Hmm. I tested 6 pairs of 2.5 mm BB adjusters with the 2.5 mm titanium rod end threads. Dead positive that the thread size is 2.5 mm. These were brand new adjusters with no wear and no previous threading. In each case, after fully threading the adjuster to the max depth, I could separate the the adjuster from the rod end by pulling with my fingers.

Maybe I am unlucky, or there is some variation in the adjuster hole size? I've heard Troy talk about this. I think it is a known problem. Yes, the package says 2.5 mm, but in my experience you will not get a snug fit.

Edit: I don't mean to beat this to death. Obviously, we have had different experiences, and because of that I decided to take some measurements. I found that the hole size of a new pink 2.5 mm adjusters is 2.336 mm. On the titanium rod ends that I have, the diameter of the bare shaft is just 2.18 mm, and the diameter of the threaded portion is 2.337 mm. I also took the measurement of a 2.5mm screw, and the diameter is 2.54 mm. I have to conclude that the problem is in the titanium rod end diameter being far too small. The 2.5 mm screw that I have does indeed fit the adjuster snug, and I would have no fear of flying with this fit. However, I think I either received a bad batch of 2.5mm rod ends from Central Hobby, or you guys should double check how they fit before you fly.

David