The earlier Stronglight 49D cranks are quite a bit more slender and also have a more rounded profile than later ones. Alumninium 49Ds were introduced about 1937-8 - they are in the 1938 Constrictor catalogue. I have a pre-war British pair that are stamped Conloy, the trademark of Constrictor. Constrictor did not import them into England post WWII, Fonteyn started importing them again c1950. They were made until about 1985; until about 1983 they used a unique to Stronglight 22.2mm extractor thread size.
Hilary Stone, Bristol, England Summer appears to have now arrived with three continuous sunny days
David Bilenkey wrote:
> What makes these cranks:
>
> http://cgi.ebay.ca/
>
> an "old type"? What are the different features/details of the various
> generations of these? What was the total range (years) that 49D cranks were
> in production?