Bicycle shifter, brake cable, and housing standards - article comments

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To prevent article pages from being miles long, but preserve all the useful questions and answers provided over time, I've decided to copy/paste the website comments to the forum - and "move" further discussions here.

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Bicycle shifter, brake cable, and housing standards

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  1. Ammie
    17/01/2021 at 19:04
    You are so detailed I love it
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    17/02/2021 at 08:22
    Excellent article.
    Any idea why cable housings labelled “Shimano SIS” would be spirallly wound (like brake cable housings)?
    I was about to replace my shifter cables using the the housings with these labels, thinking that they would have to be shifter housings until I checked them a little more closely
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      17/02/2021 at 11:34
      Can I swap that question for an easier one? Higgs boson, black holes, relativity theory? Because cycling industry engineering, powered by cycling industry marketing is a mystery for the 22nd century minds to resolve. 🙂
      On a more serious note:
      Here, in Serbia, Shimano sells shifter housing that is 4 mm wide (outer diameter), has the spirally-coiled steel inserts, like brake housing, and is labeled as Shimano SP40 SIS.
      They also sell what I consider the proper shifter housing, also 4 mm wide, labeled as Shimano OT-SP41 SIS.
      In my experience, SP41 works more precisely, better, in practice.
      But SP40 does work a bit better than the brake housing (I often see brake housing used for shifter cables, on the brand new low-end bicycles sold locally).
      I’ll edit the article with this info – think it’s important to note, and avoid any confusion.
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      04/04/2021 at 05:35
      not all cable housing is the same,cables labled shimano sis are much stiffer cable housing and its basically used for modern road bike shifters,some cable housing is 4mm thick and some cable housing is 5 mm thick.brake cables for a mountain bike is more flexable and 5 mm thick,all brake cables have that internal spiral pattern.when purchasing mountain bike cables its a different setup to the modern road bike cables altogether.
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    18/02/2021 at 12:02
    Thanks for the clear answer.
    How about some worked solutions to a few Navier-Stokes problems?
    Following your confirmation, just replaced all shifter cables with OT-SP41, although the bike shop made a 500% mark up. Buying in bulk from now on.
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      04/04/2021 at 05:43
      all shifter cable has long straight strands,no spiral pattern at all,and shifter cable housing are much tougher than brake cable housing and they are more thiner.
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      04/04/2021 at 05:56
      if you see a cable labled shimano sis and it has a spiral pattern it is a modern road bike brake cable,i made a little mistake in my other post.most modern road bike break cables are much firmer then mountain bike brake cables
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    07/03/2021 at 12:14
    but, seriously, don’t clean your bike and forget your nails lol
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      07/03/2021 at 12:44
      Probably the most useful piece of bicycle-mechanics related advice. If I could, I’d keep this comment pinned on top of all the other comments.
      After all: “cleanliness is next to godliness!”
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    12/05/2021 at 16:47
    The Shimano SIS-SP41 shifter cable housing has been pre-lubricated over its entire length with a special silicone lubricant. This reduces cable resistance by 10% (compared to SP40) and guarantees fast, precise shifting. It is not necessary to grease the cable when installing.
    This is from a Shimano brochure
  1. John Gallen
    17/08/2021 at 15:32
    Great article that provided me with all the info I needed regarding cable differences, and for that, thank you!
    On another note…. would a regular pliers cut either the brake or shifter cable housing or is there a special tool for this?
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    18/08/2021 at 11:32
    Thank you Relja for your response, and the links too 🙂
    Much appreciated!
    I used to be able to take apart my bikes as a teen in the 1980s, but I’m a bit out of my depth (but enjoying re-learning) when it comes to modern bikes’ disc breaks, shifters, etc.
    Thanks again, enjoying your site!
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    17/09/2021 at 04:18
    There’s one more standard for shifter cables–Brompton. Like so many parts of these wonderful but also incredibly proprietary bikes, it’s a whole different standard again. And, there’s two different kinds of those! Ugh. My own bike is sitting partly disassembled in my foyer right now.
