Using full cable housing internally

[Dictatorsaurus]

Can someone please share the procedure of routing the internal cable frame ends to route a full housing for the rear shifter cable for the CS-057 frame?

[Jotegr]

I'll be honest, I know nothing about that frame but I do know quite a bit about dealing with horrible internal routing. What's the issue you're having? Most internal routing issues end up getting solved with time, effort, frustration, and those little red connector things that reverbs come with.

[sclyde2]

i have some experience with this.  not the actual implementation of the internal routing with full length housing, but I have experienced issues with this frame's internal routing, so i have done a bit of research on this topic over the years, but not yet implemented.  my FM-057 (pretty sure it is the same frame still) has just turned 6.  it lasted a couple of years with internal cable routing for the rear shifting, but it deteriorated over time, such that i ended up externally routing it.  i did consider the idea you are thinking (trying to get the housing through the frame), but, at the time, i couldn't see how it could be done, and i did read at least one or two stories of people who did it (buried somewhere in the monster thread on mtbr), and i got scared off - they didnt really detail how they did it, what their issues were, but they advised against it.  so i have been running external routing for at least 3 or 4 years now. 

only a couple of months ago, i have become interested in this topic again, as a pretty bad rattle has suddenly developed, and i have traced it to the empty internal routing for the rear shifting, seems to be around the area near where it attaches internally around the head tube area  (i.e. the front cable stop).  i'd love to remove that internal routing tube to get rid of the rattle.  problem with this frame is the access - with the BSA BB shell, there is no access around the BB area, the only access is in through the head tube, and while i have considered drilling out the cable stops at each end (near the head tube, and the one on the chainstay), i cannot get a good enough view (in through the headtube with the fork off) to know for sure if the internal routing tube is attached/glue/fastened somehow around the BB area, so it would be a risk to drill out the cable stops, as, if the internal routing tube IS attached around the BB area, and i drilled out the cable stops, i would end up not being able to pull out the internal routing tube, so it would end up loose in the downtube, probably rattling even more.  so i gave up on the idea again.

but the rattling over the last month is starting to get to me.

your thread has prompted me to have another look at this.

there doesnt seem to be any thorough explanation anywhere online on how to perform this task on this frame.

but, this time around, i found this old thread (surprised i didn't see it before):
https://forums.mtbr.com/29er-bikes/chinese-fm056-frame-internal-cable-routing-flexes-stretches-792079.html

the fm-056 is the same frame as mine (and probably yours), except it has different rear dropout (i think it might be 135mm only).

it sounds the OP on that thread got some good vision of the going ons inside the frame, using an endoscope, but sadly his vids and pics dont seem to be on youtube anymore.  however, i did get a few key takeouts:
- the internal routing tube is NOT attached to the frame in the BB area, so the only attachment points are at the two cable stops (i.e. at the entry/exit points, one at the front, and one on the chainstay),
- so drilling out the cable stops at each end will be enough to detach the internal routing tube from the frame.
After drilling out each end, the internal routing tube would have to be pulled out of the frame, and the only route to do this is out through the headtube.  I am not sure what tool to use to get in through the headtube and grab hold of the internal routing tube, to pull it out.  gonna have to think this through before drilling out.  if i cant find some kind of super long nosed (and curved) pliers, i have an idea that might work: partially thread a gear cable through the tube (from the rear), do some fairly precise drilling/cutting (either with a very small drill, or some kind of dremel attachment) around the inside sides of the rear cable stop (to detach the internal tube from the frame), then drill out the front cable stop (detaching it internally), then push the gear cable the rest of the way, the objective being to get the end of gear cable to poke out through the top of the head tube.  then pulling the gear cable out through the headtube would take all of the internal routing tube out with it (the head of the cable will pull on the detached-from-frame rear cable stop). 

