In my experience, if you keep the pressure below 85psi (about 6 bar) the hook bead-seat is unnecessary. I believe hook beads were invented so that you could use very high inflation pressures with flexible (i.e. Kevlar)bead tires.
If the pressure isn't so high, the rim does not require a hooked bead-seat. With steel bead tires, I've even run 95psi (nearly 7 bar) without any problems.
Best regards,
Fred Rednor - Arlington, Virginia (USA) - and about to grab
a drink from the other kind of bar...
> From: John Betmanis <johnb@oxford.net>
\r?\n> Subject: Re: [CR]Grand Bois Rims
\r?\n> To: classicrendezvous@bikelist.org
\r?\n> Date: Tuesday, December 16, 2008, 11:18 AM
\r?\n> At 08:23 AM 16/12/2008 -0600, charliepedal@verizon.net
\r?\n> wrote:
\r?\n> >
\r?\n> >
\r?\n> >
\r?\n> >It looks like the Grand Bois Rims are not a hook bead
\r?\n> type?
\r?\n> >
\r?\n> >
\r?\n> >
\r?\n> >http://www.vintagebicyclepress.com/componentoffer.html
\r?\n> >
\r?\n> >
\r?\n> >
\r?\n> >Any reason to not have a hook bead rim?
\r?\n>
\r?\n> As I recall, hook bead rims were a relatively recent
\r?\n> invention, used for
\r?\n> folding tires with "stretchy" beads that would
\r?\n> otherwise blow off regular
\r?\n> straight sided rims. It seems that modern clincher bicycle
\r?\n> tires no longer
\r?\n> have strong wire beads, or their beads don't sit deep
\r?\n> enough, so that they
\r?\n> need hook bead rims to keep them in place. So to answer the
\r?\n> question, those
\r?\n> Grand Bois rims are probably of traditional vintage design
\r?\n> meant for
\r?\n> traditional vintage tires. Of course, this is all
\r?\n> conjecture on my part and
\r?\n> I'd like to know exactly how it came about that modern
\r?\n> clincher tires
\r?\n> degenerated to where they required hook bead rims to keep
\r?\n> them in place.
\r?\n>
\r?\n> John Betmanis
\r?\n> Woodstock, Ontario
\r?\n> Canada