Flyboy767 From , joined Dec 1969, posts, RR: Reply 2, posted (13 years 3 weeks 2 days 1 hour ago) and read 4470 times:
I believe the reason that only the outer bogies tilt is because they are the first wheels to touch the ground, the inner bogies don't touch until more of the weight comes of the wings and onto the undercarriage...until the aircraft starts to pull the nose down to the ground after flare, there is not enough weight on the undercarriage to make it necessary for all 4 bogies to be supporting.
UAL747 From , joined Dec 1969, posts, RR: Reply 3, posted (13 years 3 weeks 1 day 23 hours ago) and read 4467 times:
Actually, the inner bogies touch before the outer ones. The inner ones are slightly farther back, and as the aircraft flares, the back ones naturally touch first. There are some pics on this site of aircraft flaring or rotating where the inner bogies are on the ground and the outer ones are in the tilted position.