What's typically used as the channel for internal cable routing?

thanks, Brian

1/4" thinwall stainless welded tubing from McMaster-Carr works fine. McMaster part number 8989K19
You can get the seamless stuff for a little more, don't really see the point, but that is 89895K46

Nova sells brass tubing for that purpose.https://www.cycle-frames.com/bicycle-...ING-GUIDE.html
Depends on your frame material choice.
Aircraft Spruce sells soft aluminum fuel line which would also work for other frame materials.

You can use the somewhat stainless stuff in automobile Hydraulic lines too.

Though I only used it for an external cable guide around the seat tube
to a centerpull cantilever brake hanger bridge..

the McMaster part numbers I gave are for hydraulic tubing, that's why they are so cheap. Just over $1 a foot. I thought about ordering the 50' roll, maybe next time. You might be able to get it from a local industrial supply or hydraulics shop, I haven't tried. McMaster shipping is very reasonable.

I don't think I would bother with brass unless you are already ordering from Nova.

If you get .25", make sure it's thin enough or you'll never get the housing through it.

Just go with this route and never look back.
https://www.cycle-frames.com/bicycle-...RULE-ENDS.html

What is the standard for cable stops when running an internal brake cable in the top tube?

I don't know if there is a standard way to do it at all, although if there is, it's that part shown in Henry III's post above.

Are stops generally even used as a standard? I seem to remember the original style being to just run the whole cable through two holes in the top tube and not even bother with the guide tube.

That is how my Miyata is. I am guessing looking from the Henery post that with a ferrule and tube it is only the cable, not cable and housing, being internal.

If I had to guess, I think most people run a tube and have full-length housing. Having housing go loose through the top tube without a guide tube has been demonstrated to be a good way to get a failed top tube. Not many people doing it that way, if any.

the part linked above is two stops and the cable runs through a brass tube. Not sure that is superior in any way to full length housing. For the longest time, high-end bikes used full length housing, it really works pretty well. I'm not sure when the move to stops came about.

It still works pretty good. I don't know why anyone would do it differently. This is how I do it. full length stainless 1/4" line, very slight bend, housing stays put when installed.

I was more interested in the necessity of a cable stops for the rear brake. What is the thought on that?
Can't you just swage the end of the tubing and press a "bullet" stop in there?
Totally ghetto solution: if you have access to brass tubing that's just a hair wider than your cable you can quickly make cable stops from schrader valve stems.
Bore out the internal threads that the valve screws into and that makes a pefectly sized stop. The other end already has a cable sized hole in it.
Grind all the rubber off and solder the valve stem into the brass tubing.
You will just need to grind down the external threads to get a slide fit.

I was originally going to go with using the setup that requires you to run the housing internally also but Doug wouldn't allow me and said it was junk and pointless. He showed me the brass tubing and the steel ferrules setup. I guess why would you run the brass tubing and run the housing also? Just to make it easier to feed the cabling through? Why not just leave it and use these covers instead?

My Paramount Series PDG used these and feeding the housing through wasn't a hassle without having any internal routing tubing.

The ones from Nova have a drilled out section on one end that the tubing slips into. Then on the other end is drilled out for the diameter of the housing. It tapers down to just the diameter of the cable so no drilling is needed. Then braze the ferrules into the top tube and file down to your likings. Preferably to leave some material instead of having it sit flush otherwise there's a chance it could crack.

I actually bought the ones from Nova from Herbie as he uses these on his frames and had a few spare sets. He showed me his TT bike he made for himself and did it flush and said if he did it again he wouldn't.

Sorry, I didn't find your post very clear... I thought the main reason to run the tubing regardless of choice as to cable stops or fully housed cable was to seal the top tube from water entry.
Defintely makes running the cable, housed or not very easy with such a direct route.

Water entry was never mentioned in the entire thread or to make the top tube sealed. How does having a loose piece of housing make the tube more likely to fail? As long as the hole that you drilled out has some sort of support be it the cover plate or the piece of tubing? I don't want to start a heated argument over something so simple.

I just think with all that extra housing the caliper might feel a little mushy. Why don't builders now run full housing to the rear caliper but incorporate stops now? It gives a cleaner look, provides a solid base for the housing to stop and a small amount of housing that is going flex/compress and loose braking power. Yes now they have compressionless housing to rule those issues out but still.

people used to run cable through the top tube with no reinforcement all the time. I'm sure there are plenty of bikes like this still out there, but it's going to cause failure on some bikes so I wouldn't do it. Go ask in C&V, I have seen some horror stories posted in there.

The brass piece that Nova sells is just an alternative housing, it's not the same as two cable stops with a free run of cable between them. I don't think anyone is saying it's worse, I'm not sure it's better.

Have you quantified this mushiness ? Mushiness seems to be related to when there are curves for the cable housing. When there is a straight run, which is what one replaces in this situation, this will be insignificant or nonexistant. The cable_stop::ferrule junction isn't perfect either for introducing slop into the system.

Weight savings in the housing elimination may be one argument for this, but for me I prefer much being able to grab the top tube wherever and also the corrosion issues that are avoided. Cheap housing weighs ~15g/foot, but there are also weight additions with ferrules/brazeons for those.

Does anyone have a good tube to use for Aluminum?

Aluminum seems like the best bet.
https://www.aircraftspruce.com/catalo...mtube_5052.php