Bicycle Mechanics - Threading internal cable through tube

I'm getting ready to run a rear brake cable through the top tube. It's an inexpensive SS, and I intend to simply drill two holes in the side of the TT front and rear...but then comes the part about trying to locate and fish out the end of the cable once I have it threaded though the front hole. Maybe a piece of wire first? Please advise. (This is my first post on Bike Forums, so treat me gently.)

There's a lot of bad juju that comes with drilling a frame. Are you a framebuilder? I think threading the cable is the least of your worries.

please put down the drill...
http://www.cambriabike.com/shopexd.asp?id=26829&page=JAGWIRE+ALLOY+STICK-ON+CABLE+GUIDES

Drill first ask questions later.

Lets assume that you already have a frame with internal cable routing holes because, of course, we would not condone drilling your existing frame. In that case, you would run a derailleur wire into the front hole towards the back and then after removing the seatpost and sticking a fabricated long nose pliers into the TT you would steer the wire out the back hole. Then you would clip the stop end of the derailleur wire off and run your brake housing through each hole guided by the derailleur wire.

Easier method: Measure the distance between holes with the cable housing and run it through about two inches short of that. Use a small pick, awl, or clothes hanger wire to find the end of the housing then stick it in the hole and bring it out.

:eek:
Stop. Stop. Stop.

I'll try to be gentle. Clearly you have not thought this through.
Take the time to look at a bike that actually has thru-top-tube cable routing. you will see that it's not a matter of simply drilling a couple holes in the top tube. The cable/housing enters and exits at a very shallow angle through a special piece (boss, fixture, braze-on, whatever). There is normally a "tube within a tube" here. The cable/housing isn't simply in the open frame tube. I currently have a steel framed bike with internal cable routing and this is how it is made. I used to own an aluminum framed bike with internal cable routing and it was much the same.
Doing as you suggest, well, you would have the cables entering/exiting at a 90 degree angle which would not only look like crap, it would put an extreme bend in the cable which would have a very adverse effect on your braking performance. Your inexpensive SS frame would be basically worthless at that point. I wouldn't even do this to a Wal-mart POS. Anyone looking at your DIY "project" would have to quickly turn away for laughing hysterically.

I'm getting ready to run a rear brake cable through the top tube. It's an inexpensive SS, and I intend to simply drill two holes in the side of the TT front and rear...but then comes the part about trying to locate and fish out the end of the cable once I have it threaded though the front hole. Maybe a piece of wire first? Please advise. (This is my first post on Bike Forums, so treat me gently.)

Please stop.

Run the housing full length. You can use a zip-tie or plastic housing clamp on guides to keep it in place. All you're doing with internal cable routing is creating a headache for yourself when it comes time to change it, and also another place for water to get into the frame.

Assuming you can even modify your frame properly that is.

Another question - why do you want to to do this? Are there no braze ons for a rear brake? Solution: aforementioned zip ties or take the bike to a framebuilder and for around $20 they'll put them on.

Or are you trying to get a smoother look? If that's the case, buy a nicer frame that has internal cable routing.

I will gently add my voice to the chorus here: DON'T DRILL YOUR FRAME!

If you, for some insane reason, decide to do this, there are several posts on various internal cable routing techniques.

:eek:
Stop. Stop. Stop.

I'll try to be gentle. Clearly you have not thought this through.
Take the time to look at a bike that actually has thru-top-tube cable routing. you will see that it's not a matter of simply drilling a couple holes in the top tube. The cable/housing enters and exits at a very shallow angle through a special piece (boss, fixture, braze-on, whatever). There is normally a "tube within a tube" here. The cable/housing isn't simply in the open frame tube. I currently have a steel framed bike with internal cable routing and this is how it is made. I used to own an aluminum framed bike with internal cable routing and it was much the same.
Doing as you suggest, well, you would have the cables entering/exiting at a 90 degree angle which would not only look like crap, it would put an extreme bend in the cable which would have a very adverse effect on your braking performance. Your inexpensive SS frame would be basically worthless at that point. I wouldn't even do this to a Wal-mart POS. Anyone looking at your DIY "project" would have to quickly turn away for laughing hysterically.
This is the most compelling posting. You can't just drill a couple of 90* holes and thread the housing through.

I have a '92 Trek with the rear brake cable factory run internally by Trek and, even though the holes are drilled at the proper angles and the transition guides are in place, it is a PITA to deal with.

The Italians had it figured out some time ago. There's an internal guide inside the tube on this frame, it makes running new cable and housing easier than it would be without internal routing. Mostly, I think, it adds a bit of flair to the bike:

http://i414.photobucket.com/albums/pp226/wellbiked/DSC02031.jpg

http://i414.photobucket.com/albums/pp226/wellbiked/DSC02032.jpg

As much flair as you can get with an external bb crankset and shimano pedals on a pinarello anyways.

