More downforce = more negative camber can be used?

[g-force_addict]

More negative camber increases cornering force by camber thrust
up to a point where too much negative camber causes the outside of the tread to lose contact with the pavement thus reducing contact patch size and grip.

As depicted here

Where the left side of the trad loses contact with the ground.

Does additional vertical force (like downforce) allows the tire to compress as to allow the left side of the tread to regain contact with the ground, while still generating additional camber thrust and cornering force?

Simple logic says so.
Are there some camber vs grip charts at different vertical loadings to confirm or deny this?

[Greg Locock]

"Are there some camber vs grip charts at different vertical loadings to confirm or deny this?"
yes there is, you need tire F&M data at different camber angles. I'll look at some later on today.

Having said that camber thrust is small beer and as your picture shows, more negative camber will increase tire wear on the shoulder at low speeds.

[Greg Locock]

Hmm, turns out we don't test tires to their peak mu at high camber angles, so I can't tell. Here's the best graph I've got, run at several increasing vertical loads. It does look as though the higher Fz runs benefit more from the extra camber

[Luke]

More downforce also means more lateral force, which means more lateral distortion of the tyre effectively reducing the camber at the contact patch.

As you mentioned also the higher vertical load compresses the inside shoulder bringing the outer area of the tyre into contact if it wasnt before, or increase its surface pressure more than it had before.

BUT the tyre will have a harder life with both higher vertical load and higher camber dramatically increasing the distortion of the inside sidewall per revolution, meaning overheating down the straights and tyre failure could occur. But its always a balancing act of staying just below the failure point.

[Greg Locock]

I realise I've turned gfa's question inside out, without better data I can't tell if the optimum camber is more or less for a highly loaded tire.

[Jersey Tom]

I'd say fairly often you are durability limited, not performance limited when it comes to camber.

Could very well need to run less camber as you start piling on downforce... with higher cornering speeds, loads...