On Apr 14, 12:16 pm, wrote:
On 13 Apr 2007 19:56:50 -0700, "john" wrote:

On Apr 13, 1:00 pm, wrote:

[snip]

Here's some long-pitch block chain:

http://www.flickr.com/photo_zoom.gne...2139683&size=o

On the bottom run of chain, you can see the short, solid block that
connects the long-plate links. (A variant called double-roller chain
replaced the solid block with a pair of short links, but you can see
that the blocks here are solid.)

Note the tiny in-tension chain "stays" and in-tension down "tube"
common in antique frame designs.

[snip]

No, no, Carl! They are, not in tension! They stand in compression!
Now repeat after me, three times...

Dear John,

Lest the innocent be misled, here are some drawings from Sharp that
show some of the curious in-tension frames that were common before the
triumph of the modern double-diamond frame:

http://i11.tinypic.com/35mgrif.jpg

Click on the lower right for full-size in Explorer.

Cheers,

Carl Fogel

Of course, Carl
I actually agree that the down spokes do stand in compression.
You're probably aware of the "Sling Shot" bicycle that's made today
using a tension down tube.
www.slingshotbikes.com

Regards, John