Re: [CR]Did the old racers use half-step gears?


Example: Framebuilders:Masi

In-Reply-To: <005401c43179$2af946c0$6400a8c0@jfbender>
References: <a05210611bcbc8a4d66c4@[66.167.140.138]>
Date: Mon, 3 May 2004 18:55:21 -0700
To: classicrendezvous@bikelist.org, Joe Bender-Zanoni <joebz@optonline.net>
From: Jan Heine <heine93@earthlink.net>
Subject: Re: [CR]Did the old racers use half-step gears?


Joe,

It seems that the Koblet example is not the exception, and the texts did not mention that he used something non-standard. In fact, they talked about something that was his "base gear" and how he had chosen one that was too high or too low (don't recall) for one stage. Also, the fact that the racers changed gearing almost every stage seems to indicate that they didn't use half-step. Half-step has the advantage of providing a relatively wide range of gears, with no need to customize it for the conditions.

I don't know any old racers who could help. The randonneurs used cross-over gearing back then, often a 48-32 front with a 14-22 or 14-24 rear. But of course, their derailleurs were able to handle those chainwheel differences. (I can imagine the racing derailleurs would have been designed to do so, too, if racers had demanded it. Chicken-and-egg, as usual.)

Anyhow, both the Koblet story of "base gear" and the fact that he does not appear to have been an exception seem to indicate that there is more to the story. -- Jan Heine, Seattle Editor/Publisher Vintage Bicycle Quarterly http://www.mindspring.com/~heine/bikesite/bikesite/
>Jan,
>
>Why is it a "myth"?
>
>These two examples seem like very custom setups for some special purpose. Is
>there evidence that examples like these were widespread?
>
>The box stock arrangement would be something like 49-52 chainwheels with a
>14-16-18-21-24 freewheel which is a classic half-step. My '59 Frejus came
>that way. Because the crossover gears really don't figure, any freewheel
>with 2 tooth or 3 tooth gaps in the middle 3 cogs yields a reasonable half
>step.
>
>It's hard to avoid a half step given small chainwheel differences unless you
>go to the erratic freewheel progressions provided in the Koblet examples.
>
>Joe Bender-Zanoni
>Great Notch, NJ
>----- Original Message -----
>From: "Jan Heine" <heine93@earthlink.net>
>To: <classicrendezvous@bikelist.org>
>Sent: Monday, May 03, 2004 8:04 PM
>Subject: [CR]Did the old racers use half-step gears?
>
>
>> An often-repeated myth is that racing bikes before 1950 used
>> half-step gearing. This is because the front chainrings often were
>> relatively close in size, as they are on a half-step set-up.
>>
>> However, both Koblet's bike in the 1951 Tour de France (see VBQ vol.
>> 2, No. 2), as well as the 1960 Olmo in the upcoming issue, show that
>> the gearing was far from half-step:
>>
>> Koblet used gears like 48x52 with a 14, 16, 17, 18, 19 freewheel or a
>> 48x50 with 14, 16, 18, 22, 24 or similar stuff.
>>
>> Charting the first gear ratios show a lot of duplication:
>>
>> 48 52
>> 14 93 100
>> 16 81 88
>> 17 76 83
>> 18 72 78
>> 19 68 74
>>
>> The Olmo, according to the original sales sheet, used a 48x51 with a
>> 13-26 freewheel. Assuming this was a 5-speed freewheel, the Olmo
>> charts to:
>>
>> 49 51
>> 13 100 106
>> 16 81 86
>> 19 68 72
>> 22 59 63
>> 26 50 53
>>
>> Toward the middle of the range, it is almost half-step, but the
>> chainrings really are too close in size. You get five pairs of gears
>> with big jumps in between. (Half-step means that all gears are evenly
>> spaced).
>>
>> Charting Koblet's gears shows it is even further from half-step, yet
>> they obviously spent lots of time thinking about their gears: Most
>> racers then used different sizes of chainrings almost for every
>> stage, much to the chagrin of the mechanics (which were provided by
>> the organizers back then).
>>
>> Also, the recently posted report from Jobst Brandt showed no evidence
>> of half-step gearing, as far as I could tell. (The fact that he
>> changed the freewheel ratios without changing chainrings indicates
>> that it cannot have been half-step, as the two are interrelated with
>> half-step: Chainring size difference must be half (in %) of freewheel
>> cog size differences.)
>>
>> So if it wasn't half-step, what was the reasoning behind those gears?
>> Anybody know? Maybe Jobst would know. Does anybody have a contact for
> > him?
>>
>> --
>> Jan Heine, Seattle
>> Editor/Publisher
>> Vintage Bicycle Quarterly
>> http://www.mindspring.com/~heine/bikesite/bikesite/
>> _______________________________________________
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