As much flair as you can get with an external bb crankset and shimano pedals on a pinarello anyways.

:eek:

Uh, no. And thanks.:rolleyes:

no

As much flair as you can get with an external bb crankset and shimano pedals on a pinarello anyways.

Ah, so more flair than some slave to the almighty "purism" that runs what they want and doesn't give a crap what other people think? I agree.

As much flair as you can get with an external bb crankset and shimano pedals on a pinarello anyways.

http://www.youtube.com/watch?v=f8fbrUjjivw&eurl=

Thanks for all the replies. I quess I should add a little more info on my (maybe) project. I am not a frame builder, but I'm pretty experienced at metal working. The frame I am thinking about modifying (okay, butchering) is a steel Raleigh Rush Hour, several years old. This frame originally came with plastic cable guides which were stuck on the frame with double sided tape, and of course they were removed by original owner who only rode it as a fixed gear. I bought the frame from him for $20, so if I end up ruining it I'm not out too much. (I own nine other bikes.) To allow the cables to go in and out of the top tube at an angle, I had planned to make the openings oblong. I had also planned to silver solder some sort of hoods over the openings similar to the ones in the photos posted. One worry I do have is that the holes might weaken the TT, and after a little research I see that the professionals do not put the holes both on the same side of the tube as I had originally planned. (If I ever get this project finished, and if I ever buy a camera, and if I ever learn how to post photos, I'll show you all how it turns out.)

In case anyone's wondering what the pedals are in the earlier post, they're Campagnolo Chorus. As is usually the case, "operator" is the know-it-all who doesn't know what he's talking about.

The point that I think you're missing is that the "holes" aren't simply holes, "hooded" or otherwise. With the connecting tube inside the TT, "fishing" the brake cable through is not even an issue. You simply push the cable and housing in the front and it comes out the back. Nor is it an issue of exposing the inside of your TT to the elements and inviting rust to start. The interior of the TT is still basically closed to the outside. I'm not into SS or fixies, but the Rush Hour still seems like too nice of a frame to do this to. My suggestion is to just get some new cable guides and go from there.
All this begs the question, if you have experience and conviction in the project, why did you have to ask in the first place? Just curious.

well biked, I think your bike is stunning.:thumb:

well biked, I think your bike is stunning.:thumb:

Thanks.:)

Jeez people, the man wants to tweak a $20 frame. Let him have his fun.

lfw,
The "holes" are not on the same side of the tt because of the angles that would work best for the housing. The front will usually be on the lower left side quadrant and the rear on the upper left quadrant. Those locations give it the right bend for entry and exit.

I have an early nineties Paramount Series frame (made in Japan) with internal routing and no guide tube. They were lower end frames with a braze-on hood over the holes. This hasn't been a problem.

Thanks for all the replies. I quess I should add a little more info on my (maybe) project. I am not a frame builder, but I'm pretty experienced at metal working. The frame I am thinking about modifying (okay, butchering) is a steel Raleigh Rush Hour, several years old. This frame originally came with plastic cable guides which were stuck on the frame with double sided tape, and of course they were removed by original owner who only rode it as a fixed gear. I bought the frame from him for $20, so if I end up ruining it I'm not out too much. (I own nine other bikes.) To allow the cables to go in and out of the top tube at an angle, I had planned to make the openings oblong. I had also planned to silver solder some sort of hoods over the openings similar to the ones in the photos posted. One worry I do have is that the holes might weaken the TT, and after a little research I see that the professionals do not put the holes both on the same side of the tube as I had originally planned. (If I ever get this project finished, and if I ever buy a camera, and if I ever learn how to post photos, I'll show you all how it turns out.)

Well, if you insist, you may as well do it right (http://www.novacycles.com/catalog/index.php?cPath=61_137_139).

Jeez people, the man wants to tweak a $20 frame. Let him have his fun.


Several people (including me) said he shouldn't... nobody said he couldn't.



Well, if you insist, you may as well do it right (http://www.novacycles.com/catalog/index.php?cPath=61_137_139).

Awesome link BTW! Thanks.

This thing is getting wild. Remember that my original post asked about how to fish the brake cable out of the second hole in the top tube. There were a couple of very good, to the point answers. Mmmdonuts reply pretty much mirrors my attitude towards this project. And thanks JohnD Thompson for the link, but what is "the right way?" Bike builders have been running cables through frame tubes longer than there have been prefab fixtures and parts. Some one mentioned that the cable should run through an internal tube--I have thought I might do something similar using (horrors of horrors) cheap copper tubing. This is an inexpensive bike frame, not a space rocket or an atomic sub. Some one mentioned that the reason the holes were on opposite sides of the tube was to help with the cable run. not for stress reasons. Thanks, I was wondering about that. And Norwood, I'm sorry but I just don't understand your position. This ain't a Cinelli we're talking about.

