Weren't the hollow armed steel cottered cranks just as light as Al alloy cotterless? I hefted a '50s Durax (?) octagonal armed crank and although I didn't weigh it, it felt about the same as Al alloy Campagnolo Record cranks to me weight wise.
Kurt Sperry Bellingham WA USA
On 4/20/07, Chuck Schmidt <chuckschmidt@earthlink.net> wrote:
>
> This appeared on the iBOB list yesterday and I thought this might be
> an interesting subject for discussion on the CR list. Anyone want to
> add their comments?
>
> On Apr 20, 2007, at 7:22 AM, Jan Heine wrote:
> > More importantly, we (Bicycle Quarterly) put the history in
> > perspective. Many of our readers don't care when a logo on a crank
> > was changed, but they are fascinated by finding out why old bikes
> > were designed in certain ways and what we can learn from that. For
> > example, why did racers continue to use heavier steel cranks for
> > almost 25 years after the Stronglights were introduced? In various
> > web forums, you read that it was because the racers feared that the
> > aluminum cranks broke. BQ showed that many racers in the early
> > 1950s used aluminum cranks in mountain stages - if they were afraid
> > of failure, they would not have used them on stages where cranks
> > suffer from the highest loads. However, these racers switched to
> > steel cranks for flat stages. Combined with other evidence, we
> > concluded that on the flats, where weight matters little, the
> > racers preferred the lower tread (Q factor) of the steel cranks. In
> > the mountains, they were willing to pedal with their feet apart in
> > exchange for almost a pound less in weight. Suddenly, you realize
> > that there was a method behind this, rather than just "racers
> > always are conservative." And of course, it illustrates that racers
> > believed tread (Q factor) was very important, something that many
> > people still believe today, even though many crank manufacturers
> > don't care about tread at all.
>
>
> Jan writes, "BQ (Bicycle Quarterly) showed that many racers in the
> early 1950s used aluminum cranks in mountain stages - if they were
> afraid of failure, they would not have used them on stages where
> cranks suffer from the highest loads. However, these racers switched
> to steel cranks for flat stages."
>
> Aluminum cranks were first used by professional racers in the early
> '50s on mountain stages because of their light weight. Even though
> aluminum cranks were introduced in the mid 1930s, pro racers were too
> conservative to try them since they were new and unproven. Also
> aluminum's lack of a fatigue limit was well known (aluminum bike
> frames date back before 1900), so what better reason not to use
> aluminum cranks on flat stages since weight wasn't an issue on the
> flats. Also bear in mind that WWII interrupted the 25 years that it
> took pro racers to ride with aluminum cranks (no racing of any
> significance for the ten years between 1939 and 1948).
>
> Jan writes, "Combined with other evidence, we (Bicycle Quarterly)
> concluded that on the flats, where weight matters little, the racers
> preferred the lower tread (Q factor) of the steel cranks."
>
> I think what the pro racers preferred was the piece of mind of racing
> on their race proven steel cranks. In all my reading and talking to
> geezers that raced I have never once heard a concern for the
> different tread dimension (Q factor) of steel and aluminum cranks. I
> think your conclusion that racers didn't use aluminum cranks because
> the tread dimension was slightly wider, not because they didn't trust
> them, is highly suspect given the overall conservative nature of pro
> racing back in the thirties and forties.
>
> Incidentally I measured the distance the pedals are moved outwards,
> comparing a 1950 Bianchi Folgorissima equipped with steel Magistroni
> cranks and a 1979 Bianchi Superleggera equipped with aluminum
> Campagnolo Super Record cranks: it's a pretty insignificant 8.5mm on
> each side!
>
> Chuck Schmidt
> South Pasadena, CA