If you increase grip significantly and brake force then it makes sense that in the most extreme situation the rear wheels might aswell be free wheeling but I think brake balance comes into play the most in conditions where grip isn't so great such that in situations where prematurely locking front wheels aren't contributing much to weight transfer etc, it's all abit of a trial and error thing imo, you just test and adjust till it behaves lol
Any suggestion that it might be a good idea to try increasing the back brakes on a road car is just so wrong that I find it really hard to express how strongly I feel about that without risking being offensive. I understand that the maths may not be for everybody, but I have trouble with the attitude of "I don't know anything about the physics, but I know what I like".
And while extreme situations, like where the roads are clean and dry, may be unusual by definition; they do occur, even in W. Lancs. So a fixed brake balance has to allow for all the different conditions of grip that might apply. So, while it is mostly much better to have extra brake force at the back in the wet, etc., unless you can dial it back when it's dry, you just have to lump it. Since the rear brakes generally do so much less, that's not normally a big problem unless you really need to push the envelope. And you just should not be doing that on the road.
And it's not just in the extreme situations of grip. There's a safety margin that is supposed to allow for variations in road surface or where the front brakes are ineffectual when you start suddenly braking hard, e.g. because they are very wet, ect. So if you don't actually understand what you're doing in monkeying with (eroding) such margins, you simply cannot know what you have done is properly safe unless you test in all possible conditions that might ever occur (and in an entirely safe environment), including the ones you cannot reasonably anticipate. If you do engineering by tinkering with a safety related aspect (which is clearly not engineering by any proper definition of the word), you are making a big mistake. Possibly a grave one. The question then is whose grave.
For a largely unmodified road car, where there's little opportunity to massively increase the grip, the risks in sensibly upgrading the fronts are relatively small (I argue the need is also, but that's opinion); especially given how many have done so and can advise. I've done it myself, which is how I understand the result isn't really what most people think it is - it don't necessarily stop you any faster, just easier. So it's not unreasonable to do that and see if it gets you where you want to be. At worst, with a road car, it's a waste of money for a purely psychological effect. If you go too far, you lose some of the fineness in controlling the braking. But, the issues in brake balance need proper consideration and understanding before you even propose to upgrade the rear brakes of a road car. And the least of the potential problems is more expense to add some means to reduce the extra brake effort you just spent so much to increase.
And prematurely locking the front wheels does not contribute to weight transfer. Quite the reverse. If the front wheels lock first, the deceleration is reduced, and the back wheels get some of the weight back, and so regain some grip and require even more force to lock them. If you press hard enough you will still get them to lock. But the 4 wheel slides I've had didn't seem nearly as scary as locking the rears alone.
And who is this Lol fella, and what's he got to do with it anyway? Neli