My reading about Shimano freehubs suggests there have been principally two: Uniglide and Hyperglide. Examining the spline pattern of mine as compared to pictures of Uni and Hyper, it would seem to be neither, and yet I find no mention of this mysterious freehub body. What is it?

More info:
The wheel is from a circa 1985 Schwinn Super Le Tour (though likely irrelevant, as I don't think it is original to the bike). 6 speeds - 3 cog cassette followed by spacers and 2 more cogs that drop in place, and the smallest that threads on with integrated spacer. The cogs that drop on only do so in 1 orientation (Hyperglide-like?). The splines follow a wide-narrow-narrow pattern, and the narrow ones are rounded, except for one. They seem to protrude less than pictures of other freehub bodies I've seen. The outer ring (which I've not removed) reads "HC Shimano China." I see no markings on the hub itself. I think the OLD of this hub is about 124mm (that is the spacing of the dropouts anyways).

What am I trying to do anyways?
I'd like to turn the Super Le Tour into a 1 speed bike. I actually have a Surly cog on order which, despite being "designed to fit on standard Shimano compatible freehub bodies," I fear is not going to fit on this one. I've seen videos, articles on swapping a Hyperglide body onto a Uniglide freehub ... not sure if that could be done in this case as I think the body is quite short (haven't measured it).

I would consider a new wheel, though I'd rather not "cold set" frame to increase the dropout spacing. I've wondered if I could pull them apart enough for a 130mm OLD hubbed wheel (haven't tried), though even if I could, I'm not sure I'd know what to look for ... maybe a wheel that just takes a BMX freewheel, or a wheel with the shortest Hyperglide cassette you can get?

Not a freehub body, just plain old freewheel.

My fixed-gear is an old 126mm-spaced bike. Just use about 3mm of spacer on each side of a (common) 120mm-spaced single-speed wheel and you're done.

*sigh* if only it were chrome and not brown

+1


Pull it off - you need a splined puller for that - install BMX-type f/w with an appropriate tooth count - and ride happily ever after.


For extra merits, move some spacers around to correct chain line, redish wheel, and ride happily ever after.


You'll need cone wrenches and a nipple wrench for that.


If you have access to a little more stuff, maybe scrounge some discarded freewheels of a shop, take these apart and use their spacers together with the existing sprocket of your choice to make a SS f/w of it.

Thanks to all. Apparently I didn't discover an undocumented Shimano freehub! The learning continues ...

If you'd just Googled-
Shimano MF TZ20

Incorrect. "Freewheel" and "freehub" are two somewhat different styles of mechanism. They have the function but the construction is different.

Good info: https://www.sheldonbrown.com/free-k7.html