Hi. I've got some silly basic questions regarding drivetrains and width compatibilities. My new bike is a Tricross Singlecross (singlespeed); it came with a KMC Z-510-HX chain, which is described as a 1/8" chain. I'm in the process of building a respaced Alfine hub into a wheel for it. I'd like to repurpose the original wheel for my old Nishiki road bike, if possible.

Now for the questions: (1) Will any cog work with this chain (for the Alfine), or need it be a "wide" cog (i.e. 1/8-specific)? I ask this because i have an old cog for the previous-generation Nexus8 and it noticeably narrows at the teeth, but they are both said to be compatible with the Alfine. (2) Will the existing wheel/freewheel work with any other chain (e.g. can i put the old wheel on an old 12-speed)? (3) Can an 1/8" chain work with a chainring intended for a 6- or 7-speed (e.g. if (2) won't work, will it if i change the chain to a wider one)?

So, yeah, basically, can 1/8 chains stay put on gears intended for narrower chains and do the job just as they ought? I guess that sums it up.

Thanks for your help.