    Anyway, pre-2017, Bromptons have a very different anchor, 3 mm thick and 5 mm long. After 2017, the thickness is still the same, but they are shorter (Brompton re-did the shifting significantly in other ways, too). A post-2017 shifter cable works fine for a pre-2017 bike, but not the other way around.
    Just in case someone happens to be Googling this topic, maybe they’ll find this comment. 🙂
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    12/01/2022 at 17:33
    Hey Relja,
    You say in your excellent article that there is no difference in brake cable housing (all 5mm). But I’m sitting next to a 5.5 mm roll of housing right now (see it being sold here:
    Any idea what the benefits of that could be, or downsides for that matter 😉
    With all components shortages I find myself grabbing every piece of equipment I can…
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      19/01/2022 at 20:21
      Hi Justin,
      Brake housing I’ve worked with so far could all be fitted with the 5 mm housing caps/ends (Shimano, SRAM, Promax etc.). Those caps have an inner diameter of a bit over 5 mm so they don’t fit very snugly, but the diameter is well under even 5.1 mm, so I don’t think they would fit 5.5 mm wide housing.
      I’ve seen some reinforced brake housing that’s made to resist compression better – thus providing a firmer, less squishy feel on the brakes, and better modulation of the braking force. But I haven’t seen any 5.5 mm wide so far.
      Do standard (Shimano) brake housing caps fit that housing? If not, do they sell wider housing ends for that housing?
      Hydraulic brake hoses can be 5.5 mm wide, but I don’t know about any brake cable housing that thick.
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    21/04/2022 at 11:33
    thats a new one for me as well,all shimano brake housing i have ever seen has been 5mm wide,the only difference i have seen is some brake cable housing is more flexable for a mountain bike and more stiffer for road bikes mtb housing and slr housing,i have tried both types of brake housing on my road bikes and either type works fine,5 mm brake cable housing is the industry standard,when i worked on an older road bike the cable housing did seem thicker although i never measured it.
  1. mike
    21/04/2022 at 11:44
    there would be no purpose in buying 5.5 mm housing today as all end caps i have seen are to fit 5mm housing as stated by Relja,there are two different sizes for gear housing but those are 4mm and under.
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    25/04/2022 at 13:36
    good braking depends on the whole braking system working properly,get one part wrong and the whole system fails,match up the levers with the calipers,run good pads,use the higher end stainless steel cables and cable housing,and learn how to adjust the brakes and clean brake surfaces,keep your wheels trued.
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    20/01/2023 at 15:50
    Does Shimano offer 5mm brake cable housing?
    If so ehat are the choices?
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      21/01/2023 at 06:40
      Yes, Shimano does make 5 mm brake cable housing.
      It’s one of the best choices in my experience – not too expensive, and good quality.
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      21/01/2023 at 07:26
      Which is better, SLR brake housing or M-system housing?
      How do they compare with Jagwire’s CGX-SL brake housing?
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    28/01/2023 at 13:41
    i have not used jagwire stuff but i have used slr and m-system brake housing from shimano,slr housing is much more responsive than m-system housing,slr housing is mainly used on road bicycles and m-systems are for mountain bike brake systems,both work very good but slr system you dont get all the flex as you do with m-system housing,i mainly use all shimano stuff as you can find their stuff just about anywhere and it works very well
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    15/05/2023 at 23:08
    “all shifter cable has long straight strands,no spiral pattern at all”
    That’s not true. Maybe it’s less common nowadays, but shifter cable can be spiral-wound too. It has one disadvantage: If the bending radius changes when pulling the lever, the spirals at the outer side spread slightly, which makes the effective cable length longer. It’s a small effect, which didn’t matter much when sprockets were further apart, but with today’s narrow gap between sprockets it can ruin the indexing. That’s why the cable with length-wise strands was introduced, where this effect is much smaller. These are called compression-less cables, which is a misnomer because neither type of cable can be compressed. Conclusion is that the spiral-wound SIS cables should be avoided, except for 8-speed or lower maybe.
