I'm overhauling and putting lots of new parts on a buddy's Cannondale 3.0 that he was given by his brother. I replaced the dead STI shifters (I didn't have the patience to try and resurrect them) with indexed down-tube shifters, but am not sure how to mount the shift levers on the bike.
The frame does have down-tube lever bosses but they're different than what I've seen on steel frames in that they have a flat mounting base built in.
The problem here is that the shifter bosses have a plastic base that's built into their attachment to the frame. These do not allow the mounting of standard down-tube shifter base-pieces; standard ones are designed to match the curvature of the frame's down-tube, and in this case the already-installed (and permanently-installed) mounting base is flat.
However, the mounting base on the frame doesn't include the interface for the shift levers so that they can index.
Are there metal base-pieces with the correct flat backside to fit over the plastic base on the Cannondale? Alternately I could put the curved base-pieces on a grinder and flatten the back so they fit over the flat based on the Cannondale's shifter bosses. 'Cept that I don't have a grinder.
Here's some pictures to illustrate what's going on - I don't think I've described it all that well. I just want to get these shifters on the frame.