Sorry, I do not know the answer to that. Since Black Ace is not part of the Q series, I would be inclined to think that it has micro bearings all around the hoop, but it is only a conjecture.
Pete had better intestinal fortitude, serve, volley, half volley, overhead, and running forehand.
Pete was also the undisputed best of his generation, not the 3rd best.
It’s about percentages, and his overhead has improved tremendously.
If he had missed a forehand or backhand from the baseline in the same/similar situation, would it make it an unreliable shot?