Tuesday, July 24, 2012

Brake Cable Guides Along the Top Tube

Testing a Selle Anatomica Titanico, New Version
I've been curious about the different styles of rear brake cable routing along top tubes. If you look at vintage roadbikes and some currently produced classic bikes, they tend to have three guides along the top, with the brake cable passing through them enclosed in housing. 

Axiom S, Clover
On the other hand, modern bikes tend to have two stop guides underneath the top tube, with the exposed inner cable stretched between them. 

Susan's Pink Sketchy
There are variations to this, such as routing the two stop guides along the side of the top tube, as well as possibly along the top. There is also internal routing and a variety of methods for bikes without top tubes, but that is a separate story. The three through-guides along the top vs the two stop-guides (usually) along the bottom seem to be the dominant methods as far as I can tell. 

Top Tube Cable Routing
From a purely tactile standpoint, my own preference is the top routing. I don't like feeling the exposed brake cable along the bottom when I pick up the bike by the top tube. And when it's routed along the side I can sometimes feel it with my leg, or my clothing catches on one of the stop guides. Some say they prefer the vintage style because the brake cable is safer from the elements when enclosed in housing. Others explain that the two stop-guides method improves rear braking and saves weight - while others still argue that the differences are not significant enough to be of real advantage. I've also heard horror stories about people's genitals getting torn on the cable guides along the top, which is supposedly why this style is no longer the norm. I have no idea how legitimate any of these reasons are. Is there is an official explanation of the advantages of one style over another? Which do you prefer?

59 comments:

  1. Internally routed cables are much neater and resolve many of the problems with carrying your bike. BTW, top mounted cables tended to corrode, as rider sweat would inevitably pull around the braze on. I'm thinking the story about getting your "bits" caught in the cable are apocryphal :-)

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  2. For ease of fitting top tube mounted bags I prefer cables to be mounted below the the top tube. I can't imagine what people might be doing to be so unfortunate to get their genitals torn on cable guides, though maybe this guy could tell us?

    http://www.telegraph.co.uk/news/uknews/1567410/Man-who-had-sex-with-bike-in-court.html

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  3. I always assumed that the cable on top method was so people could carry flat bar bikes on their shoulder without the cable digging in. Now I also want to know the 'real' reason!

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  4. Cyclocross bikes of any vintage normally have the cable above the tube to facilitate shouldering the bike. Mine has bare brake and shift cable.

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  5. Hi,
    I have a 1998 Mountain bike Trek 7000 (alu) converted to a city bike. It came with all the cables passing through the top tube. This is my preferred location as a single rider. The main reason I prefer this to "below the top tube" is that, this way, I can grab the bike on my shoulder comfortably, whenever I need to cross obstacles like steps (nowadays) or difficult terrain (previously, as a mountain biker).
    I had a few falls over the time, but never involving these cables.
    The only downside I can think of, while riding in the city, is that I can´t change gears when I transport my girlfriend on the top tube. I also risk to damage the paint by doing it. But one must have it's priority's, and the romantic feeling of riding with her there beats my biker aficionado concerns.

    I had another adapted mountain bike (that got stolen) that solved all these problems. It had a carved tunnel underneath the top tube, where the cables passed. It was a much simpler Cromoly GT Tequesta, which rode great all around. I don't see any brand using that scheme anymore.

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  6. I was wondering this too, recently. I found your blog looking for reviews of Sevens, and now I'm in the process of ordering one. I think I'm going with the side routing to make it more comfortable to carry and to lean on the top tube while stretching/ stopping -- I don't find myself kneeing it or anything on bikes I've tried. But I do like the covered cable on my old hybrid -- it feels sturdier even if it might not be. (That rear brake cable is, in fact, the only cable I've had snap while riding.)

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  7. my dear, up to the genital mutilation, i was with you and felt you express my obsession with bicycles in ways I can only dream off. for what its worth, i have an old sunbeam with those loose little spring brackets, and it's original, which works really well because it makes it ones choice where brake cables go, within reason.

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  8. I prefer cable beneath the top tube. The two bike racks I've used have had a problem with top and side cables. The side cables get caught on a Saris platform rack center holder and top cables got compressed with a Sports Rack clamp, which I had to pad between the cabling and the tube and between the cabling and the clamp. I also choose to pick up my bikes by the head tube and seat tube. I feel there is less stress on the bike where the tubes join. I also cringe when I see someone sitting on a top tube. Just my preference.

