Stratman351

Last week I put a new Ultegra 11 -25T cassette (as part of a new wheel set) on my 2011 Felt Z5, which came with an 11-28T 105 cassette. I set the RD up just as I've been doing for years, set the hi limit, low limit etc. (the standard Park Tool/Sheldon Brown approach), and then adjusted the wire tension. Rode a few times totaling about 100 miles, with the bike shifting smoothing and quietly, basically perfect. Then, yesterday as I was riding, I suddenly couldn't get it to upshift, was basically limited to the 7 lowest gears. By fiddling back and forth with the brifter while I slowed my pedaling I could get the chain to jump down to the smaller sprockets, but not reliably.

Today I went to adjust it, and decided to start from scratch, i.e., adjusting the hi and low limits with the cable fully slack and then adjusting the cable tension. No matter how I set it, I couldn't get it to where it would shift to the largest sprocket while still being able to drop to the smallest sprocket and vice versa. Whenever I had it set so it would drop onto the smallest sprocket, I couldn't get it to shift back up to the largest sprocket using the brifter (and could barely do it even working the cable by hand; I couldn't take up enough slack without really stretching the cable). And I noticed it was taking (at least) two clicks to drop one sprocket as I moved past the 6th or 7th largest sprocket. While I was doing this, trying to count clicks, the brifter stopped clicking - I could feel it lose the indexing - and when I gave the cable a tug with my fingers, it began to pull right out of the brifter.

So, given the symptoms I was having BEFORE the cable pulled loose from the brifter, is it likely the shifter was broken (or broken now)? Other thoughts on the problem? The bike has been trouble-free since I got it last June, have about 3,500 miles on it. The Ultegra cassette shows as compatible with the Shimano 105 5700 RD that's on the bike, and I can't see anything wrong with the RD (everything is lubed and working smoothly).

FD is adjusted perfectly, no problems.

SEAtrain

Try focusing on the brifter only. I'd loosen the cable anchor and try sequencing the brifter through the gears both directions. Does it click into each position positively? When I've had problems, I noticed my brifter wouldn't engage or it felt really "mushy" instead of a positive click.

If the brifter seems OK, I'd return to cable tension. For me, 1.) I like to shift into the small front chain ring and largest gear in the rear (fewest # of teeth). 2.) I set the rear derailleur barrel adjuster so that is fully screwed into the derailleur. This gives me the best opportunity to increase cable tension after I anchor the cable. 3.) Take out the slack in the cable and tighten the cable anchor 6-7Nm. 4.) Try shifting into smaller gears in the rear (larger # of teeth). I usually hear drive train noise and most often need to adjust the rear derailleur barrel adjuster to increase cable tension.

Here is a link to the RD spec. Note the cable routing at the anchor.
https://www.shimano.com/media/techdoc...9830702204.PDF

turkey9186

Are you sure the cable end is seated properly inside the shifter?

Al1943

Also confirm that all of the cable was out of the shifter when the cable was attached to the derailleur. Flip the small shift lever several times while attempting to pull cable out of the shifter.

FBinNY 

You need to isolate the ptoblem to the shifter, cable/housing, or the RD itself. Start easy by shifting to low, and marking the inner wire where it emerges from the downtube fulcrum (cable stop). Then shift to high one gear at a time, helping by applying some hand tension. Observe the markings and see if it moves incrementally with each shift. (possibly you need to help it along with tension). If you can duplicate each step the shifter is probably OK, so it's only a matter of finding the cause of excess friction.

The most likely cause based on the history, is that the housing in pinching in at a ferrule or stop and trying to extrude through. That causes it to pinch down on the wire keeping it from moving easily. Fieldstrip everything and look at all the housing ends for one that looks like it's necked down.

Of couse if you don't see the incremental movement of your stop, then there is something wrong the shifter. Of you're lucky it's as simple a gummed up mechanism, or badly seated cable head.

pat5319

Does your rear derailleur cage align with your cassette cogs properly, (ie: parallel)? Check by standing behind the bike and eyeball it. It's extremely easy to bend the dropout, derailleur cage or derailleur, even by bumping a door. Been there done that and bought an alignment tool fix, also have straightened hundreds of rear derailleurs and hangers, in my mechanic days, for customers with similar issues.

Stratman351

Thanks for all the replies. Turned out the cable had shredded inside the brifter. Apparently it had stretched and then the strands began breaking, causing the inconsistent shifting, before just breaking completely.

achoo

Ultegra 6700 shifters? I've had that happen twice to mine. I think the bend the cable has to make down to the rotor might be a bit too small a radius on the 6700 shifters. I know the radius seems a bit larger on the 5700 shifters I have.