Hi Gang,
Just my two cents contribution here: I have a 70's era Gran Sport triple on my Olmo everyday bike. The chainset is 27/44/52, and the freewheel 13-26. It took a bit of work with getting the chain length exactly right (with guidance from this list), but it now shifts this combination quite well. Given this spread, even a 39X28 double should be OK?
To move on, I have a C-Record rear derailleur that doesn't have a spring at the attachment pivot. Apparently this is an early generation C-Record part, as the one on my '89 Legnano does indeed have the spring.
The question is, do I set this up with a shorter than "normal" chain in order to keep the chain tensioned with the spring at the idler cage? I've tried assembling it with my standard starting point of 108 links, and the lower chain run sags. The fact that it sags like that suggests that I am off by a lot of links, not just a couple. I have a 39/52 chainset and a 13-26 freewheel on this, and am afraid that if I shorten the chain it will bind if (when!) I have the gears crossed.
The bike this is going onto, if it makes a difference, is the Masi 3V that Brian did such a lovely job of painting last spring. I've finally assembled all the bits to complete it. When I'm bored of riding the rollers (snowy up here north of Toronto!) I can lovingly fondle the pretty bits while I slowly assemble it.
Obviously spending too much time in the basement in Toronto,
Larry Strung
> To increase capacity of any rear derailleur one can go to a 11 teeth
> pulley from a 9 teeth pulley and set wheel further back in horizontal
> drop outs. That will get you a few teeth capacity on the rear cogs. Most
> Campagnolo rear derailleur can handle a 28 teeth cog but not as well as
> lower cogs.
> Charles Nighbor In rainy Walnut Creek, CA