Shimano front derailleur and internal cable routing

Discussion in 'Cycling Equipment' started by jojoma, Mar 7, 2014.

  1. jojoma

    jojoma New Member

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    I am riding my first internal cable frame (Specialized Tarmac SL4) I have Ultegra 6800. The front shifting is very solid, but I noticed that in the 53/11 or 53/12, the chain rubs a bit on the FD. Because there are no barrel adjusters with this internal cable setup, I can't increase the cable tension, which would move the FD out a touch. The FD does have the ability to move further outward (when I play with it with my hands, for instance) so I don't think this is something that can be fixed with a limit adjustment.

    It's not a huge deal, as I am not in these big gears often. It just seems that with all of the benefits of the new Shimano FDs, this is one of the negatives. Anyone else have such an issue?
     
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  2. dhk2

    dhk2 Active Member

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    Doubt your problem ist a function of the design of the new FD. Believe you just need to adjust the cable tension. If you don't have any adjusters in your cables, no big deal. Shift down to your small ring, loosen the cable at the FD, pull up the cable to remove the slack and lightly tension it, and retighten the pinch bolt. Make sure you keep the cable routed the same way over the FD arm.

    My bike was custom-built, and the builder didn't like to use cable adjusters on the downtube. He said I wouldn't need them, they made the bike look like it came from a discount store, and it was just more junk on the frame to corrode. In the 10 years I've owned it, have only adjusted the FD cable after the first 500-1000 miles when replacing the cable and housing....which I've done twice now.
     
  3. urge2kill

    urge2kill Member

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    Same problem. I stuck a CD case inbetween the front derailleur (FD) and the frame while adjusting cable tension.

    I wasn't precise since I only shift the rear derailleur. This guy used "fueler gauges [sic]".

    [​IMG]
     
  4. oldbobcat

    oldbobcat Well-Known Member

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    Guys, Shimano 6800 and 9000 front derailleurs are a very different animal, with more ways to screw up, and there aren't many riders or shop mechanics with a whole lot of experience with it yet.

    I'm going to consult with my colleagues before offering any advice. In the mean time, you might just want to take the bike back to the dealer and say, fix it. Or you can set your browser to this page, http://si.shimano.com/#seriesList/38, scroll down to the heading FD-6800, and download the front derailleur dealer manual, under DM, and see if the dealer did everything right. I'll get back to you Monday evening.
     
  5. urge2kill

    urge2kill Member

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    I apologize. I don't have an internal cable frame. [​IMG]
     
  6. oldbobcat

    oldbobcat Well-Known Member

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    The problem with all cables is that the housings settle into the ferrules after you install them, so even after the mechanic runs through the gears after he's built the bike, the cables will "stretch," both while he's still working on the bike and then while the bike sits on the sales floor. And then they'll "stretch" some more after the customer takes it for a ride.

    With externally routed cables, the mechanic can "bowstring" the cables, which seats the housings firmly. With the cables inside the frame, there's nothing to grab.

    Rather than run the risks of fraying the cable or damaging the shifter while trying to make adjustments, I'm going to just recommend taking it back to the dealer so he can review the installation, put a barrel adjuster on the cable, and get it adjusted right. Adjusting cable tension on a new bike without a barrel adjuster is just something a newbie should not attempt or be required to do.
     
  7. alfeng

    alfeng Well-Known Member

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    THERE YOU HAVE IT!

    The "problem" (if one wants to finally agree that there is one) with cable "stretch" (which is REALLY housing compression) is more-than-likely the consequence of using parallel stranded cable housing + ferrules ...

    As I have said before, I thought parallel stranded cable housing had been abandoned in the late-70s/early-80s, so it was a surprise to ME when (due to my possible inattention) when Shimano resurrected it with their STI road shifters ...

    WHY put up with the hassle if one doesn't have to?

    THAT problem can be all-but-eliminated by using coiled brake cable housing [or, NOKON or AZTEC housing if you have the extra money burning a hole in your pocket] ... coiled brake cable housing was my previous recommendation AND remains my current recommendation for derailleur cables which many people cannot seem to wrap their minds around due to the label ascribed to the larger inner diameter, coiled cable housing ...

    THAT's "okay" ... there are things which other people espouse which 'I' can't wrap my mind around.

    FWIW. The simplest solution to the front derailleur shifting problem is always to simply replace the Shimano shifters with Campagnolo shifters -- front & rear ... But, if you are a sponsored rider who does not have a choice OR if someone is amongst those who insist on using Shimano-or-SRAM shifters instead of Campagnolo shifters for other reasons ...

    THEN, presuming that you are NOT using the wrong chain, consider adjusting the front derailleur's INNER STOP outward by a smidge (of course, ensure that the chain will still transfer from the outer to the inner Chainring when you want it to!!!!) ...

    Re-tension the cable ...

    Test ...

    Adjust, again ...

    Test ...

    DONE!?!
    BTW. In the past, Kestrel frames lacked inline derailleur cable adjusters, too. I don't know what their current frames look like ... If you agree with dhk2's frame builder that cable adjusters make the frame look cheap (to each his own as far as aesthetic sensibilities or real world practicality -- I have frames which are with & without AND I am glad that they are present on my over-priced frame and annoyed that they are not present on the less expensive frames), then SPLIT the cable housing before it reaches the frame & insert a cable adjuster someplace less visible. Regardless, I agree with oldbobcat that you should consider bringing it back to the shop & having them sort out the problem (which may result in an inline adjusters being added to the frame) if you are reluctant make the transition to Campagnolo shifters!
     
