I have a problem with my wife's bike; 2007 Trek 1000 w/Sora brifters, approx. 300 miles on the bike. When attempting to shift from the granny to the middle ring, the shifter has "jammed" on many occasions, as in it won't move at all. It's stuck. A gentle tug on the derailleur cable produces a "click" in the shifter, as if it's ratcheting, and then it will function again, but it invariably happens again. I've fiddled with the cable tension but it hasn't eliminated the problem. My wife is still new to the scene and gets very frustrated/panicky when it happens and I'd like to ease her mind. Any thoughts would be appreciated.
Thanks -- Eric