the next step would be to route the housing through the frame.  this would obviously go through from the rear (as i have doubts that just pushing the cable from the front would just magically go out through the rear exit), and there would be a risk that simply pushing it through might not work, as it has to get around the bend in the BB area, and i cannot see if there are any angles in the carbon on the interior of the frame around the BB area, that a cable being pushed through would get stopped by.  internal snags when pushing through housing are often gotten around by putting bends/kinks into the end of the housing before pushing it through, and failing that, pushing through a more easily bent cable (inner) might work, using gravity to help (i.e. have the frame upside down when trying to push the cable through the bend in BB area), then using the inner as a guide to thread an outer over it.  there would still be a risk it wouldn't work.  having said all this, perhaps this routing-of-housing step could be better done if it was combined with the previous step : attach the housing to the end of inner cable that is used to pull the internal routing tube out of the frame - not sure how to get it firmly attached though (i have tried this before using insulation tape, and it almost always does not hold).

the last step would be to get the housing out through the front exit.  this would be quite hard to get it to line up perfectly and go out through that exit (as that hole is the same size as the housing), but i got some idea from one of those threads : have the end of the cable housing behind the front exit (down towards the bottle cage slightly), then push a cable inner through the housing from the rear and then get the inner to go out the end of the housing (inside the frame), the out through the exit (would be much easier to inner cable to do this than housing, as it bends easier so can be directed easier (either with gravity and/or by sticking a wire down through the headtube to try directing/manipulating it), and is thinner so will go out the exit easier), then thread another piece of (short) housing onto the cable inner that is poking out through front exit, then push that housing in through the front exit (so some of the housing is in the frame, some is still outside) then push the "main" piece of housing from the rear until it butts up against the short bit of housing (so the short bit of housing becomes a guide for the main housing), then push it some more (again, from the rear of the bike), and it will come out through the front entry/exit hole.

before the last step (i.e. before the housing is pushed out through the front entry/exit hole), it would probably be a good idea to feed some capgo noise protection onto the length of housing that will reside in the downtube.  this optional step would be pretty easy (push the housing out through the headtube, then thread the noise protection tubing over it), and would virtually eliminate any risk of cable rattle.

as the rattle in my frame is bad as it is, i now feel that i have nothing to lose, so i am gonna try doing the above.  as i have had some pretty tricky internal cable routing jobs over the years now, i am quite aware how difficult, time consuming and, above all, frustrating, some of the above steps are.  am i also aware that there is a risk that i might not successfully complete the above described steps.  eg1. i fail to pull the internal routing tubing out of the frame (but i doubt the rattle caused by loose internal routing tube would be much worse than i have now). eg2. i fail to get the housing past the BB area (in which case, i'll just continue to externally route).

anyway, hopefully you get a few ideas of how you might go about doing this task.  i'll let you know how i go, but it'll probably be a month or so until i attempt it.

the reason this process is so difficult is because there is no access around the BB area.  Just in case they have changed things over the years, and your frame is different to mine, the first thing you should do is remove the BB and see if there is any access (holes) inside the BB shell.  If so, this process might be much easier (the less risky) on your frame than it is on mine.

[carbonazza]

Here's how I would try this.

The tools you would need are the longest brake or shift cable you can get and a powerful magnet.
The idea is to use the cable as the guide for the hose.

Enter the cable from the seatpost. Yes, bear with me 

Guide it with a magnet to the BB, then through the chainstay then to the rear derailleur. Just to see if it goes easily.
Push gently the cable through the seatpost to give some room, but let the magnet pulls it, you'll feel the force or ear it against the frame, if you catch it with the magnet.

Then pull all the cable, and do the same in the other direction, through the downtube up to the top end cap.
The view may be better by removing the fork/headset.

If both directions work, chances are a hose will go through.

Then comes the blue pill-red pill moment.
You remove the existing cable, and drill both ends with a drill that is 0.5mm more than the hose.
When I did that on a 256 frame long time ago, I started with a small drill, then 0,5mm by 0.5mm bigger drills to the target diameter.

