deacon mark

I have a 2013 Wilier GT and it has internal cables. I decided that with winter and 3800 miles to put new derailleur cable and housing on the bike. I had previously replace the rear loop housing about 1200 miles ago and this time thought I might as well do the cable. Well I get in a hurry and all of the internals fall out and I was at it for 4 hours with all kinds or tricks. Finally managed to get the cable to the rear changed and going through the chain stay was unreal. I ended up using some heat shrink tubing to get a wire and the cable to go through and finally get done.

I consider myself a decent wrench and build my own wheels but this was the worst thing I think I have had to deal with. I ended up goggling tricks and tips and next time I will be prepared. The only good thing was that on todays ride I had perfect shifting and no issues. I got rid of the inner tubing inside the chain-stay and I think that was making the shifting not as crisp. This is Shimano 6700 and it has always worked good for me but requires precise set up to get it right.

I am now open to any tips or tricks or even help when I need to do this again. Give a straight shifting system and external cables any day they are so easy to work with compared and even if the cables do not last as long not worth the trouble.

Raiden

Glance back a page or two, there was a very similar thread a week or two ago. Next time, before pulling the cable out of the frame, thread that thin tubing over the cable so it sticks out of each hole, and tape it to the frame as a placeholding cable guide. Then pull the cable.

rpenmanparker 

Or if you forget to do that, you might try doubling the cable you are pushing through so there is a loop in it and grabbing it at the far end with the J-bend end of a spoke or a paper clip bent into a small hook. Then pull the loop out that end and pull the doubled over part all the way through so you only have a single wire inside.

Raiden

That does work, but if you're going to use that method, I suggest doing it with an old cable (as you typically kink the cable pulling it out of small holes), then place a cable guide tube using the old cable, pull out the kinked cable, then thread the new cable.

rpenmanparker 

Yes, that IS a good plan.

FBinNY 

There are all sorts of ways of doing this, and what's best (?) depends on the details, such as the size of the holes in the tubing.

If planning an internal wire, I've found the laziest way is to cut the old wire up near the head (handlebar end), and pull off that housing segment. I trim for a clean cut and leave the old wire in place in the frame, thread the new one through the levers and handlebar/frame segment, and all fittings up to where it will enter the frame.

Then I shrink 8-10" of tubing to join the front of the old to the lead (rear) of the new, and gently pull/push them through the frame until they exit at the back or under the BB. This leaves me with a threaded wire with little effort, and I can finish the rear loop and pinch bolt to complete the job.

The key to this is to get it right the first time, not forgetting a ferrule, or mis-measuring housing, but if so, it's always possible th splice twi wires and work back and forth as necessary.

OldsCOOL

Exactly what I did with my Technium PRE. Use the old cable or guide to support the new ones.

CliffordK

I haven't done internal routing yet... I did read that it is a bad idea to cross the front and rear derailleur cables in the process.

Anyway, most of my cables have a foot of so of extra cable depending on where they're routed to, so I wouldn't be too worried about a kink an inch or two from the end.

rpenmanparker 

I've run crossed wires on externally routed derailleur cables. I wonder why they wouldn't work when internally routed.

Raiden

I'm going to agree not to cross internally routed cables (worse yet, accidentally wrap one around the other), I've seen the front influence the rear shifting. But I have also crossed external cables without issue. I think the difference is where they cross, or how they enter/exit holes/housing.

CliffordK

Yes, a single cross might not be bad... but if you do a cross & wrap, so you end up with the cables on the "normal" side, then tightening one cable pulls the other one and shifting goes haywire.

a77impala

I recently had to replace rear deraileur cable on my '85 Trek 420, forgot it was through the chain stay and pulled it out. Two hours later and many attempts I succeeded by getting very thin piece of wire through, wrapping it around the cable and gently pulling it in. It barely fit through the hole, it took several tries before it slid through. I wrapped about 18 inches of the cable to prevent wire from slipping off.
I'd like to know how this was done at the factory! If I had an air compressor I would have fed some thread into the chain stay and forced it out with air pressure. This is a method used to get a pull string through conduit.

rpenmanparker 

Totally agree. And inside the tube cross and wrap could occur when you are not trying to cross at all. So it would look normal from the outside.

deacon mark

Ok this is strange. I went to all that trouble and now I want to do it again because I think I have the way this could be done easy based on responses. I cut the old cable at the handlebars and then thread the new in all that way to the tube. Then I get some heat shrink tubing and spice the new on the old and then gently pull the cable all the way through. Does this sound like the best approach to splice and like I said I sure would like to give it another try but I pretty sure this is how to beat this ugly repair.

FBinNY 

I gave you that approacem and it does work 90% or the time. The only hitch is very samll holes on someframe fittings where the shrink tubing doesn;t pass well.

OTOH, while this is an easy approach, I doh't think it's so good that you'd want to take apart your prior effort just to try it.

If you do, be careful to feed the new wire while pulling out the old one, and don't tub hard enough to pull the wires out of the tubing. One ,ore hint-- the longer the overlapped tubing the lower the chance of pulling them apart, so don't skimp.

deacon mark

No I am leaving it as is but thanks for input. Another option would be to a long thin wire and use a crimp two splice them together and pull through. I also found a youtube video from Arts Cycle that says use dental floss and attach via a crimp and then us a vacuum to get the dental floss close to the hole. That would be difficult on my frame on the rear stay as is goes all the way back not out the side as some do.

bwilli88 

Try using a Vacuum instead of pressure and try silk thread, it is very light yet really strong

rm -rf

I did the same thing, pulled the rear brake cable out of the top tube of the frame and then found it impossible to get the replacement cable back through from the front. The frame holes are permanent cable housing stops, with a hole just slightly larger than the brake wire itself.

But the LBS mechanic fixed it in a couple of minutes. He threaded that thin plastic tubing from back to front, and then it was easy for me to run the brake wire. Huh. I had no idea how to tackle this.

Here's the details from another thread. This is way easier than using shrink tubing and is less likely to come apart. Your LBS should have this stuff.

Grand Bois

But who has silk thread on hand? If you're a fisherman or dual line kite flier, you may have some Spectra or Dyneema.

FBinNY 

ANY light flexible thread can be blown or sucked through to start the process. It doesn't have to b strong. If necessary, can be used to pull stronger thread through, which in turn can be sued to pull the cable.

Keep in mind that the initial cables for the Brooklyn Bridge were pulled by flying a kite across the East River. Of course, they couldn't pull a heavy steel cable with a kite string, so pulled progressively stronger strings and ropes until ready to pull steel.