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  1. #1
    Senior Member matimeo's Avatar
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    Sora front derailleur hard shifting

    Note: This issue finally got resolved, mostly on page two. Jump ahead- turns out this bike comes with the wrong size bottom bracket (113mm that it comes with creates a too large chain line and poor front shifting due to excess cable tension). Nashbar has agreed to send me a 108mm bottom bracket, which should resolve the problem.


    I just got a Nashbar CX1 cyclocross in the mail today and was setting it up for the wifey. I needed to make some adjustments to the front derailleur, and this bike sports the Sora 3500 2x10 sti group. I made sure and adjusted the cable tension correctly (since I know too tight could cause problems). I'm pretty sure I got it right, since there's only enough tension to comfortably get the chain onto the large ring with the high limit screw removed. When I downshift to the small ring, it seems to make a very loud sound and make a fairly rough shift. I took a video of it, but I don't know how well it represents the sound and obviously you can't feel it. Is this a defective shifter, or am I missing something else? Cable routing and everything else appears to be normal. I own a bike with 105 brifters, and once owned a bike with Sora but it was stolen from me almost immediately, so I don't recall the shift quality.

    Last edited by matimeo; 09-01-14 at 11:05 AM.

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    Let's start with the basics.

    High limit set to the loosest setting that prevents over shifting and dumping the chain. Test by pulling the cable directly rather than with shift lever.
    Low limit set for best trim on inner ring and inner most rear sprocket. Should be so the inner cage barely clears (never rubs), allowing maximum room for the outer plate to accommodate the outer cassette sprockets (won't accommodate all without rubbing)
    Cable/trim as slack as possible yet still giving good upshifting with cage ending so outer plate just clears chain in high.

    If all is as above, there should be room to move the FD out a bit beyond where it's resting in high. In other words it shouldn't be resting against the outer limit.

    There is very little control on the downshift because you're releasing the cable and the FD spring is in control, but you can get a smoother shift if you ease up on the pedals to keep chain tension low. If you delay the downshift until you have no choice, the higher chain tension makes for a harsh sudden shift and possible chain drop.

    Try the above and see if it helps.
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  3. #3
    Senior Member Retro Grouch's Avatar
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    Does that derailleur have a little tab near the cable anchor point? If so, the cable is supposed to route OVER that tab.
    My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.

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    Andrew R Stewart Andrew R Stewart's Avatar
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    I find that the height of the cage WRT the large ring's teeth tops, is a factor in rough or smooth shifting. Sometimes only a couple more MMs of clearance can make a large difference.

    Also I am unsure what is actually being referred to as "When I downshift to the small ring, it seems to make a very loud sound and make a fairly rough shift. I took a video of it, but I don't know how well it represents the sound and obviously you can't feel it. Is this a defective shifter, or am I missing something else" might mean the der is making the sound and feels rough or the shifter is. I tried to open the video link w/o success.

    Francis' suggestion to use the cable tug to shift while adjusting the der is a very good technique to try. I do this often at work. Andy.

  5. #5
    Senior Member matimeo's Avatar
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    I updated the link to the video in my original post. Here's the link as well: https://www.youtube.com/watch?v=cTLq...ature=youtu.be

    Retro Grouch, I don't think I see the tab you're describing- everything looks correctly routed.

    FBinNY, I've followed those guidelines and everything is correct.

    It just seems like I have to push really hard on the shifter and it makes an pretty loud and hard clunk when it drops- not so smooth. Seems like something's wrong.

    What do you think after seeing the video?

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    I think you should get in-person assistance - bike co-op, knowledgeable friend or (horrors) a local bike shop.
    There's no such thing as a routine repair.

    Don't tell me what "should" be - either it is, it isn't, or do something about it.

    If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

    Please take the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

  7. #7
    Senior Member matimeo's Avatar
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    Quote Originally Posted by cny-bikeman View Post
    I think you should get in-person assistance - bike co-op, knowledgeable friend or (horrors) a local bike shop.
    Blasphemy. It feels like the cable is too tight, but it isn't any tighter than it needs to be to just get it up to the big ring. I'll have to keep playing around with it. Thanks for your thoughts.

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    Quote Originally Posted by matimeo View Post
    Blasphemy. It feels like the cable is too tight, but it isn't any tighter than it needs to be to just get it up to the big ring. I'll have to keep playing around with it. Thanks for your thoughts.
    You earlier mentioned that you had the outer limit adjusted all the way out. Take a minute to confirm that the FD has over travel beyond where it sits when you let go. Do so by tweaking the wire at the downtube. If the FD doesn't have over travel available and is up hard against the outer stop, the added tension in the cable will cause the "burst dam" hard shift.
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  9. #9
    Senior Member matimeo's Avatar
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    Quote Originally Posted by FBinNY View Post
    You earlier mentioned that you had the outer limit adjusted all the way out. Take a minute to confirm that the FD has over travel beyond where it sits when you let go. Do so by tweaking the wire at the downtube. If the FD doesn't have over travel available and is up hard against the outer stop, the added tension in the cable will cause the "burst dam" hard shift.
    OK, this is making sense actually, so let me clarify what you're saying. When you say, "confirm that the FD has over travel beyond where it sits when you let go", do you mean that the FD should have some travel beyond what is needed to have it on the big ring (further to the right as you look down while standing over the bike)? If this is what you're saying, it would almost seem to indicate that I need to tighten the cable more to give it more outward travel. Am I understanding correctly?

