A less-common Japanese road bike....

[juvela]

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I have the same crank and derailleurs for my Miki (and Sunshine hubs). I think the taper is Suginos own as ISO came later but they are both similar the old campy taper. I just used 70s Campagnolo Record BB with the Sugino Super Mighty crankset.

I think the common square taper widths or profiles are
Narrow: Ofmega
Medium: ISO, Campagnolo, Gipiemme, Sugino, most NJS square taper?, Omas, some old French spindles like Nervar, Mavic and Stronglight
Wide: JIS(Shimano, SR), some French spindles (TA?)

Does anybody know where the 171mm crank arm lengh comes from?

the 171mm length is the metric equivalent of 6 3/4"

was widely employed on early Sugino products

much the same that the 71mm shell width was much employed in Japan for a number of years as it is the equivalent of the Raleigh 26TPI shell


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