While putting Tangerine Dream together a couple of days ago, I carefully adjusted the main cap bearings so that they wouldn’t bind. When I mounted the unicycle, it made a loud creaking noise. I checked the saddle bolts, seatpost, spokes, usual suspect list. I found that I could stand, hold the saddle in my hands, and twist it and it would creak. I isolated the sound in the maincap bearing holders. I overtightened the bearings and the creaking went away.
To solve this problem, I removed the wheelset with the bearings attached. I noticed at this point that Darren Bedford had glued a fiber shim of just the right thickness onto the main cap bearing holder half welded to the (shorter) fork. Another plus for Darren, taking care to assemble the unicycles before shipping to see if anything needs to be taken care of ahead of time. I put a very thin film of grease on the outside of the outer bearing races and then reattached the wheelset and readjusted the bearings.
No creaking and the bearings remain adjusted properly.