Indexing/Shifting Issue! Aaargh

rider25

Hi folks,

I've a Giant TCR with Ultegra groupo (a 105 cassette being the exception) and for the past few months have had issues with being able to properly index the gears. It's been one niggle after the next.

So after changing the rear gear cable, having the hanger aligned, making sure the right spacer combo was on the cassette (11 speed wheels so a 1mm and 1.85mm are on) and finally yesterday replacing the rear gear cable outer/housing I'm still having problems.

Specifically, the problem that remains is shifting from the 10th sprocket to the 9th - it takes to clicks to change. All other shifts are responsive. If I make an adjustment in order to shift smoothly from 10 to 9, it throws the other gears out.

Cable is sitting on/under the frame properly btw.

Any ideas?

meanredspider

The only thing that springs to mind is whether you have the tension right in the cable and the limit screw set correctly. I'm guessing it's the limit screw - that's where I'd start. Adjust it so that it only just makes 10th and then ensure that the cable tension is right so that it makes the shift to 9th on the first click.

rider25

Thanks, meanredspider.

I have adjusted the limit screw but probably not since the cable housing was switched. Will give it another go!

keef66

Is the cable attached on the right side of the pinch bolt on the rear mech? Have a look on Shimano Tech Docs for the full service instructions.

drlodge

To make sure the RD is perfectly aligned, I prefer to take the chain off. Then rotate the RD so the upper jockey wheel comes into contact with a sprocket - then you can see if its exactly in line. Try this on different gears just to make sure there's nothing funny going on.

rider25

Thanks folks - great tips. Will report back if I ever conquer it. ;o)

k-dog

Did you change the housing? - especially the loop at the rear derailleur. I've had clunky shifting for a few weeks, new outer and it's perfect again.

That part is especially susceptible to getting clogged up due to its position.

rider25

Sorry for the delay in closing this one off and thank you, k-dog, for your response - I've only just spotted that.

I ended up taking it to a 3rd LBS that, rather fortunately for me, where one of only 5 bike shops across the globe to be takig part in a Shimano placement scheme. This meant hat they had a couple of Shimano mechanics/technicians working in their store. You couldn't make it up!

Anyway, the main problem was the KMC chain despite it being compatible. They also re-routed the gear cables to the rider's side of the bars rather than the front of the bars. Shimano techs said this is how they should be routed - news to me and it's never been the factory set up on my bikes.

Rides like a dream for the first time in months. The LBS is Ride On in Rawtenstall and the service received was first class too.

dj58

rider25 wrote:

Anyway, the main problem was the KMC chain despite it being compatible. They also re-routed the gear cables to the rider's side of the bars rather than the front of the bars. Shimano techs said this is how they should be routed - news to me and it's never been the factory set up on my bikes.

So what was the problem with the KMC chain, and what explanation did the Shimano Tech's give for routing the control cables on the rear of the bars?

rafletcher

The chain thing (unless it was the wrong "speed" one) is, I suspect, just Shimano being Shimano and recommending their own. My new Genesis is 105 11sp and came with a KMC chain a standard, and shifts flawlessly. As to cable routes, I've always used the "back" of the bars myself (ie rider side)

dj58

rafletcher wrote:

The chain thing (unless it was the wrong "speed" one) is, I suspect, just Shimano being Shimano and recommending their own. My new Genesis is 105 11sp and came with a KMC chain a standard, and shifts flawlessly. As to cable routes, I've always used the "back" of the bars myself (ie rider side)

I'm interested to know the reasoning behind what the Shimano Techs said/did regarding the cable routing as it implies that shifting is better that way, Or was their personal preference. Agree about the chain, but was there a fault with the KMC chain or did they just swop it out to eliminate it as a source of a problem and if it was not a problem and not excessively worn why not refit it.

Hopefully the OP will come back and tell us.

Manc33

Is your rear wheel/tyre/rim exactly central in the frame?

