I am currently using a campy 8 speed racing T RD and chorus 8 speed ergo with a shimano 12-26 8 speed rear cassette (with wheels mfg spacer kit) and triple front chainring 26-36-46 on my touring bike. I cracked my triple cranks and have a 110BCD double to replace them. I have a 34 and 48 chainring and am wondering what is the max rear cassette I can use with this setup. I would like a 12-29. Is that possible with the racing triple RD? Can I use a new 9-10 speed campy long cage chorus veloce etc to replace the 8 speed racing triple RD if I need to?

I'll go out on a limb and say I'd think it's probable that the derailleur could handle it, perhaps with a bit of tweaking required--I'm running an 8sp XT 12-28 with a regular short-cage Chorus 8v derailleur, and it works fine. Correct me if I'm wrong, but isn't the 12-29 only available in 10v? Seems to me like you'd be better off getting a new triple, as opposed to dealing with the bottom bracket issues involved in going from a triple to a double, not to mention the shifter complications.

Yes, you are correct. But finding the right triple has been problematic. I was using a topline set and getting one similar has been dificult. I have settled on the compact double that I already have and will make it work. Seemed like any new triple that I could find was going to require a new BB anyway. I have the compact double so I will use it for now. I do need to get a new BB but I can use a square taper so the price should be low. Don't know about the 12-29 but you are probably correct. This is an old paramountain (schwinn) bike with a funky BB so this whole process is a bit difficult. I would love to toss the whole thing and get a new one.

I assume by "requiring a new BB" for a new triple, you mean something like ISIS or Octalink? Sugino makes a fine square-taper triple (XD600), that's not at all spendy--somthing like $70 at alfred e. bike. Not sure about compatibility with your existing BB (someone in another thread was mentioning how some older Schwinn stuff doesn't play well with others), and I realize you're looking to use the double--just thought I'd throw this out there.