Annoying indexing problem.

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I've been setting up my indexing on a stand and all seems fine, however when i'm on the road i seem to have problems changing up gears on the rear. I've got a 105 groupset. If i flick the brake to pop it down gears I have no problems at all. However, if i'm on either of the two largest cogs on the rear then releasing the tension to change up doesnt seem to work well (for either position on the front). The chain will rattle away until i flick it up another gear and then it will jump up and continue to rattle, trying to get into the next gear. Another up-change will pop it in the right gear without issue.

It seems a bit like a sticky cable to me, but its strange that it only happens under load, and only for the lower two of the gears.

Any thoughts? The bike has done 1500 miles approx and is 3 years old. I've only had it for 6 months and put 1200 on it, but i doubt the cables were ever replaced previously. Do you think this is a good place to start? I've lubed the mech's up with GT85 to no avail.
 

Big Nick

Senior Member
Have you tried setting it up from scratch undoing the pinch bolt etc?

Most indexing issues can be sorted with tuning the cable tension, if that fails to solve it its time to start looking at your cables and components
 

Han69

Regular
I've been setting up my indexing on a stand and all seems fine, however when i'm on the road i seem to have problems changing up gears on the rear. I've got a 105 groupset. If i flick the brake to pop it down gears I have no problems at all. However, if i'm on either of the two largest cogs on the rear then releasing the tension to change up doesnt seem to work well (for either position on the front). The chain will rattle away until i flick it up another gear and then it will jump up and continue to rattle, trying to get into the next gear. Another up-change will pop it in the right gear without issue.

It seems a bit like a sticky cable to me, but its strange that it only happens under load, and only for the lower two of the gears.

Any thoughts? The bike has done 1500 miles approx and is 3 years old. I've only had it for 6 months and put 1200 on it, but i doubt the cables were ever replaced previously. Do you think this is a good place to start? I've lubed the mech's up with GT85 to no avail.
I would change the cable set, and start from scratch.
 

Smokin Joe

Legendary Member
I'd go for cables to start with. Even if that turns out not to be the cause of the current problem (And it sounds like it is) new cables will transform the gear shift. An oft neglected but worthwhile replacement.
 
OP
OP
Mark1978

Mark1978

Veteran
Have you tried setting it up from scratch undoing the pinch bolt etc?

Most indexing issues can be sorted with tuning the cable tension, if that fails to solve it its time to start looking at your cables and components

Yep, have set it up from scratch a couple of times. Works perfectly on the stand but then once im out on the road i see the same issue.

I'll look into changing the cables tomorrow. Will have to do a bit of research on what i need. Never done cables before. They are internally routed.
 

Smokin Joe

Legendary Member
That's the stuff. Remember you'll need some bar tape too.

Cables are quite straightforward if you take your time. After you've removed the old tape take a couple of pictures of the bike showing clearly how the cables run and where they are held to the shape of the bars with insulating tape. Use the old outers as a guide when cutting the new ones, nothing is more frustrating than finding you've cut one too short and have to get another. When you are curving the cables round the bend of the bars use cable ties to pull them snug into the inner radius. You can cut these off after you've then secured them with strips of insulating tape.

Gear inners on Shimano are a bit of a pig to thread into the shifter (Compared to Campag anyway), make sure you note exactly where the old ones pull through as you remove them. And have the chain on small/small combination before you fit the cables, that is the default starting position for the indexing.

Also make sure you fit the supplied ferules to each end of all the gear outers otherwise the outer will compress as you shift and you won't index properly. The brake outer does not have a ferule at the end which goes into the shifter, just one where it joins the caliper, although these are not essential. My front outer does not have one because I dropped it and could not find it again.
 
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Han69

Regular
That's the stuff. Remember you'll need some bar tape too.

Cables are quite straightforward if you take your time. After you've removed the old tape take a couple of pictures of the bike showing clearly how the cables run and where they are held to the shape of the bars with insulating tape. Use the old outers as a guide when cutting the new ones, nothing is more frustrating than finding you've cut one too short and have to get another. When you are curving the cables round the bend of the bars use cable ties to pull them snug into the inner radius. You can cut these off after you've then secured them with strips of insulating tape.

Gear inners on Shimano are a bit of a pig to thread into the shifter (Compared to Campag anyway), make sure you note exactly where the old ones pull through as you remove them. And have the chain on small/small combination before you fit the cables, that is the default starting position for the indexing.

Also make sure you fit the supplied ferules to each end of all the gear outers otherwise the outer will compress as you shift and you won't index properly. The brake outer does not have a ferule at the end which goes into the shifter, just one where it joins the caliper, although these are not essential. My front outer does not have one because I dropped it and could not find it again.
Pretty easy on the Claris to Tiagra, and not difficult on 105's
 

arch684

Veteran
when replacing internal cables a good tip is to remove the old outer but leave the old inner cable in then you can slide the new outer on to the old cable then pull the old inner out and slide the new cable in.
 

Shut Up Legs

Down Under Member
when replacing internal cables a good tip is to remove the old outer but leave the old inner cable in then you can slide the new outer on to the old cable then pull the old inner out and slide the new cable in.
Nice :smile:. I'll try to remember that the first time I change the cables on my Specialized Roubaix, which has internally-routed cables also.
 

jack smith

Veteran
Location
Durham
Or if you cant do that tie abit of string to the end of the inner cable before you pull it out through the frame then tie it onto the new cable and pull trough internal cables dont need an outer
 

Shut Up Legs

Down Under Member
[QUOTE 3254366, member: 45"]My Tricross has a plate where the cable comes out of the frame. Unscrew this and there's plenty of room to fish the new cable out of the tube. Your Roubaix may be the same.[/QUOTE]
While cleaning the Roubaix just now, I noticed it has a plate (with a very small hex bolt holding it in place) just where the rear brake cable exits the top tube, just in front of the seat tube. I haven't found any other such plates, though.
 
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