Rear derailleur cable either too tight or too loose
I have had my Giant Defy 3 for 10 months now. I am generally fairly mechanically competent but I don't know a lot about the subtleties of adjusting the gears because I haven't needed to learn so far. Now I do, so I'd appreciate a pointer about my rear derailleur.
I am fairly sure the two limit screws are more or less right as the mech lines up nicely with the smallest and largest sprockets at the two limits of travel. What I (think I) am struggling with is the cable tension.
When re-attaching it I have pulled it gently to take the slack out of the cable and then tightened the Allen key. I had a few goes at this but it is now tight enough so that moving the gear lever immediately moves the mech but not so tight that the mech has moved inwards from its detached position.
The problem I now have is that I seem to have a choice between having the highest or the lowest gear engage cleanly. If I loosen the cable a bit, the highest gear (smallest sprocket) engages cleanly but the derailleur struggles to get into the lowest gear - sometimes it works and sometimes it doesn't. If I tighten the cable a bit, the lowest gear engages cleanly but it won't shift into the highest gear at all. All the gears in between engage cleanly with a single click of the lever up and down.
Can anyone suggest how I might resolve this?
I am fairly sure the two limit screws are more or less right as the mech lines up nicely with the smallest and largest sprockets at the two limits of travel. What I (think I) am struggling with is the cable tension.
When re-attaching it I have pulled it gently to take the slack out of the cable and then tightened the Allen key. I had a few goes at this but it is now tight enough so that moving the gear lever immediately moves the mech but not so tight that the mech has moved inwards from its detached position.
The problem I now have is that I seem to have a choice between having the highest or the lowest gear engage cleanly. If I loosen the cable a bit, the highest gear (smallest sprocket) engages cleanly but the derailleur struggles to get into the lowest gear - sometimes it works and sometimes it doesn't. If I tighten the cable a bit, the lowest gear engages cleanly but it won't shift into the highest gear at all. All the gears in between engage cleanly with a single click of the lever up and down.
Can anyone suggest how I might resolve this?
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Comments
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Is the hanger straight? Also make sure the cable is clamped the correct side of the bolt. If these dont work, loosen the limit screws 1/4 turn each. See if this changes things at all. If it doesn't, put them back in to where they were.0
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Instead of tinkering with the cable itself, is there a threaded 'barrel' that holds the cable housing? Use the barrel to make 'fine adjustments' rather than the cable attachment.
Also make certain that the housing doesn't have overly sharp bends that restrict movement of the cable, and try a drop of oil on the cable at the ends of the housing.
Jay Kosta
Endwell NY USA0 -
Easy way to index gears, this is best done on a work stand. Or you can get someone to lift the rear wheel when you need to spin it.
1. Release the right hand shifter all the way so it's in position for the smallest cog.
2. Detach the cable from the rear mech.
3. Screw any barrel adjusters on the cable all the way in, there'll be one on the rear mech and possibly one near the shifters/on the down tube.
4. Pull the cable tight and re-attach at the rear mech.
5. Move your right hand shifter one step in.
6. Spin the cranks, (it's unlikely your gears will move straight away, but lucky you if they do).
7. While spinning the cranks, unscrew the barrel adjuster on the rear mech, eventually the chain will pop up to the next gear.
8. Try shifting up and down through all the gears, it should be fine.
If it's not quite right shift back down to the smallest cog and run from step 5 again, you should only need to make minor adjustments to get it spot on from there.
This video will make the above clearer and explain the limit screws too. Best video I've seen to demystify gears.
http://www.youtube.com/watch?v=SkzvfCaIbyQ0 -
I have gear issues too, I have it so it shifts into both biggest and smallest at the back but mid way through the cassette it doesn't shift cleanly through the gears, any idea what this could be, groupset if about 3 years old and guy at LBS said it might be because shifters are getting worn out but i'm not convinced by this?0
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Shifters or cassette and chain wear, I would start with if everything is straight.0
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+1 on a hanger bent out of alignment.
A lot of shifting problems that are resisting correction with normal indexing are down to the hanger being slightly bent (you won't see it with the naked eye). You need a Park Tool alignment tool to sort it, which your LBS should have.0 -
Thank you all for your help and suggestions.
I think it is working properly now although the fact that half a turn on the barrel adjuster is still enough to make my bike swap between the two problems I outlined makes me wonder how long it will work for.
I turned the H limit screw a small amount to move the derailleur slightly inwards as it looked ever so slightly too far out (but by a tiny amount) and I oiled the cable end. I did check the hanger alignment but, to the naked eye, it looks dead straight. I might still take Radial's advice and have the hanger checked properly.
Having done that I adjusted the cable tension using the barrel adjuster and it is now working. However, I strongly suspect that a small bit of cable stretch will see the problem recur. We shall see.
Again, thank you all for taking the time to help.0
