Re: What kind of rear sprocket needed for a NuVinci hub with SBP shift kit?
Thanks to everybody for their thoughts!
Pops - here is a picture of my freewheel adapter (notice no freewheel on there yet, I've decided to try a 16-tooth but still waiting on the mail). It's very solid - the adapter, splines, and hub all feel like one piece. I did some looking around online and found out that the interior diameter of an English threaded freewheel is 1.37 inches - this is exactly what this adapter measures over its threads. If yours has some play in it, maybe you could contact NuVinci (Fallbrook Technologies) to ask about a replacement adapter?
Let me know how your install goes - I keep getting sidetracked but hopefully I'll be able to get this one up and running in the next week or so.