Re: [CR]FW: Fw: Story of me and my Legnano


Example: Events:Cirque du Cyclisme:2007
Date: Mon, 04 Feb 2002 21:44:28 -0800
From: "Bill Bryant" <Bill_Bryant@prodigy.net>
To: "Mark A. Perkins" <bicyclemark@juno.com>
Cc: classicrendezvous@bikelist.org
Subject: Re: [CR]FW: Fw: Story of me and my Legnano
References: <20020204.195206.-66857.10.bicyclemark@juno.com>


Hi Mark-- "Stack height" refers to the entire headset assembly. This measurement will let you cut the steerer tube to the correct length ~once~, something impossible to do if you only know the bottom assembly dimension. You could certainly build a frame & fork with just the crucial bottom dimension, but some subsequent measurement and cutting will be needed to finish the job--if you included enough steerer threads in the first place. OTOH, you don't want to have a steerer with too many threads; there should just be enough, but not so many that the stem's expander wedge distorts the wall of the tube already weakened by having threads cut into it. Obviously the modern Ahead-sets avoid all of this by not having any threads in the steerer, but now we're straying away from our CR zone.

Anyhoo, my early edition of Sutherland's breaks it down into helpful sections; I can only assume modern editions are the same: the lower assembly dimension = A; the upper assembly dimension = B; A + B = C, or the entire stack height.

BTW, Sutherland's also has a very useful quote from Confucius I love: "One measurement is worth a thousand expert opinions." ;-)

Bill Bryant Santa Cruz, CA

"Mark A. Perkins" wrote:
> Hello again everyone:
>
> Seeing all of these messages mentioning stack heights has brought to mind
> a question I have regarding this dimension.
>
> If you are referring to a listed measurment such as in a Sutherland's
> Manual (mine is in storage at present - several hundred miles away), does
> the measurement include the upper as well as the lower components of the
> headset? For it is only the lower components which will make a
> difference in the relationship between the fork crown and the bottom of
> the head-tube.
>
> When I designed each of the 5 frames that I have built, I had the headset
> before I began, and I measured only the lower components. This way I
> knew exactly how much space would be needed to use whichever headset was
> chosen. I'm not certain, but I believe the numbers I came up with were
> not the same as those listed in Sutherland's.
>
> I suspect that if these stack heights are listed somewhere, that they may
> be including the upper components. I do not remember how Sutherland's
> lists them, so I am asking. Anyone?
>
> "Bicycle Mark" Perkins
> Fresno Cycling Club - Historian
> Fresno, California, U.S.A.