Changing drops to flat bars on a road bike.

[Geoff Crowther]

Send us a photo of the entry and exit points and lets take a look. The cable HAS to have a housing. It is there somewhere.

Cheers. Here you go then:

First, entry point where rear brake cable goes into front of top tube. You can see the alloy ferrule at the end of the outer, showing that it ends where it seats in the frame.

Next, this the point where the rear brake exits the back of the top tube. There's a plastic moulding surround the hole.

And this is where the gear cables go into the top of the downtube, one on each side. Again, there seems to be a ferrule at the end of the outer, just inside the frame.

Finally, here's where the two gear cables come out at the bottom of the downtube.

I have to admit, it almost looks to me as if, once everything's freed off and the outers are out of the way, you might be able to tape the new cable to the old and pull it through. What do you reckon? Everything I've read via Google refers to the use of thin tube straws fed over the existing cable before removing it.

 

[Yellow Saddle]

OK, I now what what's going on in there.

Inside the frame tubes, the cable follows a straight line from entrance to exit and thus needs no housing (outer cable) from point to point inside the frame.

Getting the new cable through is a bit of a mission, but with some innovation you can get it done.

1) The downtube route is easy, you'll fiddle a bit and with gravity, a torch, a tweezer and some swearing, the cable will emerge at the bottom of the BB. No problem,
2) The top tube route is more difficult but not impossible. The entry point is easy, just push it in. The exit point will require that you remove the black plastic cover I can see in the foto (out of focus) just behind the cable. If you remove that, it reveals a large gaping hole. With the Frame upright so that the fork is pointing to the ceiling, gravity will help you get the tip of the cable to pop out or close enough to hook it. Then you insert the plastic cap over that and the cable housing in the cap.

Easy peasy. Don't worry but don't sue me if you sweat a bit.

It helps if you hold the new cable next to the frame's entry and exit points and mark the position that will be at the entry point when the tip of the cable is at the exit point. That helps you tell whether you're overshooting or undershooting. Just mark it with a felt tip or such.

Edit: Just one more thing. There is a chance that the two gear cables can cross inside the frame. Avoid that by testing for it. You do this by pulling on the two cables where they exit just before the slider. Hold the two with tension in your hands. Wiggle the one side and see if you can feel it in the other hand. If you can, untangle it. Both must follow a straight line and not cross each other.

 

[Yellow Saddle]

There are some diabolical internal routing designs out there but this one isn't a problem. Quite elegant actually. The worst of the worst is a Niner carbon MTB frame where the cable guides/slides are inside the frame and are out of sight. To make it even worse, the bladder used to keep the carbon tube in shape whilst the resin is setting, is left inside the frame. Although it is plastic, it is hard and resin-encrusted and in the way of everything you try and do. Eventually I created a tool that was a large version of a dentist's root canal tool (an auger) to remove the plastic and then another tool to catch the cable and drag it out. I made quite a bit of money from this because I could charge half the labour anyone else could charge to do the job. By a bit of money, I mean enough to buy two nice beers or so. The tool cost me the equivalent of 30 beers....

 

[Geoff Crowther]

OK, I now what what's going on in there.

Inside the frame tubes, the cable follows a straight line from entrance to exit and thus needs no housing (outer cable) from point to point inside the frame.

Getting the new cable through is a bit of a mission, but with some innovation you can get it done.

1) The downtube route is easy, you'll fiddle a bit and with gravity, a torch, a tweezer and some swearing, the cable will emerge at the bottom of the BB. No problem,
2) The top tube route is more difficult but not impossible. The entry point is easy, just push it in. The exit point will require that you remove the black plastic cover I can see in the foto (out of focus) just behind the cable. If you remove that, it reveals a large gaping hole. With the Frame upright so that the fork is pointing to the ceiling, gravity will help you get the tip of the cable to pop out or close enough to hook it. Then you insert the plastic cap over that and the cable housing in the cap.

Easy peasy. Don't worry but don't sue me if you sweat a bit.

It helps if you hold the new cable next to the frame's entry and exit points and mark the position that will be at the entry point when the tip of the cable is at the exit point. That helps you tell whether you're overshooting or undershooting. Just mark it with a felt tip or such.

Edit: Just one more thing. There is a chance that the two gear cables can cross inside the frame. Avoid that by testing for it. You do this by pulling on the two cables where they exit just before the slider. Hold the two with tension in your hands. Wiggle the one side and see if you can feel it in the other hand. If you can, untangle it. Both must follow a straight line and not cross each other.

Thanks very much for that. It's not only informative but easy to understand too (you'd make a good teacher). Dare I say now that I actually have all the information I need to tackle this job. Now I just need to decide if I can fit it in before I set off on my End to End in two weeks time. Do I order the stuff now; it should come in a few days. Might do that, then decide when to tackle it. It's ok Yellow Saddle, you don't to answer all this rhetorical rambling .

I'm really grateful for all your, and others, help. Prob'ly owe you at least a coupla beers .

I never tire of saying this: where would I be without CycleChat?
Cheers!

 

[Cyclist33]

OK, I now what what's going on in there.

Inside the frame tubes, the cable follows a straight line from entrance to exit and thus needs no housing (outer cable) from point to point inside the frame.

Getting the new cable through is a bit of a mission, but with some innovation you can get it done.

1) The downtube route is easy, you'll fiddle a bit and with gravity, a torch, a tweezer and some swearing, the cable will emerge at the bottom of the BB. No problem,
2) The top tube route is more difficult but not impossible. The entry point is easy, just push it in. The exit point will require that you remove the black plastic cover I can see in the foto (out of focus) just behind the cable. If you remove that, it reveals a large gaping hole. With the Frame upright so that the fork is pointing to the ceiling, gravity will help you get the tip of the cable to pop out or close enough to hook it. Then you insert the plastic cap over that and the cable housing in the cap.

Easy peasy. Don't worry but don't sue me if you sweat a bit.

It helps if you hold the new cable next to the frame's entry and exit points and mark the position that will be at the entry point when the tip of the cable is at the exit point. That helps you tell whether you're overshooting or undershooting. Just mark it with a felt tip or such.

Edit: Just one more thing. There is a chance that the two gear cables can cross inside the frame. Avoid that by testing for it. You do this by pulling on the two cables where they exit just before the slider. Hold the two with tension in your hands. Wiggle the one side and see if you can feel it in the other hand. If you can, untangle it. Both must follow a straight line and not cross each other.

***

Translation: Get a bike shop to do it.