Lambert/Viscount Forks Are Failure-Prone

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Lambert and Viscount were two names for a bicycle maker in the 1970's. The bicycles came with a novel aluminum fork which sometimes failed, estimated at about one in a hundred bicycles.

Although the 1970's was a long time ago, lightly-used models with original forks still regularly show up for sale.

The following shows three fork models. Only two are known to be failure-prone.

The following article briefly describes three models of fork, two of which are known to be dangerous, and one which is not known to be dangerous.

Summarized:

The first Lambert fork, Figure 1, had an up-facing stub and the steer tube was attached by heating to expand, then pressing down on the crown. It was then pinned through holes going front-to-back.
The second Lambert fork, Figure 2, was similar but pinned through holes going side-to-side.
The third fork, Figure 3, was mostly used on Viscounts, and uses a threaded steel insert screwed in to the fork crown. This model is not known to be dangerous.

Various recent web pages note that only about 1% of forks were known to have broken — of about 30,000 bikes sold, 30 forks reportedly broke before the recall, with 12 injuries. However, this under-states the risk, since those forks failed within three(?) years of new, whereas the forks now are over 30 years old. Also, failures noted before the recall consist of only those failures reported, but likely there were also failures not reported.