I do not consider myself very knowledgeable on Schwinn but I’ll put this out there as a possibility….
The catalogs are confusing because the model lines are based on a variety of very different and at other times very similar frames. Trying to be certain if two frames are the same based on catalog copies rather than live comparison is a fool’s work but it does make for interesting conjecture.
Serial numbers are also in question because I have two sources to look at and they only back each other up to some degree.
I’ll stick with the red frame being from 1938 mainly based on the serial number. The pattern and number are not consistent with what is thought to be appropriate for a 1936 frame. It also seems from real life examples that Schwinn produced some frame patterns longer than they were shown in the consumer catalogs.
Regarding the pattern of this frame with the large tank aperture, curved seat stays, straight chain stays and down tube, it does look virtually the same as a catalog cut for the 1936 B107 Motorbike. In 1937 that model (and similar unequipped B models) migrated to a frame with a curved down tube and curved chain stays which was used on the top of the line 1936 SA model (Autocycle). The C model frames for 1936 were similar to B frames but have a noticeably smaller tank aperture for a smaller tank.
The 37 frame lineup and model designations are confusing in that the new fully streamlined frames and the older pattern rectilinear frame both existed in the new top of the line BA series while the C models as a whole remained as they were in 1936.
Without covering all the frames produced in 1938, I noticed that the SA207, the BA407, the BA107, and the BA97 appear to use a continuation of the fully streamlined SA frame from 1936-1938. The BC97 and several other frames still seem to be based on the earlier C frames.
Now for the pay-off….
The 1938 BC117 appears to be a curved seat stay, straight chain stay, straight down tube frame. It is sporting a new “BC” type tank and the tank aperture appears large like the one for a standard “B” straight bar tank. It is also noticeably different from the BC no-tank version for the larger aperture, the closer proximity of the top tube and straight-bar at the seat juncture. Based on the serial number and the geometry of the red frame I believe it may be from a 1938 BC117.
I won’t be back in front of my serial numbers until Monday and I’ll see what I can find on the Cycle Truck then.
