Re: [CR]Grand Bois Rims

Example: Framebuilding:Technology
Date: Tue, 16 Dec 2008 08:51:12 -0800 (PST)
From: "Fred Rednor" <>
Subject: Re: [CR]Grand Bois Rims
In-Reply-To: <>

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...

--- On Tue, 12/16/08, John Betmanis wrote:

> From: John Betmanis <>

\r?\n> Subject: Re: [CR]Grand Bois Rims

\r?\n> To:

\r?\n> Date: Tuesday, December 16, 2008, 11:18 AM

\r?\n> At 08:23 AM 16/12/2008 -0600,

\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> >

\r?\n> >

\r?\n> >

\r?\n> >

\r?\n> >Any reason to not have a hook bead rim?


\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> John Betmanis

\r?\n> Woodstock, Ontario

\r?\n> Canada