[CR]Hook bead tires

Date: Tue, 16 Dec 2008 15:26:45 -0500
To: classicrendezvous@bikelist.org
From: "John Betmanis" <johnb@oxford.net>
In-Reply-To: <a06230948c56d9f082311@[192.168.1.34]>
References: <<20853585.4355.1229437396725.JavaMail.root@vms073.mailsrvcs.net> <20853585.4355.1229437396725.JavaMail.root@vms073.mailsrvcs.net>
Subject: [CR]Hook bead tires

At 10:08 AM 16/12/2008 -0800, Jan Heine wrote:
>>http://www.vintagebicyclepress.com/componentoffer.html
>>
>>
>>
>>Any reason to not have a hook bead rim?
>
>The Grand Bois rims do have a hook bead, even though it is hard to
>see in the photo.

Okay, so what, exactly constitutes a "hook bead" rim, or at least one that is called that? Is a slight bump in the cross section all that's needed and how pronounced does it have to be? Does a 0.010" ridge qualify? I have several rims with such a ridge, but it's nowhere near as deep as what you see in illustrations and certainly not a "hook". Here is a typical illustration of a hook bead rim, http://www.sheldonbrown.com/images/bead-seat-diameter.jpg but the rims I have have nowhere near the "hook" shown there.

John Betmanis
Woodstock, Ontario
Canada