Just a quick update. On 2002+ Q Pro frames, the Aeros fork bottom bearing race is 33.4 mm in diameter. The head tube lower bearing register is 1.750 inches (a touch less actually).
A Chris King 1 1/4″ Headset bearing has a 33.3 mm inner diameter and a 1.750 inch outer diameter. I have one press fit and loctited (w/ somewhat less permanent 262) onto my Aeros fork as of yesterday. I had to clean the steerer up with a bit of sandpaper after removing the way too permanently affixed original Klein bearing so I didn’t have the nice .1 mm interference press fit and I felt some read threadlock would help prevent it from coming loose in the long run but not bond it so permanently that I have to cut the bearing off. The angle on the inner race of the CK bearing interfaces perfectly with the bearing “seat” on the Aeros fork, so even if it isn’t a stupid tight press fit, it should stay in place just fine.
I’ll be loctiting (w/ 680 for a permanent bond) the assembly into my frame (it’s a nice snug press fit into the lower race) as soon as I’ve machined a shallow 44.40 mm register into the IS headset 45 degree angle head tube upper bearing location … where my 44.45 mm Chris King 1 1/8″ headset bearing will be pressed in with a touch of Loctite 609 (if tight) or 660 (if sloppy). At that point I ought to have an impervious Chris King Airheadset … without any adaptor cups.
UPDATE: Headset install complete … full pictures below
-David (Tycho)