Historically riders and manufacturers considered Q-factor (what they called tread) to be important back in the 1890s... However I have not seen any reference since to anything to do with Q-factor in the cycling press until the late 1980s. I have hundreds of copies of technical articles from Cycling magazine and the CTC Gazette from 1900 to the 1960s. It is undoubtedly true that steel cottered cranks nearly always have a narrower Q-factor than cotterless cranks. Steel cotterless cranks are very rare (the Stronglight 49A is almost certainly the most common and it is a rare crank...). But I am almost certain that 49As have an identical Q-factor to 49Ds and in any case the Q-factor of 49D, 57/63, TA and Campagnolo Record are all low compared to later cranks from the major manufacturers in the 1980s and 1990s. I think, if riders had been at all concerned about Q-factor, there would have been some evidence in contemporary literature. There is lots of talk and discussion on the necessity for frame stiffness in literature from the 1900s onwards. More recent research from the 1980s shows that frame stiffness plays an insignificant part in power losses. Frame stiffness is important for steering precision but flexible frames do not slow a rider down due to power lost because of frame deflection. The importance of the 1980s research is still lost on riders, so strong is the myth, that a stiff frame is faster... I think this strongly suggests that the reason riders stuck with steel cranks was that the riders were conservative and preferred the known to the unknown. The reliability of steel cranks was known, aluminium cranks were less predictable in their reliability. Special equipment - special wheels, cranks, frames etc were saved for the most important stages. It seems that riders have always taken the biggest chances on mountain and time trial stages where performance gains might be most important. I am not sure of the details but I believe a Barra aluminium frame was ridden on mountainous stages of a TDF in the early 50s and of course Ocana rode a Speedwell titanium frame on mountainous stages in a TDF in the early 70s. Racers are not always the most logical in their approach. Using ultra light frames on mountain stages where they are most likely to break is not strictly logical...
Hilary Stone, Bristol, England
The Maaslands wrote:
> Chuck brought up the following:
>
> 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.
>
> I agree with Chuck that to make such a claim shows a decided lack of
> rigor in research and a highly questionable conclusion. You need say
> nothing more that if reduction of the Q factor was in any way important,
> track bikes would not have seen the rear hub widths increase from 110 to
> 120 on the rear with accompanying increase in the q factor (BB shells
> went from 65 to to 70 mm). You would also not have seen Italian BB shell
> widths go from 70 to 74, nor for that matter would anybody use 70 mm
> widths if 68 mm widths were equally functional. This whole q factor
> question is simply a way for manufacturers to differentiate their
> products to consumers. Lastly, looking at different pedals that I have
> fitted to bikes in my garage, I can measure at least a 8 mm difference
> between the 'narrowest' and 'widest'.
>
> Perhaps in 20 years BQ will be writing that many of the riders of the
> pro peloton in the early years of the new millenia continued to ride
> alloy cranks instead of carbon cranks because of q factor or other such
> reason... instead of the fact that they cost the teams less, were
> available in a greater choice of sizes and gave a performance more in
> keeping with the rider's expectations.
>
> Steven Maasland
> Moorestown, NJ
> USA