Re: [CR]Steel cranks, aluminum cranks...

(Example: Production Builders)

In-Reply-To: <75d04b480704211323m2fd87a2aiaf03ae9c849fd6d9@mail.gmail.com>
References: <5A90E8EB-FFFE-4CE3-8E46-EB510185CF60@earthlink.net>
From: "Chuck Schmidt" <chuckschmidt@earthlink.net>
Subject: Re: [CR]Steel cranks, aluminum cranks...
Date: Sat, 21 Apr 2007 13:32:20 -0700
To: CR RENDEZVOUS <classicrendezvous@bikelist.org>


I would be very surprised if that was the case, but of course, I'd have no way of knowing without actually weighing them. Perception is extremely imprecise...

I picked up a track bike at the Framebuilders show the other month that weighed a little over seven pounds (yes, complete bike) and it felt the same weight as a full water bottle, which of course it didn't.

Chuck Schmidt South Pasadena, CA

On Apr 21, 2007, at 1:23 PM, Kurt Sperry wrote:
> 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