I definitely cannot re-space the bottom bracket cups with a cassette sprocket spacer inside of the DS cup, because it would pull the NDS cup too far in for the lock ring. So I want to keep that stuff as-is.

Fortunately, it looks like I'll be able to. I think I have lucked up with some parts. I scored a pair of 105 derailers that look nice on this bike. The yellow "105" on the RD matches my yellow outer cable housing. It's an FD-5504 and an RD-5500. The FD looks to be designed for a triple, as it has a fairly large cage with lots of shifting contours in it. My chain sits in the lower sections of the cage on the small ring, where the cage is pretty narrow, and it looks like I'll have to trim it with every couple of RD shifts. The middle ring puts the chain up in the wider section of the cage. I know these are the types of compromises that I have to take when working with older equipment that doesn't really go together, and I'm okay with that. I don't have a cable guide yet, but shifting it by hand demonstrates to me that this will work just fine. It pulls the chain off the middle ring with a quickness.

The RD is nice, but the B-pivot spring seems rather weak. I had a 12-28 cassette on the hub and I couldn't adjust the B-pivot tight enough to keep the upper cage wheel out of the large sprocket. It was fine on the next smallest (a 24T), so I just rebuilt the cassette using that as the largest sprocket. It's now a 12-13-15-17-19-21-24, and all of the sprockets are from the same S/T family except for the 24, which is an E/G from an HG50 mountain group. The close spacing seems to shift GREAT, and the derailer stays out of the sprockets.

I bought an inexpensive Campy dual downtube cable guide on eBay today, so that should be in the mail soon. It seems that Campag and Shimano are the only ones to make a dual cable guide, and the Shimano ones were usually pretty pricey. I paid $20 delivered for a parts box of 5 cable guides (including the dual Campy that I wanted) plus about a dozen smaller chainstay-sized clamp-on cable guides. Once I get that, I should be able to complete this drivetrain project and have the bike ready for spring. I appreciate this discussion on chainline!


pug_cl_4 by jnjadcock, on Flickr


pug_cl_5 by jnjadcock, on Flickr


pug_cl_6 by jnjadcock, on Flickr