I had this problem and it was because my cheap wheelset wasn't dished properly. The dish was out so the cassette was further away from the rear mech than it should have been. The dish was at least 10mm out. After tightening all the non-drive side spokes (that were loose) it fixed it.

Don't even touch it if you don't know how to tension wheels. :P

marcusjb

Manc33 wrote:

Is your rear wheel/tyre/rim exactly central in the frame?

I had this problem and it was because my cheap wheelset wasn't dished properly. The dish was out so the cassette was further away from the rear mech than it should have been. The dish was at least 10mm out. After tightening all the non-drive side spokes (that were loose) it fixed it.

Dishing doesn't affect the cassette's position. That is a fixed position on the axle. A cassette can not be moved side to side by changing spoke tensions.

Dishing is centring the rim between the axle ends.

(but do make sure your wheel is properly seated in the drop outs anyway)

Manc33

OMG :oops:

This is why my sig exists.

IMO gear changes are always pretty sloppy there no matter what you do, but its usually because you changed from say a 32T max sprocket to 28T and didn't unwind the b-tension out a little to compensate. If the rear mech isn't close in the lowest gear, changes on the two smallest sprockets will be sloppy (or not even change at all).

itboffin

If you're still having problems and you're running a 105 chain take a look at the direction its mounted, I almost went mad fitting a 5700 group set until by chance I noticed the instructions indicating direction after I swapped it shifting was / is perfect.

rider25

Hey,

The chain was definitely highlighted as being the primary cause of the problems (the KMC one was the right size chain, non-directional btw). Not sure what was wrong with it - it hadn't done more than 1000 dry miles or so, was well maintained and had very little wear. No obvious damage either. I still have the chain if anyone has any theories.

I accept that they are bound to recommend a Shimano chain and I reckon any replacement 10-speed chain may have fixed the problem.

Neither am I sure of the reason for routing the cables around the rear of the bars for that matter. The resident mechanics didn't 'sell' it as fixing the issue, more the case the Shimano techs suggesting that it's best practice. The cable outers are Dura Ace if that makes a difference to how it should be routed. Suspect not.

Sorry I don't have the answers to your questions - I guess I was just relieved that such a persistent issue had been resolved.

Manc33

Who remembers those "Sedisport" chains? My dad used to buy those instead of Shimano ones. When I got my (SRAM) chain, I just got the best one I could in that speed, the PC870. Only a tenner. Some say running a 9 speed chain on 8 speed can alleviate some chain rub, on triples. Since OP is on a 11s double, that's out.

I was going to get a KMC next lol. That gold X8PL one yummy.

dj58

rider25 wrote:

Sorry I don't have the answers to your questions - I guess I was just relieved that such a persistent issue had been resolved.

O.K. Thanks for replying anyway.

wongataa

rider25 wrote:

Neither am I sure of the reason for routing the cables around the rear of the bars for that matter.

I am guessing that it is due to the fact that if you route the cables this way the bends will have the largest radius it is possible to get. Tighter bends can cause problems due to increased friction.

keef66

wongataa wrote:

rider25 wrote:

Neither am I sure of the reason for routing the cables around the rear of the bars for that matter.

I am guessing that it is due to the fact that if you route the cables this way the bends will have the largest radius it is possible to get. Tighter bends can cause problems due to increased friction.

Been browsing Shimano tech docs. With the older generation of shifters they had 2 exit routes offering routing to the front or the rear of the bars. As mentioned above, to the rear offers lower friction.

I note the newer shifters only have one exit point and the manuals show illustrations of cables routed along the front of the bars...

rider25

Manc33 wrote:

Who remembers those "Sedisport" chains? My dad used to buy those instead of Shimano ones. When I got my (SRAM) chain, I just got the best one I could in that speed, the PC870. Only a tenner. Some say running a 9 speed chain on 8 speed can alleviate some chain rub, on triples. Since OP is on a 11s double, that's out.

I was going to get a KMC next lol. That gold X8PL one yummy.

It's a 10 speed actually. The mention of 11 speed was the wheel compatibility - the correct spacers are on though. ;o)