Gear Cable Inner Replacement - Giant Defy Advanced Disc

[timnoyce]

Guys,

I know that this is quite a popular road bike amongst forumites here, and having had mine since November it's time for a new set of inners.

Question is, how easy is the gear cable inner process? I've not looked too closely yet, but I have the Dartmoor Classic on Sunday and feel that the bike will perform better if I do this prior to the ride but don't want to mess about as my free time this week is somewhat limited.

If I am careful should it just be a case of removing the inners from the outer/liner, and then poking the replacement cable back in again through the frame? I am an internal cabling novice and so don't want to shoot myself in the foot and regret starting the job!

Thanks in advance,

[snotrag]

What makes you think that the 7 month old inners need replacing?

[timnoyce]

There's friction amd they feel a bit tired. They've done 5,000k over winter. New inners is the answer I'm sure.

[okgo]

Yes it should be fairly straight forward, but if your guess is wrong and its actually the outer which is causing friction, then you could splay the new cable by pushing it through or potentially push the outer inside the frame making it a very annoying job.

[upsidedownmark]

It's almost guaranteed to be a pig of a job. There's no inner inside the frame, the inner runs free. Getting it from the entry point to the exit point is quite a game. There are tricks but if you've never done it before I certainly wouldn't start messing with something important on sunday.

Likewise, if the gears change when you press the button, I'd leave well alone. FWIW I think it was about 4 years before I changed my inners, and I don't reckon they really needed doing..

[okgo]

upsidedownmark said:

It's almost guaranteed to be a pig of a job. There's no inner inside the frame, the inner runs free. Getting it from the entry point to the exit point is quite a game. There are tricks but if you've never done it before I certainly wouldn't start messing with something important on sunday.

Likewise, if the gears change when you press the button, I'd leave well alone. FWIW I think it was about 4 years before I changed my inners, and I don't reckon they really needed doing..

Do you know that is true re no internal cable guides on that bike? Quite rare if so, almost all frames I've had with internal cabling have guides - the Tarmac has a thinner black outer than goes inside the frame.

The best way for anything to do with trying to thread a cable, with or without outer is to use a very strong magnet, you can then easily guide the cable by holding the magnet against the frame and moving it down as the cable goes, then when it gets near the hole the magnet will bring it to the entrance. Its quite easy then, without its horrible.

[timnoyce]

OK I take heed of your advice. I'll just give it a ruddy good clean as the front shifter cable is sticking so that once you've shifted from big to small rings it takes a while to pull through so that you can shift back again. I'd like to say is just man up and ride the 50 all day bit not sure Dartmoor will let me.

[astroarcadia]

Internal cable routing on my Canyon is sleeved with a very thin clear plastic straw. Without this it near impossible to thread a new cable around the BB and back up behind the front mech.

Jobs like this are fiddly and frustrating unless you have all the kit - I'm happy to have a tinker leave replacement cable inner and outers to my LBS for what it costs.

[upsidedownmark]

okgo said:

Do you know that is true re no internal cable guides on that bike? Quite rare if so, almost all frames I've had with internal cabling have guides - the Tarmac has a thinner black outer than goes inside the frame.

The best way for anything to do with trying to thread a cable, with or without outer is to use a very strong magnet, you can then easily guide the cable by holding the magnet against the frame and moving it down as the cable goes, then when it gets near the hole the magnet will bring it to the entrance. Its quite easy then, without its horrible.

Interesting. No, I don't know the giant, but I've only ever come across one bike (a blue triad) that was internally sleeved - so from my point of view it's quite rare that they are (and I'm the guy that half the club gets to fix their bikes, so I've seen a few..) That includes two specialized frames (alias and a something forgettable - not a tarmac)
Most are delivered with the white plastic straw as an aid to threading the first time, but unless you either keep that, or have long enough lengths of spare outer to push in over the old cable / thread the new through before pulling it out, it's back to fishing.

Didn't say it was impossible, just that it's not a good idea < 1 week before an important event when you don't know what you're doing..

