I have been thinking about building up a tubular wheel, and it occurred to me that, because the tire bed diameter of tubular tires has to be the same (unlike clinchers where the tube can expand to fill a 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 like Spocalc to calculate spoke length on vitage tubular rims. About all 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 era, because the 'aero craze' had not arrived, and most rims were about 15mm tall, more or less?
So if you take an ERD of 622 mm, and intend to have the spoke tip seat 3 mm below the tire bed, then you could use 616mm for ERD for just about 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 roughly 16 spoke sizes?
TUBULAR WHEEL SPOKE LENGTH
Small Flange Large Flange Front Rear Front eRear 1-cross 2-cross 3-cross 4-cross
- Don Gillies
San Diego, CA, USA