  10. #10
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    Quote Originally Posted by matimeo View Post
    OK, this is making sense actually, so let me clarify what you're saying. When you say, "confirm that the FD has over travel beyond where it sits when you let go", do you mean that the FD should have some travel beyond what is needed to have it on the big ring (further to the right as you look down while standing over the bike)? If this is what you're saying, it would almost seem to indicate that I need to tighten the cable more to give it more outward travel. Am I understanding correctly?
    No, tightening the cable is the last thing you want to do. Start by backing off the high limit screw for a moment, then adjust the cable for good trim, and shifting using the outer limit to ONLY prevent overshifting and dumping the chain to the outside. The outer limit position is tested by dirct pulling on the cable at the down tube, not via the lever.

    When perfectly adjusted the FD will shift and trim correctly hanging on the cable, but not resting against the outer limit stop.

    BTW- I took a look at the video, in which you cleverly positioned the handlebars to prevent someone from seeing the FD from the critical front view.

    But, I didn't notice any movement when you did the trim click. That's the best evidence that your cable is adjusted too tight. If it's that tight and the FD isn't moving farther out on the main click, and falling in a bit with the trim click, it can ONLY be because the limit is set too far in.

    Think of the limit stop as a concrete barrier keeping you from driving off the side of a bridge. The cable does what the driver does staying in the center of the lane. You don't drive a car rubbing down the barrier, and likewise shouldn't have the FD up against the stop.

    What you're doing is moving the barrier into the lane, narrowing it so you can't stay in lane with out rubbing. Move the barrier out of the lane, and use it only to stay out of the drink, and the rest is easy.
    Last edited by FBinNY; 08-21-14 at 12:30 PM.
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  11. #11
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    Quote Originally Posted by matimeo View Post
    Blasphemy. It feels like the cable is too tight, but it isn't any tighter than it needs to be to just get it up to the big ring. I'll have to keep playing around with it. Thanks for your thoughts.
    It's blasphemy to get in-person assistance, but perfectly OK to take three times as long to get help from strangers who can't see, feel or hear the problem, and "playing around with it" on your own. I don't get it. Do you imagine that by getting help on the Internet you're still doing it on your own?
    There's no such thing as a routine repair.

    Don't tell me what "should" be - either it is, it isn't, or do something about it.

    If you think I'm being blunt take it as a compliment - if I thought you were too weak to handle the truth or a strong opinion I would not bother.

    Please take the time to post clearly so we can answer quickly. All lowercase and multiple typos makes for a hard read. Thanks!

  12. #12
    Senior Member matimeo's Avatar
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    Quote Originally Posted by cny-bikeman View Post
    It's blasphemy to get in-person assistance, but perfectly OK to take three times as long to get help from strangers who can't see, feel or hear the problem, and "playing around with it" on your own. I don't get it. Do you imagine that by getting help on the Internet you're still doing it on your own?
    Sorry, I was being sort of sarcastic and stereotypically male. I know that doesn't always get picked up via the internets. I guess I was also playing off of your use of the word "(horrors)", which I assumed you were using sort of sarcastically.

    However, by nature I will try to "play around with it on my own" for longer than I should. I guess in my mind taking it to the bike shop would take all of the fun out of it.
    Last edited by matimeo; 08-21-14 at 03:39 PM.

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    Quote Originally Posted by cny-bikeman View Post
    It's blasphemy to get in-person assistance, but perfectly OK to take three times as long to get help from strangers who can't see, feel or hear the problem, and "playing around with it" on your own. I don't get it. Do you imagine that by getting help on the Internet you're still doing it on your own?
    Chill.

    I suspect the OP's "blasphemy" was in the vein of "real men don't ask directions" (or eat quiche).

    In many minds there's a world of difference between paying a pro to do something, and trying to DIY with or without help from kibbitzers and strangers via the net. I'm sure that at some point the OP will have an epiphany, discover where's going wrong and solve his problem, or give up, kick his dog and bring the bike to the bike shop.

