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  1. #1
    WEK
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    Shifts skipping on the new KHS w/ 105. Adjustment problem, I assume?

    Loving the new bike (KHS 747)...except for a recent development. It's skipping gears when it shifts, sometimes it won't shift at all when I hit the lever and then 30 seconds later it suddenly shifts out of nowhere when I'm not hitting the lever (the "very late shift"). Sometimes it shifts even when I haven't hit the lever at all (I like to call this the "ghost shift").

    I assume it's just an adjustment problem and I know the LBS will handle it. I'm just curious if anyone else runs into this and if anyone with more experience has an idea what causes it? I've been taking good care of the drivetrain with regular cleaning and lube. And it hasn't undergone any trauma and has less than 1,000 miles on it. Also curious whether continuing to ride while it's doing this (can't get into the LBS until later this week) is a problem?

    As always, thanks in advance for the help. This forum is great. I who am about to learn salute you.

  2. #2
    SuperGimp TrojanHorse's Avatar
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    Typically... your components will settle in as they get used, so what was previously a perfectly adjusted cable probably needs a little tweaking. Some people call it cable stretch but yes, your solution is likely a simple adjustment of the barrel adjuster back by the rear derailleur. Things to think about when riding - when you shift, does your drive train like to go UP to a larger cog or DOWN to a smaller cog? If your cable is a tad loose, your shifter will be reluctant to shift up, and you can turn that barrel adjuster a few clicks counter clockwise to compensate. (it's threaded, so turning it clockwise will turn the barrel INTO the RD, turning it counter clockwise will turn it OUT of the RD, which will have the effect of tightening the cable)

    You can also get behind your bike and check out where the RD lines up the chain - is it perfectly lined up? If it's sort of between two cogs you may get the ghost shifting you're talking about.

  3. #3
    WEK
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    Quote Originally Posted by TrojanHorse View Post
    Typically... your components will settle in as they get used, so what was previously a perfectly adjusted cable probably needs a little tweaking. Some people call it cable stretch but yes, your solution is likely a simple adjustment of the barrel adjuster back by the rear derailleur. Things to think about when riding - when you shift, does your drive train like to go UP to a larger cog or DOWN to a smaller cog? If your cable is a tad loose, your shifter will be reluctant to shift up, and you can turn that barrel adjuster a few clicks counter clockwise to compensate. (it's threaded, so turning it clockwise will turn the barrel INTO the RD, turning it counter clockwise will turn it OUT of the RD, which will have the effect of tightening the cable)

    You can also get behind your bike and check out where the RD lines up the chain - is it perfectly lined up? If it's sort of between two cogs you may get the ghost shifting you're talking about.
    Much appreciated, thanks. It hates to go up to a larger cog (easier gear). That's where nearly all the missed shifts and gear skips happen. The ghost shifting, interestingly enough, always goes to a smaller cog (harder gear). It happened twice on climbs--I'm not sure I've ever been that angry at an inanimate object.

  4. #4
    SuperGimp TrojanHorse's Avatar
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    Quote Originally Posted by WEK View Post
    Much appreciated, thanks. It hates to go up to a larger cog (easier gear). That's where nearly all the missed shifts and gear skips happen. The ghost shifting, interestingly enough, always goes to a smaller cog (harder gear). It happened twice on climbs--I'm not sure I've ever been that angry at an inanimate object.
    Check out this video, and ignore the instructions before 1:20 (they're really more for a new RD installation, but they're informative) and especially pay attention when he's talking about indexing at about 2 min. through 3 min. Pretty good visual representation of what I'm talking about.



    Your B-screw, upper and lower limits are PROBABLY set correctly already, but you can double check it. My guess is a few judicious turns of that barrel adjuster will fix you right up with no visit to the LBS required.

    Any time you fiddle with the RD, there are a few things worth checking when you're done.
    1) make sure you can shift to all your gears (I've adjusted the cable tension high enough so that I couldn't get to the last small cog before. Ha)
    2) make sure you can NOT shift so far that you touch any spokes with your RD.
    3) make sure the cable is tightly attached (shouldn't move in the fixing bolt, it's probably fine)
    4) go for a short test ride and shift through all your gears and make sure things work correctly.

