| Also known as | D637 |
| Diagram | Fig. 20 — REAR WHEEL · ref 40 |
| Subsystem | wheels |
| Listed in parts books | 1967–1970 |
Speedometer gearbox
Speedometer gearbox for the rear hub, drives the speedo cable off wheel rotation on QD rear wheel setups.
This is the speedometer gearbox, the little drive unit that lives at the rear hub and turns the mechanical motion of the wheel into the signal that spins your speedometer needle. It's a quickly-detachable-wheel setup part, and the catalog places it in the rear wheel figures, so this is the drive gear that sits in the QD hub itself rather than anything at the front wheel or gearbox top.
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The factory number on this one is 60-0637, and it carries forward from the earlier Smiths part BG5330/168 - if your parts book or an old invoice lists that number, it's the same physical piece. It also shows up under the alias D637 in some records.
Our catalog data ties this to rear wheel and QD rear wheel figures across appearances from 1967 to 1970. We don't have specific model-year fitment beyond that in our own records, so if you're matching this to a particular bike, give us a call and we'll confirm before you order.
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