I ride to work on a 1993 Cannondale H 400 two days a week. As of late, the rear trigger shifter when shifting to a larger gear (is that up or down), has not been 100%. What I mean is that I now have to shift it twice to get the derailleur to move. The first time, I get nothing and then it catches on the second try. Is my trigger shifter wearing out? Where would one get a replacement? These shifters have a long throw and no click like new ones do. If I replace it can I get one with clicks and a short throw or should I use a true replacement and get just what I got.