From the back enter the longest shifter/brake cable you can get, hopefully more than twice the lenght of the hose.
Guide the cable from the rear derailleur, with a magnet, through the chainstay, over the BB, the downtube to the end cap.

Then from the rear, slide the hose on the cable and start to push it inside the frame using the cable as a guide.
The critical moment is between the chainstay and BB, but with the cable as a guide it should find its way up to the top end caps.
If the cable is long enough, it can exit back from the hose and you can tension it from the top end cap and provide a better guide.
If not you need to be more gentle than using force.

As Sclyde2 said, if there are holes in your BB shell or it is a press fit, it may be much easier to guide the hose there with your fingers.

For the potential rattle, make the hose exit first from the headtube instead, and either buy the dedicated foam in bike shops, or this https://www.aliexpress.com/item/32918353384.html and slide it over the hose to the BB. I don't do it each time.
Then drive the cable through the top end cap to guide the hose, and voilà!

Hum... good luck !

[sclyde2]

I finally got around to attempting this.  i had some degree of success.  my planned approach didnt work, so had to improvise.

the drilling out of the cable stops at the cable entry points (one on the chaninstay near the rear dropout, one one the downtube near the headtube) wasnt that successful.  for both ends, I could not get the drill to all the angles required to separate the internal routing tube from the frame.  i even used a dremel flex extension attachment.  i would recommend having a right angle drill, or perhaps a very small dremel cutting disc (if one exists that is that small) before attempting this.  as a result i made quite a mess of the entry points, with the holes ending up much bigger than the cable outer (i'll have to plug the gaps with some kind of silicone sealant).  i ended up drilling through the side of the inner routing tube, but not cutting it all the way around.  it almost beat me.  after drilling through both ends, which cut around some of the internal routing tube at each end, i got a coat hanger (thick wire), formed it into a hook, fed it into the head tube, hooked it onto the internal routing tube, and pulled hard enough to break the internal routing tube away from the front exit point (where i had part cut it with drilling).  as this was now a loose tube in the downtube, i had to get it out, as shaking it around caused quite a bad rattle (as expected).  thanks to carbonazza's idea to use the access down through the seat-tube, i was able to see the internal cable routing (the very edge of it) when looking down through the seat tube, and i was able snag it with the coathanger (a very small hook, after many attempts), pull it quite hard, and managed to break the internal cable routing at the BB area, and then got the front part of the internal cable routing tube out through the head tube.  so i was not able to retrieve the internal cable routing tube in the chainstay, but i got the part most likely to rattle (the part that was in the downtube).  i was then able to feed cable outer through the rear entry point, and by putting a little kink in it, i was able to push it past the BB and up the down tube, then out the head tube.  after feeding some inner cable into the cable outer, i pulled the outer back into the down tube, then spent quite a bit of time trying to get the inner cable to poke out through the front exit (this took quite a while, used gravity + a coathanger in through the headtube to guide it), and finally got the cable outer out through the front entry/exit point.  all this took more than 3 hours.  i have put the bike back together, shifting seems good, but haven't yet sealed up the gaps around the enlarged holes.  i can see why others have advised against doing this, and i wouldn't do it unless i had the rattling issue, as external routing works fine, and i certainly wouldn't do it on a new frame.  Having said all this, i am glad i did it on my 6 year old bike, hopefully the shifting is good and there are no rattles - plan to test ride it tomorrow.

edit: on the 2nd last step, when i had the cable outer out through the head tube, i pushed some capgo noise protection onto it, enough to cover the length inside the downtube.  this was probably the easiest step of all, and ensures the cable in the downtube wont rattle.

[sclyde2]

test rode bike today (towing kids in a trailer, a bit over an hour, lots of climbing, road stuff with a little bit of offroad).  shifting was excellent (light enough action, and perfect shifts every time) and there were zero rattles.  wasn't a big deal to put some silicon in there to fill the gaps around the cables due to the overly enlarged entry/exit holes.  very very happy with the outcome.  am still very happy with the 057 bike and hope to get another six years out of it.