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  9. My bet is that it is cheaper to use two stop guides opposed to the three pass through guides, along with the extra cable housing, so that is why you see it more often. Probably another reason is the increased friction of running the cable through that length of housing.

    I prefer the top pass-through guides but most of my bikes do not have them. I think it is a cleaner look and it helps when I have to put my bike on my truck rack. The tie downs pinch the cable if it is not in a housing.

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  10. I think the interrupted housing, with a length of bare cable stretched between housing stops, tends to feel a bit better most of the time. More housing creates more friction and some fully-enclosed brake cable setups can be a bit mushy if everything isn't perfect. It also seems to flex a bit better at the head tube when turning. Enclosed housing slides back and forth and sometimes gets caught up and kinked.

    The other advantage of the interrupted housing is that if you need extra slack in the cable during repairs, you can pop the housing out of the cable stops and move things around a bit. This comes up quite a bit in the shop, but probably doesn't affect the typical rider much.

    Full housing has the advantage of protecting the cable a bit better from the elements (but again, once moisture and a bit of corrosion gets in there, it's a much bigger problem) and, if you're the type to have things hanging off your top tube, keeps you from pinching the cables.

    The relative merits/demerits are minor, my preference leans towards the easier maintenance of the interrupted housing, but I've had bikes with enclosed housing too, and was quite happy with them for the most part.

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  11. Since the cable housing compresses when the brake is applied, cable-stops will make the rear brake feel much less spongy, as they eliminate that long section of housing on the top tube. This also makes the rear brake feel more like the front.

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  12. Wiring for a dynamo powered taillight has been hassle. My B&M Toplight Line is mounted to the seat post binder bolt. I use three cable clamps along the top tube for running a single coax cable to said taillight. Cable clamps look better than the ubiquitous tie-wraps.

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  13. The reason for the continuous cable to the rear was simple: It made the bike easier to assemble. Especially with non-aero routing, you didn't need to cut the cable housing with precision, as the front loops over the handlebars will take up the slack.

    The weight disadvantage of this setup is real: Cable housing is surprisingly heavy. A more important point is the compression of the housing, which leads to a very mushy feel at the brake lever. I once had a Bike Friday with about 2 feet of continuous rear brake cable housing, routed in multiple turns, and as a result, the rear cantilever brake had no power at all.

    The modern setup, with two cable stops, reduces the amount of cable housing, which improves the brake feel and power. However, the stops need to be placed with foresight and precision, and the cables need to be cut just right, to get a smooth transition. Especially at the front, it often is hard to avoid a kink in the cable routing, as shown in your photo of the bike labeled "Axiom". Rene Herse and Alex Singer brazed a second loop near the front cable stop, which guided the cable housing and guaranteed a smooth transition, see

    http://www.bikequarterly.com/images/Hersefixed.jpg

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    1. Compression would have been an issue for the old non-lined casing. Modern casing, not so sure.

      Weight penalties for down market stuff. Even in the day CLB made 85 gram cable casing sets. Modern casing is very light.

      With a builder possessing the extraordinary abilities of Herse or Singer, ordinary considerations go out the window.

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    2. I've also been told that with modern housing it's not an issue and the real reason is weight and change in aesthetic.

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    3. Rene Herse and Alex Singer brazed a second loop near the front cable stop, which guided the cable housing and guaranteed a smooth transition, see

      The constructeurs weren't the only ones who did this. Many production bikes from France and England, including low-end bikes, had braze-on cable stops with the additional guiding loop an inch away.

      Modern housing, including the good stuff, does indeed compress, maybe not as much as vintage stuff, but it does. You can see it deform as you apply brake force. That deformation translates into a loss of force on the pads.

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    4. Also, internally routing the cable causes the same kinking problems that Jan mentions regarding cable stops. Take a look at any old Herse with internal cable routing. The housing is usually kinked where it enters the front of the top tube.

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    5. "The modern setup, with two cable stops, reduces the amount of cable housing, which improves the brake feel and power. However, the stops need to be placed with foresight and precision ...Especially at the front, it often is hard to avoid a kink in the cable routing, as shown in your photo of the bike labeled "Axiom". "

      Kink or not, that bike had the best braking power and modulation of any I've tried!

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    6. Matthew -- Modern brake cable housing compresses, that's why indexed shifting can't use brake cable housing.

