D'oh! Not quite backwards, but i didn't know that a 3/32 chain comes in ss-specific design, and also missed one implication from your first post. Thanks for your patience.

I have resolved the sprocket confusion: i have one Shimano sprocket:

and one Sturmey-Archer sprocket:


According to http://sheldonbrown.com/harris/sturm...html#sprockets, the latter is 1/8" only, while the Shimano one is 3/32, which explains that particular confusion.

So to use my singlespeed wheel with (presumably) a 1/8" cog (i say presumably because they put the 1/8" chain on it stock) on my 12 speed, i'm going to have to put a singlespeed 1/8" chain on the biggest chainring and run it as a SS (which is what i'd intended, but wasn't sure if it would work), right? I realize that's super ghetto, but i need a beater bike and don't have any use for the ss wheel after i build up the Alfine, and the 12 speed rear wheel died...

Let me also hijack my own thread and ask if anyone knows about the quality of the Shimano vs. Sturmey-Archer sprocket, or of any better third-party models. This is for the IGH, so maybe i need to take this to a new subforum. The SA sprocket is a dull, dark grey color. The Shimano sprocket is a shiny chrome color.