  5. #5
    WEK
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    Quote Originally Posted by TrojanHorse View Post
    Check out this video, and ignore the instructions before 1:20 (they're really more for a new RD installation, but they're informative) and especially pay attention when he's talking about indexing at about 2 min. through 3 min. Pretty good visual representation of what I'm talking about.



    Your B-screw, upper and lower limits are PROBABLY set correctly already, but you can double check it. My guess is a few judicious turns of that barrel adjuster will fix you right up with no visit to the LBS required.

    Any time you fiddle with the RD, there are a few things worth checking when you're done.
    1) make sure you can shift to all your gears (I've adjusted the cable tension high enough so that I couldn't get to the last small cog before. Ha)
    2) make sure you can NOT shift so far that you touch any spokes with your RD.
    3) make sure the cable is tightly attached (shouldn't move in the fixing bolt, it's probably fine)
    4) go for a short test ride and shift through all your gears and make sure things work correctly.
    Will do. Thanks!

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    Here's another video that explains how the system works. I agree though, all you probably need to do is turn the barrel adjust on the rear derailleur a couple of turns counter-clockwise. 5700/6700/7900 can sort of drive you crazy with minor adjustments trying to get it perfect.

    https://www.youtube.com/watch?v=SkzvfCaIbyQ
    Last edited by Dunbar; 05-06-14 at 03:59 PM.

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    Quote Originally Posted by WEK View Post
    Much appreciated, thanks. It hates to go up to a larger cog (easier gear). That's where nearly all the missed shifts and gear skips happen. The ghost shifting, interestingly enough, always goes to a smaller cog (harder gear). It happened twice on climbs--I'm not sure I've ever been that angry at an inanimate object.
    Sounds like you need to increase the tension on the cable that goes to the rear derailleur. There's often a barrel-adjuster where the cable enters the RD or, sometimes, up near the head tube. If the bike shifted perfectly when new, it's not unexpected for the cables to stretch or slip a bit. Turn the adjuster counter-clockwise to increase tension on the cable.

  8. #8
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    Why do some bikes have multiple barrel adjusters for the derailleurs? My Trek has a barrel adjuster on the upper part of the downtube cable stop and right on the 105 RD just as in the video? The do the same thing - shorten or lengthen (change tension) the cable, don't they?
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  9. #9
    SuperGimp TrojanHorse's Avatar
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    Quote Originally Posted by RoadTire View Post
    Why do some bikes have multiple barrel adjusters for the derailleurs? My Trek has a barrel adjuster on the upper part of the downtube cable stop and right on the 105 RD just as in the video? The do the same thing - shorten or lengthen (change tension) the cable, don't they?
    Well, there's no barrel adjuster at the FD, so you need that one, and if you care to adjust your RD while riding, it's hard to reach all the way down there.

  10. #10
    just pedal donalson's Avatar
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    it sounds like these guys have it fairly well covered... sounds like basic cable stretch and a few turns of the cable tension adjuster should get you sorted.

    not all rear derailleurs have the adjuster either... my MTB rear doesn't... but in reality I think it has more to do with the fact that it allows riders to make minor adjustments while riding... it's a lot easier to reach the downtube than the rear derailleur lol... higher end shimano cable stops even have a bit of a "wing" on it making it easier to tweak while riding.
    mtbr clyd moderator

  11. #11
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    Amazing.

    I just discovered a week ago that I could adjust the FD a little while riding because of the barrel adjuster locations. Thought to myself, "gee, that's a convenient surprise..." and having no clue it's in the design or that other cyclists would actually have to adjust while riding. Thanks TrojanHorse and Donalson for bringing the obvious to light. I'm amusingly embarrassed...
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  12. #12
    Senior Member daviddavieboy's Avatar
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    I just bought a new bike last month with 105. Shifting was out after 100 miles or so.

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    When purchased new from the LBS via my ride home, my Shimano 105 equipped 2011 Trek 2.1 road bike dropped the chain to the inside when attempting to drop to its 30 tooth granny chainring and the chain skipped twice on the rear cogs both times I attempted to pedal out of the saddle on two different ascents. Needless to say, I was less than amused after spending a decent sum of money. Even my base model 2012 Trek Wahoo 29er hardtail shifted flawlessly from new.

