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  1. #1
    :p Harun's Avatar
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    cable housing: segmented/non-segmented

    I'm kind of curious why some bikes have different cable housing setups than others. Like on my newer road bike, the housing for the rear brake cable is segmented into two parts and goes from my lever to the front part of my top tube, goes bare, and then has another piece of housing from the end of the top tube and into the rear brake. On an older touring bike I have the cable housing for the brake is all enclosed. And I've seen other fancy schmancy bikes with internal routing.

    So what's the fuss with all these different types of routing methods? Does any particular method provide any advantages or disadvantages? I'd imagine that fully enclosed housing provides the best protection along with internal routing.

    I guess the reason why I'm asking these questions is because on my new road bike I'd like to just install fully enclosed housing for my brakes since they offer much better protection than having segmented housing with bare cable showing. If there are really no performance disadvantages to this other than cosmetic and the tiny additional weight of the housing I'd just like to have the best protection. I know on my bike I can't really do anything about the shift cable housing, but I'd like to do something about my brake cable housing.

    What do y'all think?

  2. #2
    rebmeM roineS JanMM's Avatar
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    More housing = more friction and more weight and more expense but better protection of the cable.
    Whether or not the friction is significant is up for debate, as is the weight.
    Housing guides and/or stops can be an issue.
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  3. #3
    cab horn
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    Quote Originally Posted by Harun View Post
    I'm kind of curious why some bikes have different cable housing setups than others. Like on my newer road bike, the housing for the rear brake cable is segmented into two parts and goes from my lever to the front part of my top tube, goes bare, and then has another piece of housing from the end of the top tube and into the rear brake. On an older touring bike I have the cable housing for the brake is all enclosed. And I've seen other fancy schmancy bikes with internal routing.

    So what's the fuss with all these different types of routing methods? Does any particular method provide any advantages or disadvantages? I'd imagine that fully enclosed housing provides the best protection along with internal routing.

    I guess the reason why I'm asking these questions is because on my new road bike I'd like to just install fully enclosed housing for my brakes since they offer much better protection than having segmented housing with bare cable showing. If there are really no performance disadvantages to this other than cosmetic and the tiny additional weight of the housing I'd just like to have the best protection. I know on my bike I can't really do anything about the shift cable housing, but I'd like to do something about my brake cable housing.

    What do y'all think?
    Do you also like ****ty feeling brakes with full length cable and housing? WTF are you doing that regular sectioned brake housing fails so catastrophically that you want to run full length?
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  4. #4
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    Cable housing has friction and generally speaking will flex, especially the spiral wound brake cables. Less housing equals less squish in the system.

    (Note: don't use the compression-less shifter housing because they don't handle lots of pressure - they simply blow out if you use them for brake housing.)

    Exception is for the solid housing, i.e. Nokon etc. The links are solid metal or similar. Pivots for each link. No compression possible. However you still have friction.

    Internal routed cables usually have a tube (metal), i.e. doesn't compress. Cheap bikes (the older Treks come to mind) required you to run the normal housing into the frame and back out the other end. Lots of flex.

    If you get the Nokons, you can use a full length teflon sheath on the cable (tip to anchor bolt). The housing segments fit over that. I have a set up like that for my derailleur cables. I used White Lightning on the cable, haven't taken it apart since I built it (fall 2007), works fine, rode in the rain more than a few times.

    cdr

  5. #5
    Great State of Varmint Panthers007's Avatar
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    Teflon, or polypropylene at least, internal-liners within the housing, has been fool-proof and lasted a long time in my, and friends, experience. A good liner will solve a plethora of problems. Match that with "Teflon-coated, multi-strand, round-wound stainless-steel cable" and you'll be set for a long time.

    But do check it periodically.
    How do you keep an idiot in suspense?

  6. #6
    Senior Member Retro Grouch's Avatar
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    This is why I don't sell bikes anymore. After going through every tiny detail, the purchase decision hangs on whether the rear brake cable has 1 length of cable housing or cable stops on the top tube.

  7. #7
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    Quote Originally Posted by carpediemracing View Post
    Internal routed cables usually have a tube (metal), i.e. doesn't compress. Cheap bikes (the older Treks come to mind) required you to run the normal housing into the frame and back out the other end. Lots of flex.
    My Look KG386 frame requires full length cable housing for the rear brake. I remember a recent discussion about someone's Pinarello frame requiring the same. I don't think it's a cheap bike thing. I've also never noticed much difference in braking from a segmented cable bike though that might have to do with me barely using the rear brake.

