[sik68]

I would venture to guess that caliper position on high end cars like F1 is mostly dictated by efficient airflow in that area for brake cooling.

I agree that caliper position affects the wheel bearing loads during braking, but not the resulting load on the tire.

If caliper position did change the load on the tire, then under hard braking the tire could go into an "open feedback loop" and your car would a) become infinitely heavy and crush through the earth (3oclock), b) speed up (6oclock), c) levitate off the ground (9oclock), or d) instantly stop (12oclock) just by pushing harder and harder on the brake pedal. :p Just exaggerating for visualization purposes.