Re: [CR]Campy cut-out hubs


Example: Framebuilding:Paint

Date: Sat, 09 Feb 2008 02:15:47 +1300
From: Wayne Davidson <wayne.collect@xtra.co.nz>
Cc: Classic Rendezvous <classicrendezvous@bikelist.org>
Subject: Re: [CR]Campy cut-out hubs
References: <117268.29159.qm@web55903.mail.re3.yahoo.com>
In-Reply-To: <117268.29159.qm@web55903.mail.re3.yahoo.com>


Hi all, well I've read these emails, interesting to say the least. I'm not a wheel builder, but I would have to say that if Kurt did actually manage to get a wheel built with a hub with no centre, which I really doubt cannot be done due to the forces of spoke tension action on a flange revolving on a bearing, I for one would not ride a bike with that wheel.

To ride those hubs with the centres machined, is just about as stupid as riding a bike with alloy brake centrebolts and alloy pedal spindles.

I will think in saying thou, that a tallented wheel builder could build a front wheel that had sealed bearings in the flanges and the bearings were held in the flanges with circlips, that would at least be buildable as far as I can work out in my head, weather I'd ride its would be a different story. thou i'd also reckon it would have to be radial spoked, as I can see how the offsetindex on the spoke hole could be held otherwise without a centre joining the flanges. I for one would look in awl at such a wheel on a show bike, sure would make people think outside the box.............regards wayne davidson Invers NZ...........

Tom Dalton wrote:
> Kurt wrote:
>
> Think about it. What loads does the front hubshell between the
> bearings actually have to bear? I'm thinking not a lot. The axle
> should actually be doing all the work, the hubshell just needs to keep
> the dirt out and the flanges indexed to each other, and there are
> already the spokes and rim to help.
>
> I wonder if one could completely saw out the center of the hubshell
> and have it still work fine?
>
> Kurt Sperry
> Bellingham WA
> USA
>
> Kurt,
>
> There is at least one load at play on a front hub, and at least two in the rear. Front and rear hub shells are subject to a compressive force from the tension of the oblique spokes pulling the flange toward the center. Evidently this is not enough to cause columnar failure of the barrel, even on this slotted example, but there is no way the center could be cut out entirely. In the case of a rear hub there is also a torsional stress. I recall a mechanic at Yellow Jersey in Madison, WI who laced a radial-both-sides rear, just for giggles, and sure enough the shell twisted. Now, with even one side tangental, I think the strain is greatly reduced and distributed up to the rim across to the other flange, rather that across the barrel, but there's still some torsion on the barrel.
>
> Braking force at the rim probably also has an effect, at least in an asymmetrical (rear) wheel... in theory.
>
> Tom Dalton
> Bethlehem, Pennsylvaia, USA