Surprise has been expressed about the presence of pre-rotation on the nose landing-gear tires as described HERE. The need is a little more obvious when you realize how long the nose landing gear was with the shock strut fully extended. When the nose wheel touched down, the load of the initial drag of the tires on the nose landing gear down-lock mechanism was magnified by a very long lever. (If you're in a window seat beside or aft of the main landing gear of a de Havilland Dash Eight, you can get a pretty good idea of the loads involved when the wheels meet the runway on landing.) Pre-rotation of the F7U-3 nose-gear tires reduced the kickback load.