So it begins with my starting to have trouble shifting the rear mech on a well run-in and well maintained cassette and chain combo. Due to the routine I have and the age of the cassette and chain I began to suspect worn components.
I’m quite disciplined about changing my chains at 0.5% and have rarely had cause to measure a chain at the 0.75% point.
This Shimano chain was not unduly elongated.
(i.e. by more than about 1/16th over 12”: I use 1/8th indications on a steel inch rule over 12 links)
Consequently, I considered that perhaps the cassette was now worn (it had seen this and one prior chain - though I can't tell you how many Kms exactly) so before the event this weekend I purchased a new chain and cassette pair.
I had already replaced the gear cable, and the rear mech is quite new (having replaced it when the original one stripped a thread when cleaning the jockey wheels).
Here are the basic details:
The machine is a 2010 trek Madone 4.7 (Ultegra with Fulcrum Racing 5CX Wheels and Conti 4Ks) it has a relatively new Ultegra rear mech, new gear shifter cable, new Ultegra 11-28 10 speed cassette and Connex Wipperman 10 speed chain (a favourite from years commuting).
The problem is indexing and the symptoms are described in the process detailed below (see red text for quick reference).
Basically, when I gave up trying to dial it in and rode a century this weekend I found I had a lot of noisy gears, several hesitating and some that would skip a sprocket, leading me to be shifting up and down and cross chaining because the small front chainring was not playing nice across its ideal range. Actually I had more than half my gears quite functional, quiet and at all the necessary points across the range but it was frustrating and because I have always expected more of my work I was disappointed I couldn't work out what was going on.
The only component I’ve not been able to assess properly is the dropout hanger, although I have no reason to suspect it and it looks ok and seemed to be fine for the last few Services.
In troubleshooting the problem I have replaced everything mentioned above (except the dropout) and thoroughly cleaned and regressed the shifter. I can confirm the cable I installed is correctly seated up front and I stretched it during install.
The wheel is a fulcrum 5 with a 11speed freehub that I use the supplied spacer for 11 to 10 speed conversion. I have also attempted to solve the issues by setting up with and without the 0.8 shimano supplied shim.
My process is some variation of the following:
- 1) detach or release cable tension and set H and L limits by hand;
2) screw tension adjuster all the way in and then back out 1-1.5 turns;
3) confirm the shifter is fully released to highest gear stop;
4) leaving the chain on the big ring re-tension the cable so chain returns to highest gear when shifted down and then back up;
5) fine tune tension so there is minimal slack and hesitation in the lever to downshift and chain is just backed off from contacting the next sprocket (not noisy);
6) proceed to downshift and upshift progressively to get indexing all the up to the 28.
7) Now many guides suggest adjusting the tension with turns of 1/4 or there abouts in each gear to fine tune the indexing but I find that doing this alters the tension at the H limit point so that the chain no longer drops into it. This leads me to wind the tension out (back) to the original position;
8 ) having confirmed and adjusted the L stop and tension to cleanly climb into the 28, I find that when shifting down I can rarely get it to drop onto the next gear but it tends to drop and settle on the 3rd highest, though I can is the lever to position it on the 2nd where it should have gone (and a subsequent downshift works as expected usually
9) the end result seems to be hesitation (shifting up) or double sprocket changing throughout the upper gears (shifting down) throughout the middle cluster.
10) I began working on the problem using both front chain rings but this did not make any material differerence that I could discern;
11) although I serviced the shifter and it feels positive and precise it could be that it is worn or malfunctioning I guess;
12) I will order or make a hanger alignment tool this week as it is something worth having but as a result I can’t rule out the hanger either.
13) since the problem is not improved with a new chain and cass (and cable) and the rear mech is fairly new too (about 1200km) I am at a loss as to what I’m doing wrong
14) I have had my share of frustrating sessions indexing in the past while I learned the process has become one I tackle with confidence and patience which I enjoy until this current issue
What do you guys think? I'm keen to hear thoughts on how to narrow down the possibilities further than I have.