I am in the process of retrofitting my Schwinn Circuit with Ultegra components. My question is about the bottom bracket shell and routing the shifting cables. The bike that I am pulling the components from has what looks like a plastic guide for the cables. But on the schwinn, there are just two loops, which I assume the cables run through. Is there supposed to be anything else down there, or is that just it?
thanks for any help

Probably was nothing in there originally. When I do a bike like that I usually put a short piece of delrin or other plastic cable lining. Roger

The cables on my '87 Waterford-built Paramount just run through brazed on guides with capture loops, while my new Waterford has a separate plastic guide with capture loops screwed to the BB shell with a machine screw.

I agree with Roger that a couple of inches of delrin or teflon tubing to prevent the cable from metal to metal wear would be a good idea.