Originally Posted by
3alarmer
Note that frames originally equipped with a set of DT clamp on shifting levers usually has something braised to the down tube as a stop to prevent them shifting down the tube under use.
You might need to kludge something for this or you might not,depending on how well the clamp fits your tube and how hardthe pull is.
Even many cheap bikes with stem shifters had a "stop" brazed on the underside of the downtube to keep the band-on cable housing stop in place.