How do you do that?
One of the options I offer on my bikes is internal brake cable routing and for many the way this is done is hard to picture so I figured I’d do a bit of show and tell. There is no performance advantage to internal braking and it’s done just for the clean look.
This series of photos will give a rough idea of how this works. Most of the photos were taken with the frame upside down in the vice because I place the internals on the bottom side and it’s easiest to work with the bike upside down – either that or I get down on the floor on my back and I’m not a huge fan of that.
The first photo shows the brass tube and the stainless end barrel it is about to be brazed to. I use a 3 piece system that allows for just the cable to pass through the small brass tube. The brass tube is very low friction making the braking feel and modulation very good and solid. I do not like the internal systems that are larger and use brake cable housing through the entire length. These can make the braking pretty mushy with that much cable housing to compress every time you squeeze the lever. I also like that the 3 piece system is a good bit lighter overall.
Next you’ll see 3 holes have been drilled into the top tube. These holes will be merged into one long oval hole to accept the internal barrel with a hand file. You can then see the barrel being test fit into the hole. There is an identical hole being made at the rear end of the top tube also for the internal to exit.
With one barrel brazed to the small brass tube I then test fit the system into the top tube and I just slide the rear barrel into place to be sure all is right. I then mark and cut the brass tube to the proper finished length and end up with a brass tube with a barrel brazed to each end.
Now it’s a matter of feeding the assembly into the top tube for a final test fit before brazing it in place. You can then see the white sticky flux lathered all over the part making it ready to silver braze.
Once brazed it is allowed to cool naturally to room temperature and then it is soaked in very hot water to remove the flux. With the flux removed you can now see the silver brazing work. Next I go into the finishing aspect of the process and it involves mostly emery cloth. I use a Dynafile (hand held belt sander) to put the small scallop in the end to give it a tapered and finished appearance.
The final photos show the bike in it’s natural orientation with the internals pointing down slightly. This helps keep moisture from entering the internal tube and gives a nice natural curve to the brake cable housing as it enters and exits the internal. One very nice thing about this system is that with the stainless barrels and brass tube there is no risk of corrosion and they seal the tube so nothing can enter. It’s a fully sealed system.
One of the fun things about this process is that it can all be done by hand very quickly and efficiently. It takes me about 25 minutes of hands-on work to do the whole thing and much to many people’s surprise there is no measuring done at all. It’s all done by hand and by eye and without using digital equipment or lasers. I have nothing against that stuff but if you don’t need to use it it’s best to leave them idle.
That’s it for now. Happy braking.
Dave
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Beautiful work, Dave. Are these considered a jet vent style?
Thanks for sharing the process.
I’ve heard the term ‘jet vent’ before and I’ve never been 100% sure of what that means. Could be. Let’s you and me decide that those are indeed ‘jet vents’ and then stick with our story.
Yes those are jet vents……. at least I think they are.
dave
The one advantage I see with internal cable routing is it makes the bike easier to clean. I have a long history with steel bikes, and it seems my sweat first and mostly collects on the top tube. Rust has always been a problem for me there and it’s because I neglect to clean the bike after a sweaty ride. You live and learn.
I remember the “old” days with brake housing tunnels on the top tube. Since it was so hard to clean under there, my frames would always exhibit that line of rust directly under the housing. Then came split cable stops. First, I considered them a cheap alternative to the housing tunnels. Then I realized the benefit of easily slipping a wet rag under the wire for a quick wipe. You just have to remember to clean the cable stops themselves because they’re the second most common spot for rust to form. I keep a small, 6″ square terrycloth scrap near my bike. After a sweaty ride, I wet the rag and give the tubes a quick once-over.
So with internal housing I see it as an effort-free task to wipe the top tube and keep the bike looking new for years. I’m far from fastidious with my bike maintenance, but here I think the returns are certainly worth the effort.
So yes, I think there IS an advantage to internal brake cable routing. Feel free to use it as a selling point!