Schwinn New Worlds: Rebuilding 1940s Cottered Crank Sets

I devoted part of this long weekend to Schwinn New World bicycles. I rode my 1947 New World to the local park on Friday and Saturday. The weather was warm Friday, but much cooler and more like November on Saturday.

Today I devoted to working on a 1940-41 New World. This bicycle came as a project to me as a core, stripped of most of its parts. It is unclear how this happened, but it is something I see with fair regularity. American road bikes from the early years often share some parts in common with balloon tire bikes. People sometimes strip the parts from the road bikes to add to the more valuable balloon tire bikes. We don't see this as often with English bicycles,  because the parts usually do not transfer from English bicycles to balloon tire cruisers.

In any event, the first tasks were to re-build the headset and to build a three piece bottom bracket for this project. The headset was not difficult to assemble from original and a few later (1950s-era) parts.

The bottom bracket was a harder nut to crack. Schwinn actually made its own three-piece bottom brackets in the 1940s. I got out the calipers and did some testing on a 1948 Schwinn Continental I have that is also a three piece crank bicycle.

The calipers revealed that Schwinn seems to have copied Birmingham Hercules parts from England. It turns out that 1940s Schwinn cranks, spindles, cups, and lock rings are all very close in measurement to Birmingham Hercules parts.

I bought 1940s Schwinn cranks and supplied my own Hercules adjustable cup, lock ring, and cotter pins. The pins required some filing, but not much.

I used .250 ball bearings (11 per side), the same as a Birmingham Hercules or a Nottingham Raleigh. The spindle came from an old Phillips bicycle. The fixed cup is the original Schwinn part, which was never removed from this bike.

Hopefully this mixed parts bottom bracket set up will work well. It fits together snugly and runs smoothly on the bike stand at least. The use of Schwinn cranks and a Schwinn chainring look good on this bicycle, while the use of quality English internal parts should allow it to run smoothly.