    To the OP, I'm convinced that your problem is excess cable tension. Note that in normal use, even though people say "adjust cable tension", we never actually do that. The tension is determined by the spring, and doesn't ever change. So if you find you have or need more cable tension when you shift to high, it's because you're forcing the FD against some resistance, most likely a lemit screw cranked down too far.
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    Based on nothing more than the sound on the video I think the cable is too tight. And when the shifter releases enough cable to make the down shift you're getting some elastic rebound that is "sort-of" throwing the chain down on the inside ring.

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    Senior Member Wilfred Laurier's Avatar
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    Quote Originally Posted by FBinNY View Post
    To the OP, I'm convinced that your problem is excess cable tension. Note that in normal use, even though people say "adjust cable tension", we never actually do that. The tension is determined by the spring, and doesn't ever change. So if you find you have or need more cable tension when you shift to high, it's because you're forcing the FD against some resistance, most likely a lemit screw cranked down too far.
    Quote Originally Posted by Retro Grouch View Post
    Does that derailleur have a little tab near the cable anchor point? If so, the cable is supposed to route OVER that tab.
    fd
    as rg said
    the cable needs to go over the tab
    and if it is routed under the tab
    the tension in the cable will be higher than normal
    because misrouting effectively shortens the arm on which the cable is pulling

  16. #16
    Senior Member matimeo's Avatar
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    Quote Originally Posted by Wilfred Laurier View Post
    fd
    as rg said
    the cable needs to go over the tab
    and if it is routed under the tab
    the tension in the cable will be higher than normal
    because misrouting effectively shortens the arm on which the cable is pulling
    I presume this is the correct routing of the cable- I can't imagine it should go on the other side of that tab- that would really be out of the way.

    20140823_172815.jpg20140823_172808.jpg20140823_172754.jpg

  17. #17
    Senior Member matimeo's Avatar
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    So, thanks to all for their replies. The idea that the cable is too tight makes the most sense to me, however, I can't figure out the following:

    1. Even if I take the outer limit screw completely out, then set the lower trim, then tighten the cable only enough so that I can get the chain to the big ring, it still shifts very hard. (this is how I've adjust hundreds of front derailleurs in the past, never had this problem before).

    2. I don't think it's in the shifter mechanism itself, because if I remove the cable from the pinch bolt and shift while pulling on the cable, it isn't so rough.

    3. If I loosen the cable some, I notice that I can sometimes get to the big ring, and even far enough out to not rub in the highest gear while I'm holding the lever, but it won't stay in that position when I let go unless I tighten the cable more. Is that an indication of a bad front derailleur?

    I'm still scratching my head on this. I pulled out my bike with 105 components and it wasn't rough like this at all. I know it's better quality, but something is definitely off, and I can't put my finger on it with conventional wisdom.

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    OK, let's eliminate one possibility. Back off the outer limit screw all the way, and pull the gear wire away from the frame like a bow string while turning the crank. The chain should go over the top of the outer ring and dump to the outside. If it doesn't dump, then it seems that your FD lacks enough throw for the distance from the mount to the chainring.

    Do the test, and post the result, then we'll try the next step accordingly.
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  19. #19
    Andrew R Stewart Andrew R Stewart's Avatar
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    Now that I've looked at the video I don't see any cage movement from the large ring trim function. As others have said this happens when the cable is too tight. If you loosen the cable's anchor bolt, run the cable adjuster to about half way through it's range then retighten the cable and anchor bolt you now have a lot of adjuster range to try many cable tensions (or casing lengths). Andy.

  20. #20
    Senior Member matimeo's Avatar
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    Quote Originally Posted by FBinNY View Post
    OK, let's eliminate one possibility. Back off the outer limit screw all the way, and pull the gear wire away from the frame like a bow string while turning the crank. The chain should go over the top of the outer ring and dump to the outside. If it doesn't dump, then it seems that your FD lacks enough throw for the distance from the mount to the chainring.

    Do the test, and post the result, then we'll try the next step accordingly.
    It has enough throw- I've tried this and I don't have any trouble getting to the big ring.

    Quote Originally Posted by Andrew R Stewart View Post
    Now that I've looked at the video I don't see any cage movement from the large ring trim function. As others have said this happens when the cable is too tight. If you loosen the cable's anchor bolt, run the cable adjuster to about half way through it's range then retighten the cable and anchor bolt you now have a lot of adjuster range to try many cable tensions (or casing lengths). Andy.
    The trim function works fine. A little rough, but it works just fine. I've done what you said about adjusting the cable adjuster half way, then setting the cable tension- so I can tighten it (with the limit screw off) until it just barely goes far enough out to get the chain on the big ring without rubbing, but then I'm back to clunky downshifts.

    Perhaps my next move is to sit on a different bike with Sora components and see if this is simply normal. If that's the case, I wonder what would make the biggest difference in improving the smoothness of shifting: upgraded brifters or an upgraded FD? My guess is upgraded brifters, since the FD doesn't do much but move where it's told.
    Last edited by matimeo; 08-23-14 at 08:51 PM.

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    Quote Originally Posted by matimeo View Post
    It has enough throw- I've tried this and I don't have any trouble getting to the big ring..
    Getting to the big ring is not the issue. With the limit screw backed out or removed, CAN YOU EASILY THROW THE CHAIN OVER THE BIG RING AND DUMP IT TO THE OUTSIDE?????

    If not, then THAT is the problem. The crank is beyond the working travel range and you need to force the chain up with excess cable tension.

    As I posted way back when, in a correctly adjusted FD the derailleur settles back a hair after completing the shift and eases the cable tension. You're doesn't because there's no over travel, and you cannot shift without jamming the FD fully up hard against whatever is stopping it. Earlier I gave you a bridge barrier analogy. Your barrier is crowding the lane, and the cannot drive the lane without scraping the barrier.

    Sorry for the bold full caps, but I'm trying to get you to see the point. Please reread my earlier posts, Nos. 2, 8 & 10 until you understand what I'm describing, and then tell us whether the FD has enough travel to dump the chain to the outside or not.
    Last edited by FBinNY; 08-23-14 at 09:55 PM.
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  22. #22
    Senior Member matimeo's Avatar
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    Quote Originally Posted by FBinNY View Post
    Getting to the big ring is not the issue. With the limit screw backed out or removed, CAN YOU EASILY THROW THE CHAIN OVER THE BIG RING AND DUMP IT TO THE OUTSIDE?????

    If not, then THAT is the problem. The crank is beyond the working travel range and you need to force the chain up with excess cable tension.
    Hey, no worries on the caps. Just glad you're trying to help me understand. So I did as you said, pulling on the cable like a guitar string with the outer limit screw removed and it definitely does not have nearly enough pull to dump the chain on the outside. In fact, it barely has enough to not rub when the rear cassette is in the last outside gear. So essentially you're right, the problem may lie in the fact that the FD doesn't have enough travel to get to where it needs to be without having excess tension on it. So now what?

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    Quote Originally Posted by matimeo View Post
    Hey, no worries on the caps. Just glad you're trying to help me understand. So I did as you said, pulling on the cable like a guitar string with the outer limit screw removed and it definitely does not have nearly enough pull to dump the chain on the outside. In fact, it barely has enough to not rub when the rear cassette is in the last outside gear. So essentially you're right, the problem may lie in the fact that the FD doesn't have enough travel to get to where it needs to be without having excess tension on it. So now what?
    OK, we now know the problem, so there are options. The first is to see if it's possible to move the right crankset inboard 2-3mm. Step one is to see if there's clearance between the rings and the chainstay. Then if so, depending on the type of crank and BB, this may mean a shorter spindle,fl oating a cartridge to the left, transferring a spacer from the right to the left side.

    If the crank can't move in, for whatever reason, then we'll try to move the FD out. Sometimes it calls for a new FD, other times a moun ting bracket can be shimmed, and on braze-ons sometimes some skilled filing does the trick. Or you can look at the FD and determine exactly what is limiting it's motion. In many cases, there's some material that can be removed to advantage, so that's one more option.

    Of course, the last option is to replace the FD with one with more throw.

    But, in most cases it boils down to the chain line or moving the crank inboard.

    BTW- you can measure the chainline by measuring from the down or seat tubes, to the middle of the gap between the ring (eyeballing the exact center is good enough), then adding the radius of that tube. This should be less than 44mm or so. (see Sheldon Brown on Chainline for more info).

    So, armed with what you need to do, you are now more than halfway to fixing this. Hopefully without 23 more posts or any full caps.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

  24. #24
    Senior Member matimeo's Avatar
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    I've been trying to google this since realizing this is the problem. I don't see anything that says this is a common problem with the Sora 3500 FD. I've never had this issue before, so I'm curious why a bike would be set up that didn't work like this. Do I have any recourse to just have Nashbar send me a new FD?

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    Quote Originally Posted by matimeo View Post
    I've been trying to google this since realizing this is the problem. I don't see anything that says this is a common problem with the Sora 3500 FD. I've never had this issue before, so I'm curious why a bike would be set up that didn't work like this. Do I have any recourse to just have Nashbar send me a new FD?
    It's probably not a derailleur problem. Odds are it's a chainline problem. Do the chainline measurement I suggested (read Brown on Chainline), and see if you have excess chainring/chainstay clearance. Minimum would be 1-2mm, any more is excess.

    You only need to buy yourself 2mm to make this work, and I'm sure it's there to be found someplace.

    Stay with me, I got you here, let me help you get the rest of the way. Since I can't be there I need you to make the measurements, or do the tests I'd have done if I had the bike in front of me.
    FB
    Chain-L site

    An ounce of diagnosis is worth a pound of cure.

    “Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

    “One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

    WARNING, I'm from New York. Thin skinned people should maintain safe distance.

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