| Diagram | Fig. 6 — SWINGING ARM AND SUSPENSION UNITS · ref 22 |
| Subsystem | wheels |
| Listed in parts books | 1969–1974 |
Self-locking nut
5/16 inch UNF self-locking nut with nylon insert, used across several assemblies on the bike including swinging arm and rear wheel hardware.
This is 14-1902, a 5/16 inch UNF self-locking nut with a nylon insert set into the crown of the threads. That insert grips the bolt threads and keeps the nut from backing off under vibration, which is why Triumph called this one out specifically rather than leaving it to a plain nut and a lock washer.
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In the parts books it shows up across a wide spread of figures - swinging arm and suspension, rear wheel, quickly detachable rear wheel, exhaust pipes and manifolds, and even electrical equipment - so this is one of those hardware items Triumph used all over the bike wherever a fastener needed to stay put. It turns up in catalog listings from 1969 through 1974.
Because it's a general-purpose locking nut used in a lot of different places, don't assume it's only for one job. Check the figure for the assembly you're actually working on to make sure 14-1902 is the nut called for there before you order.
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