Re: [CR]Re: measuring stay lengths

(Example: History)

Date: Wed, 11 Aug 2004 14:02:04 -0700 (PDT)
From: "Joe Starck" <>
Subject: Re: [CR]Re: measuring stay lengths
In-Reply-To: <>

-- Richard M Sachs <> wrote:

"my way of measuring (measuring along the centerline of the frame's central plane) yields the half cm diff that you note, not the 1 ephgrave mm that you not after the fact. "


Let's consider a 42 cm chainstay length and 8 cm drop.

Side view of the frame:

The designated chainstay length is 42 cm measured from center of bottom bracket to center of rear axle, PARALLEL TO THE GROUND, and the rear axle position is achieved by default on a vertical dropout, whereas with the use of a horizontal, it's anywhere the builder prescribes, in my case, it was always to the midway position that the axle could be positioned in the dropout, using primarily 1010B or shorter horizontals (Is this within Don's 6-9 mm axle/hanger edict?)

Now then, this above set-up on a frame jig means that the measurement along the somewhat centerline of the chainstay, I say "somewhat because the dropout center is 'neath it, measured from center of BB to center of axle position, should be set at a bit less than 42.7 mm, being the hypotenuse of the 42 cm leg of the triangle.

So, say 6 mm difference there.

Now then,

Top view of the frame:

Same 42 mm length, and yet the hypotenuse leg is a wee bit shorter, by about one millimeter. And when measured from outside of crank bolt to outside of skewer the differnce is less, as the measurement is now close to being parallel to the plane of the main triangle. But who cares about the top view, right? It was this dimension I was thinking about when I stated the one ducky difference, and so I yes, I contradicted myself , but in err' only. My bad.

Still, I would think that if a Sachs owner (Is Richard Cielec a Sachs owner?) were to measure his chainstay length from outside of crank bolt to outside of skewer, center to center, and came up with 42.5 on an 8 cm or so BB-drop-designed frame of yours, subtracted 5mm netting 42 cm, he has indeed measured his chainstay length quite nicely and precisely.

Starck, Joe

__________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard.