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  1. #1
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    Cable stretch symptoms?

    Hello all - I'm pretty new to the forums as well as to bike repair/upgrade, so I'm looking forward to learning a lot from all of you!

    I have a Gary Fisher Sugar 3+ MTB as well as a Fuji Palisade hybrid (I think?). On both bikes, there are some issues with shifting.

    On the Fuji (21 spd - all Shimano GS200 - it's OLD):
    • The shifter for the FD doesn't click like the shifter for the RD - should it?
    • The RD skips the 2nd largest cog when shifting up the cassette (to larger cogs) and the 2nd smallest cog when shifting down the cassette (to smaller cogs)
    • I have to click twice to get off the largest cog and similarly to get off the lowest cog
    • Every once in a while, I have to click twice to shift in the mdidle gear ranges as well
    • It also seems that the RD indexing is off - I've not read up on how to adjust the indexing ... I assume there's some sort of cog inside the shifter mechanism ...


    On the MTB (27 spd - Shimano XTR FD/RD and Deore Mega shifters):
    • To get any shifting at all of the RD, if I click once, nothing happens, but if I click twice, it shifts, but sometimes skips cogs. When it's up on the bike stand, it seems to shift correctly, but when I'm actually riding it, shifting is not reliable at all. It all seems to be the case regardless of which chainring I'm on.
    • Also, once I shift, if I try to shift again, the lever just goes "to the floor" so to speak the first time I press it, then seems to reset and grab the second time.


    Are these symptoms of cable stretch? Or something else?

    Thanks for your advice!
    bsker

  2. #2
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    To be honest, with the Fuji, if it's that old, the chances are the shifting would perform a lot better with new cables. The left-hand shifter may not click because it's a friction shifter - there are no "click" positions, allowing you to finely trim the position of the front derailleur cage to avoid chain rub. Indexing on shifters generally cannot be "adjusted", you have to set the cable tension correctly to place the derailleur over each gear with each click. If you're not familiar with how to adjust stuff or replace cables, I suggest looking up the Park Tools tutorials and visiting Sheldon Brown-Bicycle Technical Information, as both are very useful resources.

    As for the MTB, that could very well be a cable tension issue, but again, if the cables are more than a year or two old, you might be better served by replacing them, especially if the bike gets a lot of offroad use where dirt might get into the cable housings.
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  3. #3
    Senior Member Retro Grouch's Avatar
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    Hmmm.

    1. What do your shifters look like? If it's just a single lever for your thumb, your front shifter is probably a friction component and isn't designed to click. Personally I prefer it that way because, for one thing, it lets you trim your front derailleur.

    2. Disconnect your rear shift cable, start all the way at one end with your shifter and count the number of clicks. A 7-speed shifter should have 6 clicks. One possibility is yours has 7 (meaning it's an 8-speed shifter) because that's exactly how they act.

    Another likely possibility is you have a bend derailleur hanger. Shift into a gear that makes your derailleur arm point straight down. Now prop your bike up vertically and look at it from the back. If your derailleur arm seems to be pointing in toward the back wheel - that's it. You need to replace the derailleur hanger if it's replaceable or else bend it back straight.
    My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.

  4. #4
    Senior Member bikeman715's Avatar
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    sound like your hanger is bent see here how to fix it , Park Tool Co. ParkTool Blog Rear Derailleur Hanger Alignment and for the shifting problem see here http://www.parktool.com/blog/repair-...s- .derailleur
    bikeman715

  5. #5
    Senior Member Flyingblind9's Avatar
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    x cMany things could cause a bike to shift improperly. Now the indexing is done with your shifters, not on your rear derailleur. Say for instance the rear derailleur is adjusted properly, and your shifting is still poor, I wouldn't blame the shifters being indexed wrong, but I would first look at the cables tension. If the cable seems loose or really tight in positions that wouldn't seem right, then the tension is wrong. One way of checking for tension is to first make sure the cable moves smoothly in the housings. For your bike since it is aging, I'd recommend recabling it because poor cable movement makes shifting really unreliable when most people immediately think of the indexing being off when in reality if the cable doesn't move, the shifting suffers.

    If you want to adjust the shifting yourself there are a few steps you'd need to follow assuming your cables are new or in good condition and for shifters that are indexed.

    Rear Derailleur:
    -Disconnect the shift cable from the derailleur and move your front shifter to the large chainring. the chain should immediately and effortlessly move to the smallest rear gear. When pedaling it, check to see if the cogs on the rear derailleur are perfectly aligned with the small cog. Its easily checked just like looking down the edge of ruler. If its straight your good! If not, move the screw that adjusts the lower limit until it is corrected.
    -Now move the whole mechanism by hand after shifting to the small front chainring to the largest rear gear and also check for alignment. Correct if necessary.
    -Now that the limits of the derailleur is set, you have to index the gears. Reattach the shift cable in the large chainring and small rear gear and make sure the barrel adjuster on the rear derailleur is tightened down. That is how you will adjust cable tension. Move the shifter to the position that marks one gear shift up from the smallest rear ring. If it doesn't shift, unscrew that barrel adjuster on the derailleur until it shifts. Then move again to the smallest gear and see if it goes promptly.
    -Once that is done, then move the front chainring to the smallest gear and shift all the way up to the smallest rear gear and do the same process for the top two gears. When the top two gears shift easily and the bottom two gears also do the same, the rest will fall into place.

    Note: for shifters that are not indexed, setting the limits and making sure the cable is tight, that is all that is necessary because you can move the derailleur with the lever as much as necessary to shift gears.

    Hopefully this helps! Luckily there are MANY Youtube videos demonstrating this same procedure if it is easier to see someone do it =)

    One last note is that if your cables are replaced and it is adjusted to shift perfectly and after about 100-300 miles or so the shifting is awful again, then indeed that is caused by cable stretch because the cables are settling into place. Typically many gears like 10 and 11 speed systems need adjusting more readily than 7 or 8 speed due to the low tolerances between gears and the vibration and jostling that riding simply induces on the bikes. Improperly cleaning the chain, cogs and derailleurs can also affect shifting if a lot of buildup is present.
    Last edited by Flyingblind9; 08-19-14 at 12:12 AM. Reason: Content

  6. #6
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    Need a new rear der. cable/housing and spray some solvent into the shifter.



    Jon

  7. #7
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    Update on the shifting ...

    And for further reference, the shifter I am working with is a Shimano SL-M510 (see pic).

    ...after experiencing the shifting problems I described on Saturday, I went for a ride on Sunday. Shifting up (thumb lever) was almost completely gone - once in a while I could jiggle the shifter or press it 7-8 times and the derailleur would finally catch and shift up. Shifting down (index finger lever) was acting as normal - 1-2 clicks and it would shift down (i.e., to larger cogs - am I saying that correctly?).

    I went back out on Monday morning (I was out of town and didn't have time to work on it before then and accepted the possibility of riding a 3-speed instead of a 27-speed), and it actually shifted better, back to its old tricks ...

    I have not changed the cables since I've owned the bike, so that's probably the culprit ... after how many miles does one usually change cables? Obviously there are variables there other than just miles, but in general - any recommendations? Any given year, I've probably ridden less than 200 miles per year on it - now that I'm interested in riding more, I really want/need to learn how to fix/maintain things a little better ...

    Also, the little red indicator on the shifter does not move even though the shifter still clicks and still works through 8 clicks for a 9-speed - I don't really care, but I don't know if that's an indication of something not being connected properly inside the shifter.

    Quote Originally Posted by Flyingblind9 View Post
    ...unscrew that barrel adjuster on the derailleur until it shifts...
    Flyingblind, the derailleur doesn't have a barrel adjuster on it (see the pic - the metal nut doesn't really adjust anything as it's more of a bushing than anything else) - there is one near the shifter though - is the direction of rotation the same though? Clockwise to help shift to higher gears and counter-clockwise to shift to lower gears, i.e., is unscrewing at the shifter still loosening the cable? And when you install a new cable, should the barrel be threaded about half way to make room for later adjustments?

    Thanks for all the input!
    IMG_20140819_114512[1].jpgIMG_8263[1].jpg
    bsker

  8. #8
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    That first issue with the shifter not "catching" sounds like it might be gummed up with old lubricant. It's a known issue with Shimano shifters, I've seen plenty about it on here and experienced it on several occasions, flush the shifter out with WD-40 or GT-85 or something and see if that helps. It certainly won't hurt.

    As for the barrel adjuster, think about it for a minute. When you unscrew the adjuster from the shifter housing, you're effectively lengthening the cable housing slightly by doing it, which has the same effect as shortening the cable - it tightens the cable.
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  9. #9
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    Quote Originally Posted by Airburst View Post
    ...As for the barrel adjuster, think about it for a minute. When you unscrew the adjuster from the shifter housing, you're effectively lengthening the cable housing slightly by doing it, which has the same effect as shortening the cable - it tightens the cable.
    Airburst, in terms of the shifter barrel adjuster, I imagine that unscrewing them from the shifter housing more or less "pushes" the shifter away from the nearest cable housing stop in the frame, in effect tightening the cable - is that what you're saying?

    OTOH, if you look at my picture from a couple posts ago, the nut on the derailleur does not screw into the derailleur itself. Instead, it screws into the red portion of the pulley (what is all that stuff, and what is it's purpose? I don't think it's officially part of the derailleur, is it?) ... in that sense, unscrewing it from the red piece would ultimately push the derailleur away from the shifter, which still has the effect of tightening the cable, right?

    Finally, I believe these are rapid rise shifters, i.e., they move UP the cassette (towards the larger cogs) when there's no tension ... so if I have trouble shifting into the smaller cogs, I should tighten the cable (unscrew the barrels) and I should tighten the barrels (loosen the cable) if I have trouble shifting into the larger cogs, correct?

    Either way, I think I also have a separate issue that makes adjustment difficult - I believe that one of derailleur plates is bent. Is there a place to buy parts for derailleurs without having to buy the entire derailleur itself?

    Thanks,
    bsker

  10. #10
    Senior Member Flyingblind9's Avatar
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    Quote Originally Posted by bsker View Post

    Flyingblind, the derailleur doesn't have a barrel adjuster on it (see the pic - the metal nut doesn't really adjust anything as it's more of a bushing than anything else) - there is one near the shifter though - is the direction of rotation the same though? Clockwise to help shift to higher gears and counter-clockwise to shift to lower gears, i.e., is unscrewing at the shifter still loosening the cable? And when you install a new cable, should the barrel be threaded about half way to make room for later adjustments?

    Thanks for all the input!
    IMG_20140819_114512[1].jpgIMG_8263[1].jpg
    bsker
    The barrel adjuster near the shifter works the same way as on the rear derailleur. Typically when you need to replace cables I tend to do it every couple of years as I can get caught in the rain from time to time but when you find that you are adjusting your shifting far too often to be associated with cable stretch its time to replace them. As for the adjuster, I find that when Installing new cables its hard to get it completely taut initially so I leave it all the way undone so that way I can unscrew it to add tension where necessary to achieve desired shifting. As others have said too, it sounds like your shifting problem from your update is due to gummed up with road grime and old broken down lubricant. Periodically I shoot mine with wd 40 and then use 3 in 1 oil as a final touch as wd40 is great for flushing stuff out, but is not designed to be a long term lubricant. I also like to drop some oil or Teflon base lubricants into my cables from time to time to make sure they are not sticking in the housings.

  11. #11
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    Quote Originally Posted by bsker View Post

    Either way, I think I also have a separate issue that makes adjustment difficult - I believe that one of derailleur plates is bent. Is there a place to buy parts for derailleurs without having to buy the entire derailleur itself?
    That almost certainly isn't helping. Generally you can't get replacement components for derailleurs, certainly not Shimano ones. Furthermore, while the inner plate of the RD can usually be removed simply by undoing the two pulley bolts, the outer plate may be attached to the derailleur body with a rivet or with a circlip that may well be a PITA to get at and remove. I'd suggest replacing the derailleur. Since Rapid Rise is part of the derailleur design, unless you can find a replacement Rapid Rise derailleur it'll shift the way most derailleurs do, and the two motions for shifting up and shifting down will swap round.

    Regarding the barrel adjusters, yes, that's what I'm saying. If you have Rapid Rise shifters, then your understanding of what you need to do with the cable is correct. I'd just use the shifter's barrel adjuster if I were you, I'm not sure if the fitting for that pulley thing you've got is designed to be used while partially unscrewed from the derailleur body, and appears to have been fitted as a replacement to the adjusting barrel the derailleur would normally have.
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