tyres provide most of the braking effort, then if all four wheels lock up, the car will have a tendency to straighten up under braking, feeling more stable. That, I think, is the point being made about braking stability.
The problem is you always get one tyre locking first by virtue of slightly different loads on all four tyres.... you never want a rear to lock first because that results in spinning... so you bias the brakes slightly forward so that one of the fronts lock first (ideally none of them should be locked of course!).
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