  8. oldbobcat

    oldbobcat Well-Known Member

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    Parallel (rope) stranded housings don't compress so much as settle into the ferrules. After settling occurs, rope stranded housings are considered by Shimano and SRAM to be more dimensionally stable, but they are also weaker, which makes them prone to delaminating under high loads. That is why they are used for shift cables but not brake cables. High loading usually occurs when a cable is routed incorrectly, a shifter or derailleur is broken, or an old cable rusts inside the housings. Delaminating also occurs when the housings get old and crusty. Properly sized ferrules are also absolutely required to prevent the ends from splitting.

    Alf and I disagree about this. Use your own judgement. I've been using rope stranded shift housings with Shimano and SRAM drivetrains without problems since 2006, when I finally bought my first new bike in 25 years. Shimano specs two grades of high-grade (and expensive) coated low-friction cables and (rope stranded) housings for their mechanical 11-speed systems. They researched this product extensively.

    Regarding barrel adjusters, like Alf, I recommend them for everyone who does not have a team mechanic who can replace cables every other week. They preserve cable life by minimizing dinking around with the cable fixing bolt. On bikes with internal routing, they can only be installed by splitting housing somewhere between the handlebar and the frame. The best place to split is far enough from the frame so it doesn't scratch the finish and where the cable appears to be the straightest.
     
  9. alfeng

    alfeng Well-Known Member

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    FWIW. I generally love Shimano's engineering & manufacturing thereof + I love Shimano's customer service ...

    • BTW. Parallel stranded (rope stranded!?!) cable housing certainly predates Shimano ... certainly, by decades ... possibly by 100+ years ... that is, I suspect that some form of parallel stranded cable housing originated somewhere near the dawn of the Industrial Revolution! No doubt, a variation of a rifled pipe-or-(gun)-barrel.
    • As I previously noted, I thought that the use of parallel stranded cable housing for bicycles had been abandoned in the late 70s or early 80s, but I guess that what 'I' consider to be a bad idea just won't go away!

    Regardless, lest we forget, Shimano also extensively researched non-concentric motion & gave us the quasi-elliptical BioPace chainrings + their half-brother -- the eccentric take-up spools on their STI Road shifters!

    If what you say is true about the extensive research, then why aren't METAL ferrules supplied with the parallel stranded cable housing rather than the plastic ferrules?!?

    Why isn't the plastic, outer sheath made with a more UV/etc. resistant material?

    'I' would suspect that the parallel stranded cable housing is more of a bean-counter's choice raher than a choice made by EITHER Shimano's OR Campagnolo's engineering teams.

    While I am reluctant to choose parallel stranded cable housing, I am not totally adverse to using it. I certainly have parallel stranded housing on a few of my bikes because it was handier at the particular moment in time (i.e., since it comes with the brake cable "kits" which Campagnolo & Shimano provide, it's a matter of might-as-well-use it situation); but, if I am not using a "kit" of replacement cables & housing then I prefer to cut the replacement housing for the derailleur cables from brake cable housing.

    For the moment, I guess that MY preference has to be chalked up to a philosophical difference where 'I' would prefer to use something which is not prone to what I perceive to have an obvious, in-built, potential failure (no matter how remote) if 'I' am negligent in the particular component's maintenance ...

    OT. One could say that for similar reasons, no matter how great a rubber "timing"/(DRIVE) belt may be AND no matter how long it may theoretically last when used on a bicycle, its limitations exceed its realistic utility unless one wants to harken back to the 50s-and-before when single speed, coaster brake bikes were the norm and THE particular chainwheel & cog configuration was probably going to be IT for the life of the bike (yes, of course, the cog & chainwheel can be replaced on a belt driven bike, but what a nuisance it must be by comparison where you have to hope the shop can order the part-or-parts) OR unless one chooses to be saddled with using an internally geared hub.

    External Cogs & derailleurs are wonderful things, IMO.

    Despite my belief that the limitations of the parallel stranded cable housing exceed their utility without offering superior performance, I am happy for those who are inclined to only use parallel stranded cable housing for their derailleur cables because I long ago realized that we, Americans, are what I refer to as "a pet rock nation" for whom what is sold must be bought ...

    And so, as a Philistine (yes, that means you can pray that I will someday see-the-light and that I will then better appreciate the gifts that Shimano & Campagnolo engineers have given us as those gifts have have been given to us without question), I will continue to say "why put up with the nuisance" of even having to go back and make any future adjustments if one doesn't have to when EITHER coiled brake cable housing OR segmented Nokon-or-Aztec housing will work as well, or better?

    BTW. While you make think otherwise, I'm all about ease-of-use while riding (i.e., consistently clean shifts) & ease-of-use when performing maintenance ...
     
  10. oldbobcat

    oldbobcat Well-Known Member

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    This is getting way off topic. The gist of my advice is, Ultegra 6800 is not a good laboratory for home mechanics with little experience in front derailleur adjustment to cut their teeth on. And if the service department of the shop that sold you the bike doesn't inspire a whole lot of confidence, find one that does. And if you want to learn your chops in derailleur adjustment, start with something simpler, like mountain bikes or Shimano 10-speed.
     
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