Just picked up a Trek 2100 Composite and was all like, "Ooh! Internal cable routing!" Pulled out the cable and housing to see if it needed replacement but they were clean as a whistle; when it was time to put it back in, it was one of the most aggravating things ever . Here I was, thinking that the internal routing was one solid tube but I've come to find out that they're possible just little rings inside to help facilitate the guidance. Tried the vaccum and string method but that didn't work and I didn't have a strong enough magnet to lure the cable through the top tube. Finally, I did a coat hanger-like method to pull the cable back from the other side, but now my brake lever has 1/4 of initial free play and it still doesn't brake as good as before, which leads me to think that the cable skipped one of the rings inside the top tube and is arching over it instead.

Any tips?

I never heard of rings inside a tube. Usually when a housing runs through a frame it just runs through the frame.

I would suspect a crimped cable or it just isn't adjusted correctly.

Ugh! No tips for your Trek Composite. But whenever I dealt with internal routing (my GT, Vitus, Techniums), if the cable housing is ran full length through a tube, and you desire to replace both cable and housing....
cut the ends off the cable and secure it stationary. pull the housing out leaving the old cable as a guide for the new housing. Slide the housing through the tube.
Then secure the housing and pull out the old cable and replace with a new one.
This takes minutes. Without a guide, it'll take hours fishing and poking.

Good luck!

+1 I actually insert a new cable from the handlebar end, and then thread new housing back over the new cable.

The worst one I had was a 1989 Trek, where the housing was seized inside the top tube. Bike had been stored in a dirt floor basement for years, so corrosion was everywhere.

Hmm I will tackle this with new housing and cable tomorrow morning. I'm hearing the housing getting stuck in the middle of the top tube so that's why I was thinking there were rings in there. Thanks for the words of encouragement.

Some builders from back then like Mike Howard (Medici bikes) actually brazed in what looks like copper tubes in the frame tubes for his Aero style bikes. I tested both internal cable routing for both the rear brake and the shifter cables and all I had to do was push the shifter cables and brake cables through one end and they just pop up on the other end. So as long as it's done right, internal routing should not be a problem....

Chombi, you're one of the lucky ones (me, too - my Spinella is similarly equipped with an internal guide tube)! Unfortunately, a lot of builders simply drilled two holes, brazed a couple fancy (or not so fancy) fittings at either end and left it at that.

I had the devil of a time with my old Tommasini Super Prestige when I pulled the entire cable and housing out; probably took me 3 hours to get that thing back in

Good luck, OP, 'cause I think the only answer is trial, error and time...

DD

The OP must have the housing and cable kinda kinked up in the top tube so there might be a coil looped up in there that's causing the not so positive initial pull feel at the lever. I suggest that he grab the housing at both ends near where the comes out of the top tube and try to see if he can maybe pull that kink out. He should feel the cable and housing get longer if there is a kink in there.
I also doubt if there are "rings" inside the top tube as that's just the dumbest thing that a bike manufacturer can do to design internal cabling for their bikes and how the heck can they even attach small rings deep inside a top tube??......

You can use a thin wire (not cable) as a lead and then push the housing over it, then take off the wire and insert the cable.

When I built my frame and used internal routing. My instructor Doug Fattic wouldn't even let me use those generic braze ons where you run full housing through the top tube. Like this.


Instead he had me use a brass tube that went from one machined cable stop to another so no housing is ran internally. Just feed your cable and no messing around trying to fish it out the other side. Very clean and hassle free setup. Took a little longer to do well worth it in the end. Also I notice the paint on the edges of those are chipped from the housing moving around.

We still have to mess around with it at work as some new road frames run cables internally but no housing or guide tube. It's not that bad to setup but some bikes can be a royal PITA.

Kestrel 200(3) cable and housing, about 20 min each w/coat hangar.
Kestrel Talon cable only, stops are removable on each end, about 20 min w/coat hangar
Kestrel RT700 cable only, " " " " " etc.

Paramount OS-3, cable and housing, about an hour with a coat hangar
Paramount OS-7, same as the OS-3

Simoncini had a ferrule built in at each end, brazed in, completely stopped up.
No inner tube. I had to drill out the ferrules on each end, then use a coat hangar.
About 4 hours.

