Originally Posted by joejack951
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:
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:
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.
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).
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.
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).
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.
With Ti it's not really an issue because welding a stop is okay and is doable by virtually any Ti frame manufacturer.