kmart

I have a steel frame with downtube shifter bosses. I also have a 9-speed 105 group with STI shifters that I want to put on it, except I don't have the cable stops that attach to the shifter bosses. When searching on ebay, I've found that there are two kinds of cable stops: one with flat bottoms, and one with curved bottoms. So, which one will work better for my steel frame?

According to this page on ExcelSports, they say "Use flat with oversized and aero downtubes. Use round with most steel frames and aluminum frames with standard downtubes."

That part makes sense, but will the flatbottomed kind fit steel-downtubes as well? I know it wouldn't sit exactly flush, but will this be really obvious and will the stops wiggle around?

Retro Grouch 

The flat bottom ones will work but they'll look goofy. If it was my steel frame bike I'd hold out for the curvy ones.

Shimano has included a set of those down tube cable stops with every aftermarket set of STI levers for years. The upshot is that every LBS in the land probably has a drawer full of the things.

If they like you that might even be a gimmy.

kmart

The group is a takeoff from an aluminum frame that has integrated cable stops, so that's why I need to buy separate ones. I'll be sure to get the curve-bottomed ones.

Also, is that big lever on the rear-derailleur cable stop actually useful? My shift cables already have inline cable-tension adjusters right by the shift levers so I don't think I need these, but....?

Retro Grouch 

I've never found that lever to be very useful. I guess the idea was to make it easier to fine tune the rear derailleur from the saddle but who does that?

kmart

It's the kind of feature that is rarely used, but when you are first setting up the bike it's very handy. Tuning the shifters on a bike stand and tuning it while riding are two very different things. Generally, on the road tuning works best.

Anyways, I figured that tab was a bit of a gimmick. I'll just get the regular barrel-shaped kind. Thanks for the reply.

HillRider

I've used the barrel adjuster for the front derailleur to do an on-the-fly adjustment but never changed the rear derailleur downtube stop adjuster. BTW, some of Shimano lower line groups (RSX for one) had a plastic barrel adjuster on both dt stops.