Re: [CR] dumb design, was A tale of two hubs?

(Example: Production Builders:Cinelli:Laser)

Date: Tue, 04 Jan 2011 09:13:18 +0000
From: "M-gineering" <>
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Subject: Re: [CR] dumb design, was A tale of two hubs?

On 1/4/2011 1:46 AM, John Betmanis wrote:
> Here is a pair of unknown hubs I bought off eBay a couple of years ago,
> described as "vintage".
> I got them for a 1951 Claud Butler I'm building and the widths are
> pretty close to what the frame is. If the rear hub is a poor design,
> should I substitute a more conventional modern one? This is a budget
> project, so I'm not striving for exact originality, just something that
> looks close.

they look fairly symmetrical to me, so they will be alright. The problem with rearhubs where one flange is much farther out from the centreline than the other is that:

-the spokes with the best bracing angle need a minimum tension to prevent them from breaking -the spokes with the worst bracing angle need a much higher tension to balance the sideways tension of the complimentary spokes , which kills the rim

Or the rim lives, and the undertensioned lh spokes keep breaking and loosening

The difference in tension is roughly proportional to the distances from the flanges to the centerline

Modern rims are designed for heavier dished wheels, and thus heavier than the classic rims designed for more balanced designs

Spocalc.xls (Damon Rinard/ Sheldon Brown) will give you the ratios and the angles

-- mvg

Marten Gerritsen
Kiel Windeweer