Inconsistent rear mech shifting

[Rusty Nails]

I normally have little trouble in getting the adjustment correct on rear mech shifting, but for some reason struggle with one of my bikes. It is on a carbon Genesis Datum with internal cabling (11 speed 105). Front mech shifting is just about OK.

Mainly issues with increasing the gears (down to smaller cogs). I know all the usual stuff about tension adjustment etc., but cannot get it right...my other four bikes are fine.

I am wondering whether the internal cabling through a cable liner in the down tube and the chainstay can cause more friction and stickier action than the traditional part open cabling, which might tie in with the problems moving up the gears.


Any ideas?

 

[All uphill]

I normally have little trouble in getting the adjustment correct on rear mech shifting, but for some reason struggle with one of my bikes. It is on a carbon Genesis Datum with internal cabling (11 speed 105). Front mech shifting is just about OK.

Mainly issues with increasing the gears (down to smaller cogs). I know all the usual stuff about tension adjustment etc., but cannot get it right...my other four bikes are fine.

I am wondering whether the internal cabling through a cable liner in the down tube and the chainstay can cause more friction and stickier action than the traditional part open cabling, which might tie in with the problems moving up the gears.


Any ideas?

Hanger alignment?

 

[dimrub]

Was the cable greased before routing it through the housing? When shifting up, you release the tension on the mech spring, but it won't "feel" it if the cable is not moving freely (certainly not if it's rusty or frayed).

 

[fritz katzenjammer]

Is it the correct chain and is it the correct way round?

B adjustment a bit big?

Bent lower cage?

 

[fossyant]

How old is the cable ? You may benefit for splashing out on better quality cables for internal routing. My FS MTB uses full housing (external routing) and it became less accurate at changing. A complete new quality cable fixed this (this was after a few years use).

Also check hanger !

 

[Paulus]

I would say change the inner and outer cable. Unless there is obvious damage to the hanger.
Does the mech move freely when the cable is detached. Does the cable move freely when detached?
Was it working alright the last time you used it, or have you changed something?
Start with the easy things first.

 

[albion]

Normally with that, I find I need a new inner cable.

 

[Rusty Nails]

Hanger alignment?

No problem there. Checked with my alignment tool.

Was the cable greased before routing it through the housing? When shifting up, you release the tension on the mech spring, but it won't "feel" it if the cable is not moving freely (certainly not if it's rusty or frayed).

Not greased. I have always avoided greasing inner cables due to the possibility of grit etc. sticking to the cable. May be worth a try.

Is it the correct chain and is it the correct way round?

B adjustment a bit big?

Bent lower cage?

Chain OK and no stretch. Will check the B adjustment, but visually looks OK. Lower cage looks straight

How old is the cable ? You may benefit for splashing out on better quality cables for internal routing. My FS MTB uses full housing (external routing) and it became less accurate at changing. A complete new quality cable fixed this (this was after a few years use).

Also check hanger !

Dura Ace cable about 1K miles old. I have changed the cable previously to see if that improved it.

I would say change the inner and outer cable. Unless there is obvious damage to the hanger.
Does the mech move freely when the cable is detached. Does the cable move freely when detached?
Was it working alright the last time you used it, or have you changed something?
Start with the easy things first.

When in the stand seems to move freely and have cleaned and oiled the mech. Nothing changed on set up of bike.


I think I will have to get new inner and outer cables...including the narrow plastic lining cable inside the frame. My bike needs new bar tape so that extra expense was necessary anyway.

 

[dimrub]

Not greased. I have always avoided greasing inner cables due to the possibility of grit etc. sticking to the cable. May be worth a try.

I think it's the common recommendation, especially when concerning the bikes, whose owners do not skimp on grams and cents, and cover their cables all the way from the shifters to the derailleur: it's an almost closed system.

 

[Ajax Bay]

Common it may be, but greasing (stainless, reputably sourced) inner cables is not recommended: it's so last century.
Feel free to offer a link suggesting that it's good practice, @dimrub
As for suggesting/implying that riders who don't grease their inner cables are cheapskates; have a word with yourself (or write more clearly).
For the OP: the outer loop round to the RD is the bit most likely to deteriorate and easy to replace. You will also be able to examine the condition of the inner section there.

 

[dimrub]

Common it may be, but greasing (stainless, reputably sourced) inner cables is not recommended: it's so last century.
Feel free to offer a link suggesting that it's good practice, @dimrub

I'm not sure where I saw it first - it may have been on the bikespeeds YT channel (that guy is a world champion in greasing and oiling). But it came in timely, since I was dealing at that time with so many bikes in which the cables not just didn't move freely - they were rusted in into the outer, so it seems like a good idea, especially for bikes that are in danger of rust.

As for suggesting/implying that riders who don't grease their inner cables are cheapskates; have a word with yourself (or write more clearly).

Sorry, this was not my intention. What I had in mind is the strange design choice of manufacturers, of running the cables outside of an outer every time there is a straight stretch of tube to run it along. I can only conjecture that this has to do with saving on the outer, as well as its weight, but maybe there are better reasons for that.

 

[Punkawallah]

I'm not sure where I saw it first - it may have been on the bikespeeds YT channel (that guy is a world champion in greasing and oiling). But it came in timely, since I was dealing at that time with so many bikes in which the cables not just didn't move freely - they were rusted in into the outer, so it seems like a good idea, especially for bikes that are in danger of rust.



Sorry, this was not my intention. What I had in mind is the strange design choice of manufacturers, of running the cables outside of an outer every time there is a straight stretch of tube to run it along. I can only conjecture that this has to do with saving on the outer, as well as its weight, but maybe there are better reasons for that.

There has to be a cable stop somewhere, I suppose.

 

[Rusty Nails]

Have bought new, good quality inners and outers and hope to fit them in the next week. Will update this thread with the outcome.

 

[Rusty Nails]

Update. Have fitted new inners and outer casing and left off the narrow lining casing that ran through the frame. Shifting is now fine both up and down the cassette.