      (And you can't used shift cable housing for braking because the uncompressible housing won't handle braking forces, so I think *some* compression is a feature.)

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  14. I always figured mfgs went to side cable mounting after changing the brake lever* cable routing as going from the middle of the handle bar to the side of the top tube looked better. With traditional levers, running full casing on the top looks good and works fine.

    The weight argument seems a paper tiger. Cable casing is not all that heavy. And recently read a post by Tyler of Firefly which said he runs full casing through the inside of his frames when he does in tube routing.

    Likewise the genital tearing argument seems more tall tale than true. Most accidents throw the rider off the bike, not up the top tube.

    *(An aside: I hate using the term, 'aero lever.' The name is one of those marketing pearls that fuels conventional wisdom. Not aware of any study proving running cable under bar tape makes a bike more aerodynamic.)

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  15. I'm not sure the "sore genital" issue is a reason for bottom-mounting the cables at all as most of the mountain bikes and cross bikes that I have seen have top=of-the-top-tube cable mounting. One is MUCH more likely to fall of one of those than a regular road bike!

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  16. Left side mount cable stops with split housings for better braking.
    I had full housing on my Bianchi Cross Bike and thanks to Steve Marcus, Bianchi Rep., had them plucked off and re-done by Bianchi with a warranty paint job. It improved the rear brake stopping power greatly.
    Top tube right braze on cable stop with braze on pulley with bare cable down the seatstay for Sturmey Archer.

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  17. I use three cable clamps to run a coax cable along the top tube to a dynamo powered taillight. (Taillight is mounted to the seat post binder bolt). This setup looks better than the ubiquitous tie-wrap and works just as well.

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  18. I have had two wrecks on bikes with the cable guides on the top of the top tube. The first I was thrown sideways from the bike. The second was a head on collision with a jeep driving on the sidewalk after I came around a corner. The damage done came from smashing into the area where the stem and fork connect. The cable guides were unharmed.

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  19. The main advantage of having cable stops at either end of the top tube (regardless if they're on top or below) is that you have less brake cable housing compression, so a more direct modulation between lever and brake. If the housing and ferrules are of high quality, there shouldn't be issues of exposure to the elements.

    The disadvantage to this method is that the exposed cable often scratches the paint along the top tube.

    Personally, I prefer routing above the top tube, because routing below makes it harder to carry the bike-- the cable digs into my palm. And routing to the side causes rubbing against my leg (my leg often contacts the top tube).

    The guides on your Mercian are more consistent with 1980s road bikes, and I tend to like these the most. Earlier than that, most bikes used clamps. And starting around the early 90s, the stops on either end with exposed cable runs became the dominant style.

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    1. +1 on less housing compression with the exposed cable setup. I've found this to significantly improve the crispness of the rear brakes.

      The only downside I've found to routing on the top is for the occasional moment when you want to sit lightly on your top tube at a stop - uncomfortable. Internal routing has all the obvious advantages, though I dislike the look and it seems a shame to pierce the tubes from an engineering perspective. My first choice would be outside routing at the 5:00 or 7:00 O'clock position - doesn't hit your leg while riding, doesn't hit your hand while carrying.

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    2. I like how Hiroshi sets up the rear brake cabling on his Ebisus:

      http://www.flickr.com/photos/flickr_lee/4037944856/

      The feel and performance are both crisp with this setup (Cane Creek SCR-5C levers with older Shimano cantilever brakes).

      -Lee

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    3. Lee - Interesting. I am checking my pictures and I think the Rawland rSogn might have the same setup, but along the side.

      somervillain -BTW, Mercian gives you a choice of the modern vs vintage style routing.

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  20. I prefer three clip on stainless across the top tube. Braze on cable guides will eventually rust or even brake or get bent resulting in costly repair. The clip ons are easily removed for replacement or cleaning.

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  21. Interesting, I just finished rebuilding a 1974 Miyata (which I would consider vintage) that has the rear brake cable mounted at the bottom position of the tube. The stops for the housing did not have the cuts that are often there which allow you to slide the cable into the stop.

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  22. Using less housing doesn't so much save weight as improve rear brake response slightly. The housing compresses slightly when you actuate the brake; the top tube (when you use the two cable stops rather than the guides) does not. Unless you're a gorilla, of course.

