Originally Posted by
urbanknight
..doesn't the hub experience some torque when the brake makes the rim want to stop while the hub wants to continue moving with the momentum of the rest of the bicycle?
Think of it this way:
Any force generated by the brake, is effectively balanced by the force generated by the friction at the contact patch between tire and road surface. It's a zero-sum game.
Basically, as far as the hub and spokes are concerned braking will "look" just like the rider suddenly became a tad heavier.