Re: [CR]measuring chainstay length

(Example: Production Builders:Teledyne)

To: classicrendezvous@bikelist.org
Date: Thu, 12 Aug 2004 11:45:47 -0400
Subject: Re: [CR]measuring chainstay length
From: "Richard M Sachs" <richardsachs@juno.com>


snipped: "What is the value of measuring parallel to the ground?"

you can measure it anyway you want, but before it's measured, it's made. typically, the blueprints and fixture setups are oriented in a 2D format. for as many order forms that use this same schematic as casati - mine does, too - others use lines that are on the ground, emanating from the bb point to the rear axle point. e-RICHIE chester, ct

On Thu, 12 Aug 2004 11:25:48 -0400 marcus.e.helman@gm.com writes:
> This exchange has been a bit like the old Abbott and Costello "Who's
> on
> first?" routine.
>
> I am surprised to hear that chainstay length is measured parallel to
> the
> ground. As a number of correspondents noted, this is not really
> chainstay
> length at all, but rather the length of the leg of a right triangle.
> Why
> wouldn't the chainstay length measurement be the actual length of
> the
> chainstay (assuming everyone could agree on the location of the
> endpoints)?
>
> Obviously everyone can measure the way they want. What is the value
> of
> measuring parallel to the ground?
>
> This parallel to the ground business is not universal. Here is a
> page from
> Mark Bulgier's scans that suggests that some builders measure along
> the
> chainstay.
>
> http://bulgier.net/pics/bike/Catalogs/casati2/4.jpg
>
> Of course this could just be an easy explanation for the slightly
> educated
> customer. As Don Ferris noted:
>
> "Joe - When I talk about chainstay length to customers or regular
> bike
> folk,
> I'm talking about a straight line measurement from BB center to axle
> center
> (parallel). But when figuring chainstay length for rider balance on
> the
> bike or axle placement relative to the hanger eye, I'm talking about
> a true
> horizontal measurement, i.e., parallel to the ground. So yeah, the
> 6-9
> would be a horizontal measurement, not a parallel one."
>
>
> BTW, a brief look at some of the catalogs reveals that the rear axle
> is
> usually placed forward of the upper pivot bolt of the derailleur; in
> some
> cases, all the way forward.
>
> Marcus Helman
> Huntington Woods, MI