T.A. Crankset and Le Tour R/D
 

170 arms 54-40 rings $75 shipped
R/D SOLD
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I don't think I have ever seen inner ring protectors like those. I cannot figure their function. Must be my old brain.

Schwinn used these on the Sports Tourer in the mid 1970s, along with Nervar cranksets. 54/40 T was a big gap...

I found the exact same crankset at our co-op. It is a bit odd.

As noted by others above, that crank configuration was stock on the Sports Tourer. The extra ring is ramped to facilitate shifting the large jump between inner and outer rings:

I did pull it off a Sports Tourer. You guys are good.

Ach soooo. Veeery interesting. Thanks. Learned something. Cool.

There was also a 5-arm Nervar ramped ring like that for Schwinns that got a Nervar crank.

I like the way that crank looks. Those are some of the prettiest chainguards (/chainramp?) I've seen. I think this would polish up and present very well. For someone that uses 170 cranks, the look and the gear range would make this go great on an all-rounder build with vintage silver components.

GLWS

I've always found those ghost rings to be very unsettling to my eye, though fittingly psychodelic for the time. I would be very tempted to take off the guard and ghost ring to see how well it works in normal configuration.