Originally Posted by datlas

Interesting experience on today's ride. Recall I still run Ultegra 6700 on my bikes. Also recall that the exposed parts of the shifters are notorious for rusting, and there is a bit of rust on mine.

When I started the ride, my inner paddle (to shift to a smaller cog in back) would sometimes just move but not shift, and sometimes would "catch" and shift properly. Oh crap. The outer shifter would shift crisply to the bigger cogs nice and crisply. So I am pretty sure the problem is NOT a fraying cable or a cable problem at all, but something in the shifter mechanism that is not engaging properly. I am not enough of an expert on the shifter innards/mechanism to make a definite diagnosis. Luckily, as the ride progressed, the weak "catch" or inability to shift at all became less frequent, and within 15 minutes it was working fine.

My suspicion is that whatever ratchet or other gizmo inside the shifter may have gotten stuck due to rust and lack of use (this is my first ride on the bike in 2 weeks), but I am torn whether to just leave it alone versus spray a bunch of WD40 and/or lube up into the mechanism to help clear out whatever the cause was.

Suggestions???