Ok, here's what I what to do, and I think I have it figured out, but I thought I'd check with better minds than mine. I want to get or build a tubular wheelset that I can use for cyclocross racing (tubulars are the shiznit for that purpose) and also use as a summer lightweight wheelset on my road bike. Cyclocross racing happens in the fall, and the road riding I'd use the wheels for is in the late spring and summer so no conflict.

Anyways my road bike is Campy Ergo 9-speed so I want the wheelset to have a Campy 9 (same as 10/11) speed freehub.

My 'cross bike is currently Shimanoish. I'm running an 8-speed cassette with an Ultegra RD and shifting it with a Suntour XC-pro 8-speed thumbshifter (the best thumbie ever made). Even though I'm mixing brands there, the shifting works fine, the indexing is close enough. I'd like to keep this setup, because it works and I like it, and also so that the current clincher wheelset can be my pit wheels and also usable for riding in the offseason.

Ok so that means creating a cassette with Campy cogs that is spaced to Shimano 8-speed right? A Campy 8-speed cassette would be pretty close to start with, but that won't work because Campy 8-speed cogs do not mate with Campy 9-speed or newer freehubs. Consulting Sheldon, what I think I could do is take 8 of 9 Campy 9-speed cogs and space them a little further apart. To get to 4.8mm cog spacing, the spacers would need to be 3.05mm. Spacers that size don't exist and I doubt could be easily created. However Campy 8-speed spacers are 3.1mm which I'm betting is close enough, especially since I'm using a Suntour 8-speed shifter which supposedly shifts the first 3 shifts at 4.8mm and the last 4 at 5.0mm?

All all spacers the same diameter? I.e are they just round rings that will fit onto any freehub? I'm assuming I can get a loose cog 9-speed Campy cassette. Spiders will prevent me from adjusting the spacing. I guess the smaller cogs might have built in spacers. Wheels mfg sells spacers, including 0.3mm, adding those to a 9-speed spacer, or cog with a built in 2.8mm spacer, would get me to 3.1mm total spacing. I would probably leave off the smallest cog of a 13-26 9-speed cassette to get a 14-26 8-speed cog set for cyclocross.

Whew - that was complicated, but I hope makes sense. Or does it? Thanks