    After starting from scratch upon arriving home with my new 2011 Trek 2.1 road bike, I quickly got its front and rear derailleurs adjusted to shift smoothly and reliably. They’ve been working fine ever since.

  14. #14
    coprolite fietsbob's Avatar
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    hyperglide tooth profiles are eager to shift, some times when yo wish it wouldn't.

  15. #15
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    KHS 747 Flite Owners with skipping chain/shifts:

    I am seeing other owners of 2014 KHS Flite 747's on this forum complaining of the same "skipping chain/shift" problem I experienced with mine.

    I have your solution.

    I ordered and picked up my KHS 747 Flite XXXL bike last month and immediately on the first ride the chain skipped mysteriously when giving the extra long 200mm cranks some forward pressure to pedal. I could lightly pedal with no skipping, but any real pressure on the pedal- even moderate- made the chain "skip forward violently". I realized this only happens when on the 52 tooth front big chainring. It never skipped while on the small 36 tooth front inner chainring. My LBS tried all sorts of adjustments to the front and rear derailleurs plus adjusting the barrel adjusters and even tightening the crank arms. It still skipped. We then put another KHS Flite 747 chainring on my bike that was on another new Flite 747 XXL in the showroom- SAME problem- skipping chain.

    Here is the defect and the solve: The issue is that the big 52 tooth front chainring KHS installs is far too weak for us Clydesdales-period. When putting pressure to pedal the big chainring "bends" and lets the chain pop off the chainring and jump a tooth- rather violently. My LBS then switched the KHS chainring to a bone stock Shimano 50 tooth big chainring and I had no skipping at all- I could even stand on the cranks with all my weight- perfect!

    Here is my permanent solve at my own expense- I bought new forged 52/36 chainrings from Praxis Works (about $165). Forged chainrings are the strongest for us Clydesdales and Praxis is the only (yes only) manufacturer of a 52/36 forged compact 110BCD chainring set in the world- I know because I did many hours of research to find this out! Shimano is the only other maker of forged chainrings in the world, but only makes a 50/34 Ultegra combo, not a 52/36. I installed the Praxis 52/36 forged chainrings on my Flite and it is sheer perfection. The shifts are perfection and I can stand on the cranks and have zero chainring flex. The 50/34 Shimano Ultegra combo will work perfect BTW if you want a setup better for hill climbing- you will just need to have your front derailleur adjusted and moved a little lower on the frame to accommodate the smaller diameter.

    So, KHS seems to have sourced very cheap chainrings for these "Clydesdale-specific" bikes. I took it upon myself to fix the issue and don't want to point fingers at them. Heck, I am just glad I was able to find a bike for my 6 foot 8 body! KHS should take note though and just ship these with better chainrings- probably 50/34's as the smaller diameter will be even stronger. Yes, It would be ideal if they installed forged chainrings for us bigger folk, but that would add $100-$150 to the price. As I proved, even a mid-range Shimano 50 tooth stamped chainring was better than the stock KHS chainring.

    So, if you bought a 2014 KHS Flite 747- change out the chainrings- both if you can afford a new forged set, but at least replace the 52 tooth stock one with a 50 tooth "standard" chainring. When I had the Shimano 50 tooth and the KHS 36 tooth combination on while waitng for my Praxis chainrings it seemed to shift just fine. If you cant afford that, have your LBS change the 52 tooth to a stronger 50 tooth and have them file a warranty claim with KHS ad they should really cover your switch to a stronger chainring. I am not sure you can find a 52 tooth "stamped/machined" chainring strong enough to handle our weight as the extra diameter is what may be causing the flex. If you want to stick with the 52/36 stock setup like I did go with the forged 52/36 Praxis forged- they are strong and don't bend! This is NOT a commercial for Praxis- frankly I wish I did NOT have to spend my money to fix KHS's problem, but i wanted you all to know how I got my Flite shifting perfectly!

    Problem Solved!

    Good Luck All!
    Last edited by svosho; 05-21-14 at 04:13 PM.

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