It's always something.

This all sounds like a nightmare. Glad I haven't had to deal with this one (yet).

I have heard of, but not tried, using a needle and thread. The needle acting as a plumb bob. Hold the bike so the top tube is vertical and drop the needle in (attached to the thread....). Heard this trick after spending 3 hours re-threading the Teflon housing in a 2012 Madone 6.2-lost the housing inside the CF frame to start with.

I've done that with a shifting cable through the chainstay on a couple mid 80s Treks.

I threw in the towel on my Trek 560 and had a frame builder braze a cable stop on the chain stay. Smoother shifting and no hassle.

Internal brake routing in my 979 is no trouble at all when changing out cables. I don't know if there is a guide tube or not.

The first time I dealt with it, I was using a NOS shifter cable- it had been coiled for 20 years. The needle/thread trick really saved me on that one- HOWEVER, when I replaced that cable, I used a new cable- and despite all my hesitancy, I turned the bike on end in the stand, dropped the cable in and it went right on through.

Since then, I've had no issues getting it through there.

My daughter has a Nishiki NFS B with internal cable routing and my new(to me) Olmo has internal cable routing. Both have tubes that connect each end. In each case I was surprised because the LBS guy told me never to buy a bike with internal cable routing because they dang near impossible to feed out the other end. He was running a Trek shop.

I have heard back before Trek bought Klein that they had a plastic tube inside than ran end to end.

If you have a good magnet, you can let a cable end sit for a few minutes on the magnet. Feed your cable from one end to the other, then take the magnetized cable and feed it into the end that you want you cable to come through. If you can get the ends to touch and have a feather touch, you can push/pull the cable through.

No - the bare frames came with plastic sleeves to route the cables through - but then you take them out and save them for when you're going to do a cable replacement. (snip cable at far end, slide sleeve over cable through frame, remove old cable, insert new cable, take sleeve back out). You can kind of see them in my attachment. Once you got the cable in there - no housing or sleeve inside the frame.

The trouble comes if you forget or break a cable. It's a hassle but "dang near impossible" isn't accurate at all. I used a piece of copper wire the one time it happened to me - fishing the wire to the hole took about half an hour.

SUCCESS! Trek 2300 Internal brake cable routing SOLVED

Aluminium lugs and carbon fibre top tube.

I finally got my hands on a Trek 2300 Composite. Gorgeous carbon tubes and purple aluminium lugs, forks and stays... thing of beauty. Sadly the rear brake cable had been removed and no string fish left behind. I googled the problem and was brought to a bike forum string discussing this exact problem.

You will need:
* Spool of thread
* Vacuum cleaner
* Brake or shifting cable
* New cable housing

I put the frame in my Park bike stand. Rotated it so the top tube was vertical (front forks up - chain stays down).
Get a spool of good quality nylon or poly thread (stole a spool out of my wife's sewing kit)
Pull out about 3 or 4 feet of thread and thread it into the top opening near the head tube.
Take your vacuum cleaner with crevasse tool installed, turn it on and hold it over the bottom hole near the seat tube.
Watch the thread get sucked in through the top... pull the vacuum away from the bottom hole and Poof...there is your thread!
Tie on a spare cable to the bottom end of the thread (I used a shifting cable).
Pull the thread and push the cable up through the bottom hole... up the top tube and out the top hole.
Now you have a cable running through the openings and top tube.
Insert the top end of the cable into your cable housing and carefully push the housing into the top hole and into the top tube.
Keep pushing the cable housing into the hole until you feel it hit the other end.
Left hand on the cable housing - top end and right hand on the cable coming out the bottom hole... jiggle and push jiggle and push until the cable housing comes out the bottom hole.

Voila!!


A couple of things I learned along the way:
The routing in the 2300 is for the whole cable housing and cable. There are no cable stops. The hole is big enough for good quality brake cable housing to run the whole length internally.
People give up on this quickly and the vacuum cleaner fix works like a hot darn. Don't give up!!

I heard Trek made good bikes.

Myth busted.