John, I don't want to speak for Robert Broderick, who perhaps will reply himself, but perhaps I can clarify a bit. It seems that Robert was presenting the history of Stronglight "5-arm" cranks as contrasted to 3-arm cranks, which they made in both steel and alloy. From model 57 on, "5-arm" is in fact an accurate description. But for the 49 and 49D, you may be right that "5-arm" is a bit confusing.
The model 49 was similar to TA Cyclotourist, Nervar Sport and several others, and is sometimes called a "5-pin" crank, which may be a bit more descriptive. These cranks all had a 50.4 mm circle of 5 holes on the right crankarm, to which the outer chainring bolted. The inner, or middle and inner in the case of triples, chainring then bolted to the outer. So the "arms" on these models were actually part of the outer ring, not the crankarm itself. TA used a "6-arm" outer ring, while Stronglight and Nervar used a "5-arm" outer ring. But the 5 holes in all these crankarms were of the same diameter and the same circle, meaning you could use an outer ring from any of them with the crankarm from another.
I think most of the confusion surrounds only the first picture in Robert's article, which shows a "6-arm" outer chainring bolted to a "5-pin" model 49 crankarm. It is possible this is an early pre-49D model 49 ring I have never seen, but I am about 90% sure that the ring shown in the first photo is not a Stronglight, but in fact a TA. Specifically, I think it is a TA Criterium which was 152 BCD or thereabouts (152 where the inner ring attaches to the outer). So I do believe the first photo does not quite match the description, as the description mentions inner rings as small as 38T, while looking at the bolt circle in the photo where the inner ring attaches to the outer, this circle seems clearly too large for a 38T ring. If the rings are in fact TA Criterium as I believe, the smallest ring would have been 44 or maybe 43T.
It was not at all uncommon to see TA "6-arm" rings attached to Stronglight model 49/49D crankarms. In fact this was perhaps the preferred setup on French constructeur bikes for a couple of decades. One reason for this, I believe, was that TA rings were introduced a number of years before TA offered crankarms. Stronglight were often the preferred crankarms as they were light, durable and beautiful. The TA rings were preferred over Stronglight on touring bikes as TA Cyclotourist inner rings came at least as small as 28T, while Stronglight was limited to 38T as Robert noted. The TA Criterium rings in the photo however, with a 152 BCD, were intended for racing.
You are correct that the early model 99 had arms with a squarer crosssection, while Robert's photos show the later more rounded model 99 arms. One item that I don't believe Robert's article mentions is the change in about 1982 from Stronglight's unique 23.35 mm extractor thread to the now-standard 22.0 mm. At least three Stronglight models, 99, 104 and 105, and perhaps even the long-lived model 49, were made both before and after this change, so thay can be found with either thread. It is not that uncommon to find a used crank with arms mismatched for extractor thread, such that one needs two different extractors to remove the arms. Add to that the fact that all thes models appeared with both French and English pedal thread, and one can encounter some interesting combinations of mismatched arms on used cranks.
Regards,
Jerry Moos
Big Spring, Texas, USA
> From: John Hurley <JHurley@jdabrams.com>
\r?\n> Subject: [CR] Stronglight 57 v. 63
\r?\n> To: classicrendezvous@bikelist.org
\r?\n> Cc: kohl57@yahoo.com
\r?\n> Date: Thursday, January 21, 2010, 9:24 AM
\r?\n> Thanks for the link to the very
\r?\n> interesting article with photos.
\r?\n>
\r?\n> I was confused by the author's (Robert Broderick's)
\r?\n> description of the
\r?\n> Model 49 as a five arm crankset when the photo shows a
\r?\n> six-arm spider.
\r?\n> Then I realized that although the chainring in this
\r?\n> particular photo has
\r?\n> six arms, the crank arm itself has only five bolts, which I
\r?\n> suppose
\r?\n> makes it a 5-arm crank, though it doesn't really have much
\r?\n> in the way of
\r?\n> arms. The 5-bolt arm is attached to a six-arm
\r?\n> chainring resulting in a
\r?\n> look very much like the venerable TA crankset. Even
\r?\n> so, the photo and
\r?\n> the description don't agree in that the inner and outer
\r?\n> chainrings are
\r?\n> held together by six bolts, not five as described.
\r?\n> The photo almost
\r?\n> looks like the arm attaches to the inner chainring, with
\r?\n> the outer ring
\r?\n> being scabbed onto the inner. This is contrary to the
\r?\n> description, but
\r?\n> is probably just my mistaken impression of the photo.
\r?\n> Can anyone
\r?\n> confirm?
\r?\n>
\r?\n> Also the article did not mention of the early Model 99 with
\r?\n> the square
\r?\n> crank arm cross section, but this is a minor omission, I'm
\r?\n> sure.
\r?\n>
\r?\n> John Hurley
\r?\n> Austin, Texas, USA
\r?\n>
\r?\n> Date: Wed, 20 Jan 2010 18:26:40 -0800
\r?\n> From: "P.C. Kohler" <kohl57(AT)yahoo.com>
\r?\n> Subject: [CR] Stronglight 57 v. 63
\r?\n> <http://search.bikelist.org/query.asp?SearchString=%22Stronglight+57+v%2
\r?\n> E+63%22&SearchPrefix=%40msgsubject&SortBy=MsgDate%5Ba%5D>
\r?\n>
\r?\n>
\r?\n> Harvey and others with queries re. Stronglight cranks
\r?\n> should consult our
\r?\n>
\r?\n> own Robert Broderick's superb contribution on the subject
\r?\n> on the equally
\r?\n>
\r?\n> superb (and boy is it ever!) Classic Lightweights UK site:
\r?\n>
\r?\n> http://www.classiclightweights.co.uk/
\r?\n> p.html