I'll ask engineering.

I am guessing the hollows are a molding issue. Not sure it is a defect, but can they compress under load to start the flattening? Or is the lubrication more critical to prevent the wear?

Understand that we cycle tested these things in gritty water for tens of thousands of cycles.

Delrin. Voids are common in the extrusion process and not a concern.

I'd love to see a flat spot on the bearings up close. Curious to know if they are deformed from compression or worn flat.

Thinking of wear... A guy pedaled the length of the Mississippi. The water was fine grit... muddy. He was wearing through stainless parts.

Four of the 15 pieces in that sprocket have flat spots...some worse than the others.

Put it back together (mostly) and it pedals by hand silky smooth. No more squeak. I got frustrated trying to even out the chains so put it down and will finish that part a little later.

Don't leave us hanging. Did you make your own delrin bearings?

Sorry. I thought I had posted that. Yes. I used my Dremel to cut all 15 new Acetal copolymer bearings. I cut slightly oversized then sanded the ends flat...100 grit, 150 grit, then 180 grit.

Everything was easy except replacing the chains and idler cable. I'm gonna take another crack at that tonight.

I considered replacing all 30, but I have a feeling that this is going to become routine maintenance and I'll be tearing it apart again next year. I still have over 2' of rod left.

3 oz. of Super Lube is more than enough to do the job.

I don't know anything about the 180 drive, but my GT drives squeaked all the time and that was driving me crazy, as I'm constantly pedaling. My solution was to replace the delrin bearings with nylon bearings, and use one less bearing per shaft. It's silent now, and that's without any grease or any other type of lubricant. I've put at least 1K pedaling miles on my GT drive since making this change, almost all in saltwater. I've had no noise issue and I see no sign of wear on the nylon bearings or stainless parts.