    There are a few other options for sealing the cable on segmented frames besides Nokon. I've been using Jagwire sealed ferrules whenever I recable one of my bikes. Jagwire also makes a cable sealing kit which might give you what you are looking for:

    http://www.speedgoat.com/product.asp...t=27&brand=124
    Last edited by joejack951; 09-07-09 at 12:06 PM.

  8. #8
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    Quote Originally Posted by joejack951 View Post
    My Look KG386 frame requires full length cable housing for the rear brake. I remember a recent discussion about someone's Pinarello frame requiring the same. I don't think it's a cheap bike thing. I've also never noticed much difference in braking from a segmented cable bike though that might have to do with me barely using the rear brake.

    There are a few other options for sealing the cable on segmented frames besides Nokon. I've been using Jagwire sealed ferrules whenever I recable one of my bikes. Jagwire also makes a cable sealing kit which might give you what you are looking for:

    http://www.speedgoat.com/product.asp...t=27&brand=124
    I should say cheap construction, not cheap bikes. The KG386 uses the same kind of through-tube housing things that the least expensive "aero" road bikes used in the mid-90s.

    Pinarellos, at least the ones I've sold a while ago, had some brass tube or something for the cable. The housing stopped an inch or two into the frame. One bike, I can't remember which, but it wasn't anything custom, had a roller mounted inside the frame, so the cable would come down inside the downtube and go out the chainstay.

    I always had a negative feeling for full housing internal setups. Punching holes in a tube (or molding them or whatever) is not very good - water/stuff can get in, typically won't come out, the housing can rattle in the frame, and it's not brain-free to replace the housing. A properly lined internal cable route job works basically like a "segmented" housing but has a flex-free, protected environment.

    I like the comment by RetroGrouch too. As he knows, the problem is that the differentiations get miniscule between bikes/frames/whatever and it comes down to minor details. It's a pain dealing with that. Although I love bikes and helping people with related things (tactics, riding, fit, etc), I don't want to get back in the retail end of things.

    I used Nokons as an example but I added "etc" because there are others and I didn't know the various other choices at that moment. There was even a ceramic one presented here in BF a while ago.

    History of brake cable housing trends:

    Full

    In 1980 or so, full length housing was the rage. The reason is that you used clamps to hold the housing in place. The thought at the time was that braze-ons compromise the tube's strength (heating steel is generally not good), so if you could avoid braze-ons, it was better. You clamped on your brake housing, rear der stop (sometimes they brazed that), front der, shifters, even bottle cages and pump pegs.

    Segmented

    Then, about 4-5 years later, braze-ons were good. We were told that everyone said braze-ons were bad a few years prior because it costs more to braze on a bunch of cable stops and manufacturers just told us that they were bad because they didn't want to pay people to braze on 3-9 extra things (2 top tube stops, rear der stop, front der mount, 2 bottle mounts, pump peg). But now brazing is okay because they are charging more. In return the bikes are lighter, more responsive feeling. Usually the cable housing stops were brazed at the thick end of the tubes, sometimes right next to the lug (or eventually even built into it).

    Full

    Then came aluminum, like Cannondale. It was cheaper to use full length housing and plastic housing holders, and it was easier than trying to weld stops onto the tubes. They were having enough trouble keeping the tubes straight during heat treating, and welding more stops would put them over the top. They riveted the rear der stop and later welded the other housing stops. Downtube shifter mounts were screwed in and the pump peg was a plastic screw. Ultimately they ended up segmented.

    Segmented

    Then came carbon. With carbon you're not molding the stops into the frame (typically - I don't know of any off hand). Instead you bond them on. This means that if you put the brakes on really hard the housing stops would pop off. In fact, one nearby shop said that this happens regularly with a major brand bike they sell (2008).

    Full

    After a lot of popped off housing stops, some folks started selling full housing carbon bikes (routed through the top tube), skipping the need to figure out how to bond something in a structurally inefficient way to a super thin carbon tube. I think one or two companies never stopped selling such full housing frames. The full housing bikes were called "aero", and were, like the original steel bikes mentioned, cheaper to make than anything requiring structural stops. Derailleur stops don't deal with the same pressure so those could still be bonded on.

    Misc notes:

    With Ti it's not really an issue because welding a stop is okay and is doable by virtually any Ti frame manufacturer.

    cdr

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