    It's a moot point for me, as I ride fixed right now, but when I do use a rear brake, I prefer cable stops under the top tube, simply because they look nicer to me. Even a weakrear brake can generally still lock up the wheel, so the efficiency gain isn't really all that important in real life.

    Though actually I much prefer clamp-on cable guides; you can take them off if you're running fixed, and you can put them on if you're not, and you can sometimes find nice ornate vintage ones that are pleasing to look upon. Either way you'll stop just fine. It's the front brake that does most of the work anyway, except perhaps on a loaded longtail.

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  23. Re "less housing compression" - I should have included that! But as others have said, is there really much of a difference in braking power?

    And are there any other real benefits to having the cable enclosed, than not scratching the paint on the TT?..

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    1. The difference in braking power is real. Jan Heine mentioned his Bike Friday with two feet of continuous housing run. My tandem, which has well over 5 feet of brake cable going ot the rear, only has short segments of housing where the three frame segments attach, and I can't feel any difference in brake feel between the front and rear brakes. I also use the pricey Jagwire "L3" housing on all my bikes. I still feel the difference with long housing runs.

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    2. I think that tandems and other bikes that require an unusually long stretch of cable are a separate category, but that's interesting to know.

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    3. I've found the most difference using cantilever brakes. I have encountered bikes with fully enclosed routing for rear cantiis that were impossible to get good braking force out of (this has to do with design considerations in addition to the cable routing, of course) which were mostly solved by swapping the cantis out for v-brakes

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  24. Btw, I"ve seen paint rubbed off the top tube from enclosed housing since the cable guides are not clamps it's quite easy for the housing to move about.

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    1. Ditto. Almost all of the vintage roadbikes I've owned have had paint rubbed off in that area.

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    2. Also, many, many road bikes had split cable housing in the 70's and 80's. I know because I spent years assembling and repairing them :) So I wouldn't necessarily say modern bikes are done one way and 'vintage' bikes done another...

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    3. Yep, housing does cause scuffing along the top tube, all my bikes have it. But, exposed cable scratches too, mostly from when you carry the bike. Sometimes the bike maker includes a clear or black sleeve for the cable run between the stops, but 1) I think the sleeves look bad, and 2) they don't prevent scratching. Paint will eventually get scratched regardless of the routing method (except internally routed).

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    4. Anon 11:52 - Interesting, can you name some? I don't think I've ever seen that in a pre-90s bike.

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    5. Of course....One can look at this.

      http://sheldonbrown.com/schwinn-braze.html

      Besides Schwinn, I seem to recall Motobecanes, Miyata, Nishiki,
      Raleigh, etc....My mind is weak :) But it seems there were more bikes with split cables than without.

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    6. V, I suspect by now you've found photos of several older, classic, bikes with the split housing on the internet. Anyway, a walk down memory lane got me searching and there were too many to include but I had forgotten how sweet some of these were. Somervillain mentioned the old Raleighs and I remember a lot of Schwinns and Justine reminded me of Peugeots, too. Sorry, not adding anything of substance here, just another lovely photo...:)
      http://www.classicrendezvous.com/USA/Schwinn/Superior_1980s.htm

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    7. V,
      If you look at Dawes from the 70's you'll find some with side split cable routing.

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  25. Anon 11:52 is right, many 70s road bikes did have split housing, but still the vast majority of bikes had continuous housing runs with clamps. You can see the early split housings on 1970s Raleigh Super Courses, for example. These have the nice extra "guiding" loop that I mentioned earlier.

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    1. Was the split housing ever done as early as the late 1940s? If you remember my post about the 1940s Mercian, here is a closeup of the rear brake cable routing on that bike. In the comments someone asked whether the braze-ons were done aftermarket, when the bike was getting restored, and I had wondered the same thing.

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    2. "Was the split housing ever done as early as the late 1940s?" - A quick research among the bikes submitted by readers to the gallery on http://www.classiclightweights.co.uk/readers_bikes.html shows that the use of cable stops on the right side of the top tube of British Lightweights seems to have started in 1947 - I did not check all the entries, but it seems that none of the pre-war bikes has cable stops, while quite a number of early post-war bikes (1947 - 1949) is fitted with them. And although it is not stated clearly in some of the entries if the frames are in original condition or have been altered in their later life, I guess there is strong evidence that the use use of split housing on British lightweights was taken up soon after WW II.

