Originally Posted by
MnHPVA Guy
Those are tandem cranks alright, you can tell from the chainring adaptors. Up until 1977 Paramount tandems came with TA 10 speed tandem cranksets with the timing chain on the right. Someone needed room for a 3rd chainring so they got another right front arm and installed it on the rear on the left side, and swapped the front arms left for right.
The fact that Schwinn mounted everything on the right side does not make them tandem cranks. Tandem cranks according to TA foresaw left cranks fitted with chainrings and reverse pedal threading. Using standard cranks was an expediency that worked perfectly well as long as you were OK having two usable chainrings for the drive chain. On track tandems, it is commonplace to have both the drive and timing chains on the right.