I have a QR Tri bike ultegra gear set. When I am in either the highest or lowest gear on the rear derailiur and try to switch to the next gear nothing happens for the first shift. I shift again and everything is ok, I can move up or down and get all the gears. So when my shifter is in either the extreme high or low position there is one shift that does nothing then the next shift is ok. I have taken up any slack in the cable and done as much as I know. Any thoughts?
Robert
Have you adjusted the H/L the screws? It sounds like they may be both too far out.
Have you looked at the Park Tool Co website (http://www.parktool.com/blog/repair-help/categories/derailleur-systems) yet?
Thanks I think that might be it
.
Check out some youtube videos. There are a bunch of very good ones done by bike stores which go over all bike stuff, including adjusting the rear derailer.