Re Mr.Fox's posts, gravity extensions are done on jacks in the hangar usually after major gear maintenance. Without hydraulic pressure and air flow to influence bogie position it usually tilts to the heaviest end as you might expect.
The A330/A340 main gear is a special case. The nose up tilt is indeed intentional and is meant to act a bit like the 777-300ER's semi-levered gear in improving aft fuselage clearance. However, on retraction the gear actually shortens and this process removes the bogie tilt as it retracts so the bogie is parallel to the fuselage centreline when in the wheel well. The shock absorber strut slides inside the main fitting (the undercarriage leg) and is pulled up inside the leg as it retracts which removes the bogie tilt as well as shortening the length of the whole landing gear.
See video
https://www.youtube.com/watch?v=-_z-KBTZRVk