This thing is getting wild. Remember that my original post asked about how to fish the brake cable out of the second hole in the top tube. There were a couple of very good, to the point answers. Mmmdonuts reply pretty much mirrors my attitude towards this project. And thanks JohnD Thompson for the link, but what is "the right way?" Bike builders have been running cables through frame tubes longer than there have been prefab fixtures and parts. Some one mentioned that the cable should run through an internal tube--I have thought I might do something similar using (horrors of horrors) cheap copper tubing. This is an inexpensive bike frame, not a space rocket or an atomic sub. Some one mentioned that the reason the holes were on opposite sides of the tube was to help with the cable run. not for stress reasons. Thanks, I was wondering about that. And Norwood, I'm sorry but I just don't understand your position. This ain't a Cinelli we're talking about.

I agree, it's getting a little wild. As for my position, reread you first post and honestly say that it didn't sound like you had no clue. Your subsequent post show more understanding. Too bad you couldn't have expressed that in the OP. That's why it's important to give as much info in the OP as possible. As I also said, with you experience and understanding, why would getting a cable fished through a TT be a stumbling block for you?
Drill away:thumb:

My Trek has no internal tube connecting the entry and exit holes so fishing a replacement cable through the first time was very frustrating. The top tube is open at the set tube end so I could get a finger in there to guide the cable but it was still a pain. Afterward I used the old cable to guide the new housing and then replaced the inner cable.

The Trek is Al so internal rusting from water getting in through the top tube holes isn't an issue.

To the OP; if your first posting had indicated your level of experience, I think some of the replies might not have been so judgmental.

My Trek has no internal tube connecting the entry and exit holes so fishing a replacement cable through the first time was very frustrating. The top tube is open at the set tube end so I could get a finger in there to guide the cable but it was still a pain. Afterward I used the old cable to guide the new housing and then replaced the inner cable.

The Trek is Al so internal rusting from water getting in through the top tube holes isn't an issue.

To the OP; if your first posting had indicated your level of experience, I think some of the replies might not have been so judgmental.

My Bianchi Veloce has the internal tube. The AL tube bike (it was a Raleigh Technium) that I once owned, well I guess I never actually replaced the housing. Just slid the new cable through. So I guess I assumed they all had the internal tube. My bad.

I had also planned to silver solder some sort of hoods over the openings similar to the ones in the photos posted.

The internal guide tube on my Pinarello is brass. I know of identical arrangements on other Italian-built bikes, a Di Bernardi comes to mind. Point being, I don't think the fittings for this type of arrangement are rare. I know you don't want to spend a lot of money on this, but you might check suppliers of custom steel frame builders (Nova, Henry James, etc) for these fittings. The price may not be too bad, I think it's worth checking. If you're going to braze fittings onto the frame, it would be great if you could use fittings that are made for what you're wanting to do-

EDIT: I see that JohnDThompson's link goes to the Nova site, sorry for the repeat-

If you get the hole started, you can drill the rest of the way on an angle, pretty shallow if you're careful and drill out with progressively larger bits. Just take your time and avoid getting your bit snagged and torquing on your frame.

I had to fish housing through the top tube of a raleigh technium yesterday. No internal guide. Both holes on drive side. Here's what I did:

1. put a little j bend in the end of a brake cable, so that when you fish it through, you can wiggle it so it pokes out the other side

2. grab it with a tweezer

3. cut the bend off the end of the cable

4. cut your housing a bit longer, and grease the outside just a bit (just on the first inch or two going in).

5. thread the cable through the housing and push the housing through the tube. the cable will guide it out the other hole.

6. cut the housing to final length, and you're done! Don't forget to file the sharp edges of the holes down a bit to facilitate the movement of the housing through the holes, and prevent snags.

Good luck.

I currently have three bikes with internal routing in the top tube. Two out of the three have top tube rust issues. Seems like the two holes exposed to the elements is not good. The third bike is fine, but it is only a couple of years old.

I would not wish internal routing on anyone. But if you want to try it, a $20 frame is a good candidate for experimentation.

The first frame is in the acid bath right now, the second frame is next.

Oh yeah, and I am not looking forward to rerouting cables (I pulled the housing and left the cable wire intact, hopefully that will be enough for me to rethread the replacement housing. I didn't think a cable housing would fair too well in an acid bath...