I am converting an old DT shifter frame to a STI bike and need to know which cable stops I need, I know i need barrel adjuster ones, but do I need concave or flat?

Its for a 1985 Peugot road bike with braze on shifter bosses.

Thanks

If you have classic (Campy style) bosses with a square base, then the adapters that both Shimino and campagnolo used to supply with their lever sets are what you need.

The type of base relates to how the bosses are fixed to the frame.

Classic bosses where the square based boss is brazed directly to the steel tubing use the curve back adapters to meet the curvature of the tubing.

the bosses typically riveted to aluminum and some carbon frames usually have a raised circular pedestal or platform between the boss and the frame. These call for the flat backed adapter to meet the flat surface surrounding the boss itself.