Hi all:
My first 10-spd. had this derailleur, and I had to learn how to make it work. Later on I worked in a Schwinn bike shop where I assembled countless bikes with this same derailleur, and they all went out the door working just fine. Here's what one needs to do to make them work properly.
The Parallelogram pieces are held together with small bolts and nuts. One of the two pieces that each bolt goes through has a smooth hole and the other has threads. You have to adjust the bolt's tightness so that the two parts are neither too loose nor too tight, then tighten the nut (it's a locknut) against the piece with the threads. Sometimes it takes a couple of tries to get the tension just right. This locks the bolt in place so that the other piece can pivot freely and smoothly on the shank of the bolt. One must do this with every bolt and nut on the parallelogram. If you do not check them all you take the chance of one of the nuts being loose and eventually falling off. If there is any play or slop between the parallelogram pieces, it will allow the cage to pivot or twist sideways when you shift. After adjusting every nut and bolt, a drop of oil on each pivot will help it work even better.
Furthermore, if one of the parallelogram parts gets bent in any way it will prevent the derailleur from working properly. You also have to find the correct spring tension on the cage, there are usually two or three hooks on the cage for this, and usually only one setting really works good.
I think a lot of people were unable to figure this out, and other than the fact that they are cheap and heavy, that's why they don't like these derailleurs. I also think that these derailleurs work just fine for bikes like Schwinn put them on.
Most derailleurs don't require this amount of work, all you need to do is adjust the cable tension and the limit screws and you're off. I knew mechanics that had to be shown how to adjust these derailleurs, because they couldn't figure them out.
That's my 2-cents worth on this subject.
"Bicycle Mark" Perkins Fresno Cycling Club - Historian Fresno, California, U.S.A.
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