Don - I think that may be oversimplifying the problem. Tubulars have been used since very early days, and vary widely. Rims were of different heights, and some had eyelets, some need washers, and some don't. I have one set, on my 40s Claud Butler, that were made by Banfi and Canti, that have almost NO height. They are actually solid and have no braking surface at all. So the nipples stick out of the gluing surface a bit. But some others of that time, notably Conloys, were kind of roundish and deep. Wood rims usually have shallow indents and need long nipples to go all the way through, though some later ones, like the ones sold by Super Champion, have inset cups like their alloy rims. So best to measure effective rim diameter and put that into the equation. I have Bikealog which has the best spoke calculator in it, and it allows you to put in your own rim or hub if not in its very extensive database. If anyone needs a calculation I will try to help. (Oh god, now I am going to get swamped with requests!)
Message: 4 ate: Sun, 1 Nov 2009 14:39:59 -0800 rom: donald gillies <gillies@ece.ubc.ca> ubject: [CR] Spocalc : Not necessary for Vintage Tubular rims? o: <classicrendezvous@bikelist.org> essage-ID: <20091101223959.9CA87435CA@ssh-linux1.ece.ubc.ca> ontent-Type: text/plain I have been thinking about building up a tubular wheel, and it ccurred to me that, because the tire bed diameter of tubular tires as to be the same (unlike clinchers where the tube can expand to fill deep-V type of rim, rim-tape-length has to be essentially standard). If you are using short nipples, then, you shouldn't need a program ike Spocalc to calculate spoke length on vitage tubular rims. About ll you should need is (a) X-Cross-ed-ness, and (a) Flange Type Small, Medium, Large). You wouldn't need Rim height in the vintage ra, because the 'aero craze' had not arrived, and most rims were bout 15mm tall, more or less? So if you take an ERD of 622 mm, and intend to have the spoke tip seat mm below the tire bed, then you could use 616mm for ERD for just bout all tubular rims in the vintage era, couldn't you? Is this true? Do any of you have a chart on the wall somewhere with oughly 16 spoke sizes?
Bob Freeman
Elliott Bay Bicycles
2116 Western Ave
Seattle, WA 98121
206-441-8144
http://www.elliottbaybicycles.com
http://www.davidsonbicycles.com