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Old January 15th 20, 04:17 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Default Crochet vs hook-bead rims

On 1/14/2020 9:16 PM, AMuzi wrote:
On 1/14/2020 8:02 PM, Radey Shouman wrote:
"Mark J." writes:

On 1/14/2020 10:34 AM, AMuzi wrote:
On 1/14/2020 11:51 AM, jbeattie wrote:
On Tuesday, January 14, 2020 at 9:10:48 AM UTC-8, Mark J. wrote:
So I learned (?) something new (?) today reading Lennard Zinn's
column
at Velonews:
https://www.velonews.com/2020/01/tec...blowoff_503717



What I learned was the term "crochet-type rim".

Looking it up, some sources say this is just another name for
hook-bead,
BUT:

https://en.wikipedia.org/wiki/ISO_5775#Rims  ÂÂ* says:

    Both crochet (C) and hooked-bead (HB) rims have inner
profiles
    that curve inwards near the outside diameter of the rim to
    provide a hook that helps retain the tire bead under high
    pressure. On modern bikes crochet rims are most common and
    hooked bead rims are rare. The distinction is primarily that
    hooked-bead rims lack the defined bead seat of straight
side and
    hooked bead rims. The tire is held in position radially by
the
    hook without a bead seat playing a role. Without a bead seat,
    the primary designation of the diameter in terms of the bead
    seat is not applicable, and the governing diameter is the OD.

Sentence #3 pretty clearly has a typo, but I can't figure out the
correction, and I cannot find any images on google that directly
compare
hooked-bead and crocheted (also sometimes mis-named "crotched").

I suspect the "HB" in the quoted passage above is really referring
to an
obsolete design, and that the quoted writer would even call the 70's
Mavic Mod E "crocheted" rather than "hooked-bead," even though we all
called them hooked-bead.

Can anyone clear this up with an authoritative source?

Mark J.

I'm sure there must be an ISO drawing
somewhere. https://en.wikipedia.org/wiki/ISO_5775ÂÂ* My sense is that
we've been calling ISO "crochet" rims "hook bead" rims but that a
true "hook bead" looks like an open hook ala the old steel rim
design. http://www.asia.ru/images/target/pho.../Steel_Rim.jpg


Yes, that's correct.
Rims with a lip and also a bead seat, such as items #571 and #A125
he
http://www.yellowjersey.org/photosfr...t/WEINRIMS.JPG

are the modern standard design.


Thanks, Jay & Andrew.Â* SO I gather that in the quotation above the
author intended to say:

Â*Â*Â*Â*The distinction is primarily that
Â*Â*Â*Â* hooked-bead rims lack the defined bead seat of straight side and
Â*Â*Â*Â* /crochet/ rims.

Somehow, I think I'm just gonna keep calling them "hooked-bead." It's
worked for me for forty years.


Not that it makes a difference, but doesn't "crochet" just mean "hook"
in French?


Mais oui!
From 'crochet' rims to christening -584 tires as '27.5' to calling a
semi an 'assault weapon' to every statement ever released by the Federal
Reserve, an avoidance of clear language (or actual obfuscation) is
itself a telling point about the message. And the messenger.


Clipless pedals? (That one clips into?)
Clincher? (What does it clinch?)
Gears? (Aren't they really sprockets?)
Mountain bike? (Hardly ever used on actual mountains.)
Road bike? (When almost all bikes are almost always ridden on roads?)

--
- Frank Krygowski
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