Ryanair flight 9513, a Boeing 737-800, lost a wheel of the nose landing gear shortly after touchdown on runway 07 at Venice-Treviso Airport, Italy. Speed at the time was about 100 knots and the aircraft yawed slightly to the left. The rollout was continued without incident and the aircraft taxied to the stand. It appeared that the nose landing gear axle had failed at 15309 cycles since new, which is 1/5th of its expected lifetime. PROBABLE CAUSE (translated from Italian): The cause of the accident was a breakage of the front wheel axle, which caused the front left wheel to come off during the landing phase. The axle rupture occurred due to a stress corrosion phenomenon triggered by a preliminary generalised corrosion attack in the most stressed area.