[Chirpsean]

The inner routing of my Defy 2 has a sleeve all the way through on the front changer but on the rear the sleeve goes down the down tube, round the bottom bracket but finishes in the chain stay. To do mine I just wrapped some cotton around the inner at the rear mech and pulled it through.

[Ballistic]

okgo said:

upsidedownmark said:

It's almost guaranteed to be a pig of a job. There's no inner inside the frame, the inner runs free. Getting it from the entry point to the exit point is quite a game. There are tricks but if you've never done it before I certainly wouldn't start messing with something important on sunday.

Likewise, if the gears change when you press the button, I'd leave well alone. FWIW I think it was about 4 years before I changed my inners, and I don't reckon they really needed doing..

Do you know that is true re no internal cable guides on that bike? Quite rare if so, almost all frames I've had with internal cabling have guides - the Tarmac has a thinner black outer than goes inside the frame.

The best way for anything to do with trying to thread a cable, with or without outer is to use a very strong magnet, you can then easily guide the cable by holding the magnet against the frame and moving it down as the cable goes, then when it gets near the hole the magnet will bring it to the entrance. Its quite easy then, without its horrible.

I recently replaced the rear inner brake cable on my Defy Advanced SL1 (2 years old) and can confirm that there is no cable guide running all of the way through the frame toptube. I ended up using one of the small magnets from the Park Tool kit and even then it wasn't a simple 5 minute job.

Edited by Ballistic on Wednesday 22 June 21:33

Edited by Ballistic on Wednesday 22 June 21:34

[okgo]

If you have a few strong ones attached to something like a nail head which will fit into the frame it's very easy but I've had a lot of practice! Sodding bikes!

[timnoyce]

Ok, I've decided to not attempt it this week for fear of not being able to put it back together again in time.

I've actually narrowed the issue down to that of perhaps not the cable inner. I think that there might be an issue with the left hand shifter as I can drop from the big ring onto the small ring, but then when I shift back up to the big ring the lever is slack and there is no pressure to engage the shift. If I bash the handlebars a bit or ride over some poor quality tarmac then it eventually starts to work again.

I had it apart yesterday to take a look as best I could under the hood and can't see anything too untoward but can see that the cable tension isn't releasing properly. I sprayed a healthy amount of MO94 in there (muckoffs answer to GT85) and will give it another poke tonight.

They're Tiagra 4700 shifters and up to now have been excellent! I googled it and it seems I'm not the only person to suffer this problem although it doesn't seem widely reported.

If anyone has any ideas then I am all ears!

[okgo]

Could be something shifter related if its got crap in it, or still could be the cable or outer that isn't moving smoothly allowing the lever to take up the slack...

[Usget]

It's not something silly like the cable getting gunked up where it wraps around the bottom bracket is it?

[upsidedownmark]

I'd suspect a lever issue. If it drops down to the small ring, the cable is moving OK - it has to for the mech to move. If it's not hooking the cable to go up, then I'd suspect a pawl in the lever mechanism is failing to engage.

Do you have to use quite a lot of force to drop it from the big to small? There was a failure mode where the limit screw is too tight and it stops the mech before the gear clicks in - you hook the shift into the big ring with a lot of force by against the give in the system, holding the pawl under a lot of tension. In reverse, you have to use quite a lot of force to release the gear (because it's under massive tension), which ultimately leads to the (cast) pawl piece breaking inside the lever..

[timnoyce]

When it is working, then the feel of the shift lever actually feels quite normal and it shifts as crisply as always. It started as an intermittent issue happening quite rarely, but now it happens with every shift. A couple of hefty tts on the hood with the palm of my hand and it will engage again.

I couldn't see anything obvious under the hood, and it all looked very clean. When I get home I will unbolt the cable from the mech and see if I can get it to shift controlling the cable tension by hand. It can go back to the bike shop for them to diagnose the issue but I didn't have much hope that they'd turn it around in a day and have it back to me by the weekend when I go away for the week. The bike was new in November so would hope that it's covered by warranty as I don't feel that I have particularly 'abused' it.