KC,
Two things:
1- The weight transfer you lose from the inside tires is not an exact proportion to the weight gained on the outside tires.
Well, that can't be the case, at least on average, because weight and force are really the same thing here, and a force imbalance means that something is accelerating.
2- *IF* you did transfer all the weight (from the inside tires to outside), one more pound of weight transfer (in to out) and your inside tires are in the air.
Right. What I meant is that if you're taking the same corner at the same speed in the same car (with the same sprung CG height) with the same tires, and assuming that the contact patches on the tires are the same for both instance (something that is clearly not the case for the Mustangs when comparing a softly-sprung setup with a stiffly-sprung one), then the centripetal acceleration the body is undergoing is the same for both, which means that the tires are going to be under the same loading, which means that the force they're pushing back on the suspension with is the same, which means that the suspension is also under the same load, which means that the springs are also under the same load. The only difference to be found there is how much the springs have to move relative to their "unloaded" (car is going in a straight line) condition, and that difference is precisely because the spring rates are different.
It's not a 1:1 transfer. That's why weight transfer is undesirable. That's why it's common to hear "enough spring rate to stay off the stops". More spring = more weight transfer.
But "more spring" has to account not just for the difference in spring rate, but also the difference in available travel.
Which is to say you can stay off the stops using a combination of two things: increased spring rate, and increased available spring travel.
KC I think you would really like How to Make Your Car Handle. I got parts I would like to reference, but there is a ton of other info in there that I'm not gonna quote(the whole section) which you could read if you had it. In any case, this quote is in regards to the whole "springs always transfer the same amount of weight" bit, but I didn't have a reference for my statements previously. Pg 44 :
"The maximum limit to total weight transfer of the car is the total static weight carried by both inside tires. If the total weight transfer exceeds this amount both inside tires lift off the road the car tips over."Puhn
Right. That wasn't the circumstance I was thinking of, though. I was thinking of the more typical circumstance where the suspension had not hit the limits of its travel.
This is why I said in post 73 "I'm not sure about that last sentence" and that sentence I'm talking about is " the springs always transfer the same amount of weight...."
My apologies if I'm addressing something you already know.
No worries. I'm always interested in learning more! That book sounds excellent.
But as regards even the case where the situation has reached the point where the inside wheels start to lift, all that means is that the torque about the longitudinal line drawn through the contact patches at the outside tires of the car is enough to overcome the weight of the car, and the inside tires lift. It means that the outside tires have sufficient grip on their own to prevent the car from sliding under those circumstances. That is, I expect, the point of maximum cornering capability of the car. If the outside tires don't slip in the event that you try to take a corner harder than that, you'll flip the car instead. The corner would have to be banked for you to be able to take it any faster.
And that means that having the inside tires remain in contact with the ground won't help you in terms of making additional grip possible. You'd have to lower the car's sprung CG, so that the generated torque on the body is less for the same amount of horizontal force counteracted by the tires, to do any better.
Or so it seems to me. Hopefully my description above gives some sense of what I'm trying to convey here...