Internal Cable Routing: Styles, Pros & Cons...

[back40]

I've just tried bonding a titanium tube through a carbon top tube. I'm going to run continuous casing though, no stops or bare cable. Full casing may be heavier but no friction or contamination issues.

back40 bicycleworks

Glen J

[Eric Estlund]

isn't that just tubing with an ID of 5.5mm?

No- it's a stepped ferrule.

I do jet ports, flush mount, braze ons, full length, stepped etc. based on the needs of the bike. They all work.

[Brendon Potts]

Sorry to bring this post back from the dead, but I'm considering trying this out, and I've got some questions. I've found sources for stainless brake line, but it seems like brass is the more common material of choice for this, so do you all just use Nova as a supplier? Why do folks use brass instead of stainless? I guess it seems like stainless would last longer, but I'm curious if folks have other reasons. Thanks much for any and all help!

[veryredbike]

I don't think "lasting" is really an issue with brass. Either will survive as long as the bike does. My guess is folks are using brass because it's easier to bend and line up than stainless, but would be curious to find out if I'm off base there.

[Gattonero]

Sorry to bring this post back from the dead, but I'm considering trying this out, and I've got some questions. I've found sources for stainless brake line, but it seems like brass is the more common material of choice for this, so do you all just use Nova as a supplier? Why do folks use brass instead of stainless? I guess it seems like stainless would last longer, but I'm curious if folks have other reasons. Thanks much for any and all help!

The problem with brass is corrosion/oxide forming inside, good to spray some protective wax

[Alistair]

I had a chat with a respected builder a few years back who told me he had switched from brass to stainless for internal cable runs inside the top tube because he had had some early bikes of his come back with internal brass cable tunnels that had fatigue cracked and broken. He told me that none of the stainless ones have ever come back with any issues.

Not suggesting that that's a definitive or necessarily meaningful sample size of course, just passing it along, fyi.

Alistair.

[Curt Goodrich]

I had a similar discussion with I think the same builder. One of my early employers in the business only used the Nova internal kit. I installed lots of them It worked fine. When I hung out my own shingle I made the switch to stainless. I see no reason to use anything else.

[Kumo Cycles]

I anneal the brass tube to soften it before I install the cable run.

Makes it easier to give it a nice bend and should reduce the risk of any cracking down the track

[Jonathan]

I've had to repair/replace a few of the brass tubes, but every one had the hole pop up on top of the tube in the perfect location to collect sweat. Location location location; is what they say about real estate.

[Ben Hudson]

Sorry to revive an ancient thread again, but I was looking for the elusive video of H. Hirose winding wire onto a steerer tube for his internal dynamo routing method* and came across this one of him installing a brake cable in the top tube: . I learnt more in the first four minutes than in hours of reading and headscratching.



* if anyone knows where this is, do let me know. I'm pretty sure it's on this build (ランドナーの製作) but there are 110 videos in the series...

[Eric Estlund]

Just an unrelated safety tip from that video- avoid knit gloves with rotary tools such as drills. A snagged glove can result in a some pretty serious injuries. Knit gloves are great for heat and some cutting concerns, but can snag and be pulled into spinning bits, locking your hand against the tool, possibly breaking fingers, de-sheathing, etc. If you must wear gloves with rotary tools consider leather or similar.

[Ben Hudson]

Just an unrelated safety tip from that video- avoid knit gloves with rotary tools such as drills. A snagged glove can result in a some pretty serious injuries. Knit gloves are great for heat and some cutting concerns, but can snag and be pulled into spinning bits, locking your hand against the tool, possibly breaking fingers, de-sheathing, etc. If you must wear gloves with rotary tools consider leather or similar.

Oh yeah, good point. Especially with super-strong high temp resistant gloves made of Kevlar, etc. Deglove sartorially or be degloved medically.

[Eric Estlund]

If it just rips a glove off your hand, you will be phenomenally lucky.

[DanB]

Degloving is a technical medical term and refers to more than taking your gloves off. It often involves turning several layers of skin inside out. Not the kind of thing which happens to people who are phenomenally lucky.

[Eric Estlund]

"sartorially"

[Eric Estlund]

I'll also note that I've had co-workers that experienced all of these, so it's not just a theoretical danger.

[David Tollefson]

.

To get this thread off the morbid tangent... Thanks for posting this video link! Cool to see it in action. Though it seemed he was rather light on the flux (imho).

[halekai]

I had a chat with a respected builder a few years back who told me he had switched from brass to stainless for internal cable runs inside the top tube because he had had some early bikes of his come back with internal brass cable tunnels that had fatigue cracked and broken. He told me that none of the stainless ones have ever come back with any issues.

Not suggesting that that's a definitive or necessarily meaningful sample size of course, just passing it along, fyi.

Alistair.

I have not done one of these in a while but I did have one of my brass internal tubes fatigue on me. Luckily it was a TT that was sitting on the shelf for about a year. I went to braze the frame together and happened to notice the issue. (easily could have not noticed!)

I determined that it was user error and when I was fishing the tube through it must have introduced a stressed area. I would suggest when you are fishing it through the you go for a relaxed fit. Don't fight it and use a piece of housing in the brass tube while fishing to keep things rigid.

Having said all that...Ill be using stainless when I do this again.

[Gattonero]

My 2c about using a standard drilling bit for enlarging holes: not a good idea. The two cutting faces of a drill bit will inevitably get the hole to veer off one side, there is a reason why a three-sided bit is used for this purpose.

Also, for the rear brake is preferable to have the cable coming from the bottom of the tube a the front (by the bars), and leaving at the top by the rear (by the brake) side. If you look at that video between 3:25-3:30 you see the routing makes that cable to form a U-bend that ven if shallow and gentle, is still not as good as the cable going almost in a straight line.

[false_aesthetic]

The two cutting faces of a drill bit will inevitably get the hole to veer off one side, there is a reason why a three-sided bit is used for this purpose.

What is proper name for a 3-sided bit? I asked friend and he referred me to Startseite "MEGA-Spike-Drill-Uni" but there has to be a more common name for it. Right?