| Diagram | Fig. 21 — FRONT WHEEL · ref 20 |
| Subsystem | wheels |
| Listed in parts books | 1969–1970, 1973–1974, 1976–1980 |
Nut - disc/sprocket bolt (3/8" UNF lf locking)
3/8 inch UNF self-locking nut used across front end, brake, and wheel fittings on these Triumphs.
14-1903 is a 3/8 inch UNF self-locking nut used in a handful of places across the front end and brake/wheel assemblies on these Triumphs. The nylon insert in the nut keeps it from backing off under vibration, which is why you'll find this style specified on fasteners that see a lot of road shock rather than a plain nut and washer.
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Across the catalog it turns up on fork parts and steering damper assemblies for the T100C, T100R, and TR6C, as well as in the handlebar and control lever fittings, front brake, front wheel, and rear brake figures. That spread tells you it's a general-purpose locking nut Triumph used wherever a 3/8 UNF stud or bolt needed to stay put - not a single dedicated part with one job.
If your parts book calls out a disc or sprocket bolt nut, a handlebar mounting nut, or a locking nut on the brake or wheel assemblies at 3/8 UNF, this is likely the one. Worth keeping a few on hand since they show up in more than one spot on the bike.
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