Quote Originally Posted by OakLeaf View Post
Generally, most bikes with both front and rear derailleurs, because of the way the chain moves side to side.

It depends somewhat on your setup. The longer your chainstays, for example, the less the angle of the chain to the FD cage will vary. I rarely need to trim when I've got everything in just-so adjustment, but I think I'm in the minority there.

Thanks! I had vaguely heard something about trimming but really didn't understand what/how/why. Of course it didn't help that the RD had apparently been bumped out of position - but he fixed that as well. Education and tweaking, all at no extra charge