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      15/05/2023 at 23:32
      Hi Joachim,
      Just to avoid any confusion:
      You (and Mike for that matter) are talking about shifter housing, not cables?
  1. Joachim
    15/05/2023 at 23:34
    “shifter housing, not cables?”
    Yes, I meant housing.
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    22/06/2023 at 00:08
    Relja, your postings are on point!!!
    Normally, my competency for cable work makes the process enjoyable, save for the time I used my only record of the closed form solution to elliptical integrals I’d just derived, written on two $100 bills, folded up to make a spacer for the rear brake rotor & piston, and forgetting to remove them before taking a test ride on a very windy day. I strongly discourage the use of graph theory & currency as a brake block no matter how perfect the idea may seem.
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    Aaron Price
    05/10/2023 at 01:43
    For shifting precision, I think the important ratio is the center-to-center distance of the cog spacing vs. the total cable pull to move the derailleur over that distance.
    (center-to-center distances below are only Shimano/SRAM compatible ones, pulled from Sheldon Brown’s classic spacing crib sheet)
    For old Shimano 1:1.7 actuation ratio:
    5/6-speed: 5.50/1.7 = 3.24 mm of cable pull to shift
    7-speed: 5.00/1.7 = 2.94 mm of cable pull to shift
    8-speed: 4.80/1.7 = 2.82 mm of cable pull to shift
    9-speed: 4.34/1.7 = 2.55 mm of cable pull to shift
    10-speed: 3.95/1.7 = 2.32 mm of cable pull to shift
    As cog spacing decreased, the amount of cable pull per shift also decreased, and the slight error or play introduced by spiral-wound cable housing became a problem for the shifting precision. However for SRAM’s standard “1:1” actuation ratio, even for 10-speed cassette spacing the amount of cable pull per shift is larger than the old 5/6-speed standard using a 1:1.7 actuation ratio:
    For SRAM 1:1.1 actuation ratio:
    7-speed: 5.00/1.1 = 4.55 mm of cable pull to shift
    8-speed: 4.80/1.1 = 4.36 mm of cable pull to shift
    9-speed: 4.34/1.1 = 3.95 mm of cable pull to shift
    10-speed: 3.95/1.1 = 3.59 mm of cable pull to shift
    In my experience with SRAM 9-speed, this very long cable pull per shift makes it possible to use the very durable and more flexible spiral-wound brake cable housing and still have crisp shifting. i.e. any play it introduces seems to be within the acceptable error margin. After all, the rear derailleur jockey pulley also has slight side-to-side float to allow the chain to center itself on the cog once the shift is accomplished. I have not tried this setup with full-length housing, only with more traditional frames where some 2/3 of the shift cable runs between cable housing stops on the frame, keeping the total housing length fairly short.
    I have also used brake housing (and spiral-wound Shimano SP40 SIS shifter housing) with Shimano setups using 1:1.7 actuation, but in that case the shifting quality is definitely degraded. For the setups I have built, it usually works acceptably up to 8-speed cog spacing, but success is partly dependent on the exact setup (i.e. how closely does the jockey pulley follow the cassette profile as it shifts).
    My guess is that this progressive degradation in shifting quality with reduced cog spacing is a significant part of the reason that Shimano changed the actuation ratios of their shift mechanisms in the most recent iterations. It is a good solution to the root problem, and I find it funny that in the most extreme case they have arrived at essentially the same actuation ratio as the SRAM “1:1” design.
    • d693f26dcd2fedd28dfc1ad7a66e01a2.jpg

      05/10/2023 at 17:34
      Hi Aaron,
      Very nicely explained and I completely agree.
      Yes, it is ironic how it took Shimano “only” a decade or so to reach the same “conclusion” that SRAM did. 🙂
      Relja Novovic
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