Re: Hey, Jobst, on p39 of The Bicycle Wheel the graph appears to show the ?impossibility of...

Michael Press wrote:
In article <7474d38d-9270-43ba-92c6-9dc0dd3add12@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,
Andre Jute <fiultra1@xxxxxxxxx> wrote:

On Sep 11, 9:50 am, Michael Press <rub...@xxxxxxxxxxx> wrote:
In article

Delineate the question. Precision, accuracy, clarity, completeness.
Absolutely. Couldn't agree more. Let's try again:
"Hey, Jobst, on p39 of The Bicycle Wheel the graph appears to show the
impossibility of a spoke being compressed. Is this
a) a misreading of your graph,
b) an error by the illustrator Sherry Sheffield,
c) a misrepresentation of the true data calculated,
d) an error in the formula you worked with, or
e) simply a boo-boo by you-you yes you?"

What exactly in _The_Bicycle_Wheel_ do you find
does not conform with your conception of a spoked bicycle wheel.
The impossibility of a bicycle spoke compressing as shown on p39 of
The Bicycle Wheel where the graph appears indeed to show the
impossibility of a spoke being compressed, precisely as I said in the
first sentence, and the headline of this thread.

Part of the problem is in the ambiguity of the phrasing of your charge. It can be interpreted in at least two ways:

The graph shows (proves) the impossibility of compressing a spoke.

The graph shows an impossible situation, that of a spoke under compression.

It seems you meant the latter, while some read your meaning as the former.

It's a judgment call to explicitly indicate the impossibility of typical bike spokes to support absolute compressive loads or not. He could have simply dashed the curve under the X axis*. On the other hand, that may have been a bit condescending since it points out the obvious. In any case, it's a nit.

*I'd argue against clipping the curve to the X axis in that information would be lost. That information describes the compression on a spoke that could support loading in that mode, not an entirely academic question given Mavic's new "technology":

"Tracomp

By creating a tubular carbon spoke using unidirectional fiber that can't be stretched neither compressed and by fixing it securely on both sides to the hub and the rim, we have brought a new concept of spoke work: it resists not only in traction but in compression too."
.

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