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  26. I've ridden with just about every cable setup imaginable. I still prefer fully-enclosed cable housings along the top tube. For one thing, I like the look. But, more important (Yes, really!), they leave the cable less prone to the elements, and are simpler to set up and maintain. Also, I feel that with modern cables and housings, there really isn't much, if any, difference in smoothness of operation between fully-enclosed and double-stop brake cables.

    I've had three bikes with cables that ran fully-housed inside the top tube. I have never liked that setup because it's more difficult to set up and replace cables in them. And, I don't like the idea of such a large opening in a frame tube (especially if the tube is steel) because it allows dirt and water to enter.

    If I may, I'll provide a partial answer to your question to 11:52. Many Schwinns of the '70's and '80's--and even the '60's--had double-stop brake cables. I know because I had one and worked on many of them. Also, I can recall seeing various Japanese (Panasonic, Miyata, Nishiki) and European (Peugeot, Motobecane, Raleigh) bikes of that era with that setup. I'm sure there were others; I'm just recollecting the ones I've owned, ridden or worked on.

    On the other hand, fully-enclosed cables indeed became less common about 20 years ago or thereabouts. That's when frames made from materials other than steel entered the mass market. As cable "tunnels" can't be brazed on to carbon fiber, and it's difficult to braze or weld them onto titanium or aluminum, manufacturers went to the double-stop system because it was easier for them. For one thing, they only had to attach two stops instead of three tunnels. But, even more to the point, tunnels are more delicate than stops and require more finishing work after they're brazed.

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  27. Hm. For someone so concerned with aesthetics well...it doesn't surprise me you'd throw them aside when preferring top cable routing.

    As for who/what/why my only preference is not top. Braking performance is somewhat influenced by routing.

    Genitals, fear, whatever. So you have a reason for disliking every single routing option. Wow.

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  28. internally routed hydraulic or electronic is the future.

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    1. The future of expensive, complex, nightmarish repairs yes. ;)

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    2. bleeding a hydraulic line is no more difficult than pushing on a syringe or squeezing a bottle.

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  29. The cost of the ~30cm of cable housing the big makers save really does start to add up over a production run of thousands of bikes, as well as the number of braze-ons.

    Someone has to cut the cables to length anyway so it's not as much work to cut extra cables as it would be to braze 3 small flimsy braze-ons instead of 2 bigger modern stops.

    Like many "advances" in cycling, this one is done to make bicycles more profitable and marketing reasons are what we're all sold on, like increased braking power or stronger steerers or whatever the next big thing is.

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  30. If anyone knows whether or not genitals should influence one's choice of cable routing, I am that person. And I am here to state unequivocally that plumbing should have absolutely no effect on wiring.

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    1. This made me smile...Thank you. Your insights and experience are appreciated!

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  31. With regard to your question, my preferences are for less housing. I used to think that fully enclosed cables were cool....Went through the old metal clamps, and then the brazed-on guides on various bikes. Both ended up being a hassle and in my old age I lean towards less is more. I think under the top tube is better.

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  32. I have many pairs of jeans that over the years have been caught on top-tube routed cable routing. May not be genitals, but damn close. I've also had sweaters and shirts caught on cable clamps when portaging.

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  33. Internal cable in top tube. Or fixed gear.
    Or coaster brake???

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  34. Personally, I like fully enclosed cables for a bike that's going to see a lot of mud, crud, and bad weather. Yes, it's handy to be able to un-hook the cables from the cable stops to get more slack, but even with relatively wide tires, I can generally get the brake open enough with the brake release and/or barrel adjuster (if necessary) to get the wheel out.
    Not all housing is the same, and if you don't like the mushy feeling, use better housing.
    But that said, all of this still only applies to the rear brake. And it's not that hard to lock up the rear wheel. To my mind, adequate brake performance means being able to lock up the wheel, and squeezing harder after that doesn't slow you down any more. If the rear caliper doesn't squeeze as hard as the front, that's okay because it's easier to lock up the rear wheel than the front (because the weight comes off it as you decelerate). And you can definitely get housing that's good enough for that.
    I have two '70's Raleighs, which both have fully housed cables running along the top of the top tube with clamps. I put them on top to make it easier to carry the bike, and because the clamps look nicer that way. The one I use for long distances has blue anodized Nokon segmented housing (used two packages' worth to have enough... no, I swear I'm not a slave to fashion!) and it performs quite well. It's also lasted through at least five years of all-weather brevet riding. I do miss being able to sit on the top tube, though.

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