Had the most bizarre wrenching experience yesterday

[weisan]

A friend was having shifting issues so I took her bike home to look at after our ride yesterday.

It was an older model Giant TCR. Up until yesterday, I have never worked on bikes that use internal routing, except the nominal top tube internal on my LOOK which was easy and straightforward, doesn't pose any difficulty at all.

Long story short, I ended up having to replace her rear deraileur cable and encountered some difficulty trying to get it routed. Finally, got it done using the "trick" of tying dental floss to one end of the cable with the idea of sucking the floss out the other end using a vacuum cleaner and then pulling the cable out with it. Well, this is the bizarre part. For a while, I couldn't push the cable through on its own but as soon as I tie the dental floss to it, miraculously, it just came out on the other end without much plodding. I didn't even get to use my vacuum cleaner. So I guess, the key to a easier life with internal routing is tying dental floss to cable. I get the message now.

I can understand and appreciate the sleek and cleaner look of internal routing and it has probably improved in its design, ease of assembly and application since my friend bought her Giant several years ago.

[Gummee]

Yeah, sometimes you get lucky.

AFA that last sentence: uhhhh no. They haven't improved anything with internal routing since that Giant. If anything, it's gotten worse

M

[peanutgallery]

Plastic cable sheathing and the park internal kit in a pinch

Internal is way cleaner looking, you just have to think ahead when working on it. For the record, internal cabling on $500 Boomer Bikes are completely unnecessary

[eddief]

https://www.parktool.com/product/int...ing-kit-ir-1-2

[AngryScientist]

i've been working on cars, boats, motorcycles, jet skis and bikes for a long time.

over the years, i've resorted to all sorts of crazy tricks and hacks to get the job done, and re-purposed a whole bunch of household items to "no-traditional" use, haha.

[Veloo]

Haven't actually worked on many internally route bikes myself.
A 90's steel frame with SL tubing I owned had internal top tube routing but even that had internal guides so it was a no-brainer to fish a cable through.

I just assumed today's $3K+ carbon frames integrated some kind of routing (despite the additional weight) to make life easy(er) considering the money spent on them.

[jbay]

Originally Posted by weisan

So I guess, the key to a easier life with internal routing is tying dental floss to cable. I get the message now.

What type of dental floss do you recommend?

[choke]

https://youtu.be/smZA9Jv3qH0

[dem]

So I've only replaced 1 internal cable, and once a cable is in there, replacing seemed trivial - cut off end of cable, slide cable liner tubing over the whole internal cable til it pokes out the other end, remove old inner, insert new inner, pull out tubing?

Is there some reason this is more challenging on other bikes?

[Andy sti]

Originally Posted by dem

So I've only replaced 1 internal cable, and once a cable is in there, replacing seemed trivial - cut off end of cable, slide cable liner tubing over the whole internal cable til it pokes out the other end, remove old inner, insert new inner, pull out tubing?

Is there some reason this is more challenging on other bikes?

It’s more challenging if you don’t do that first.
Yes, you described the proper way.

[steelbikerider]

I have built up about a half dozen used ex pro team bikes and a couple of used tt frames. For whatever reason NONE of the pro team bikes had a single cable or liner or even cable fittings left and all had been used, some extensively. The only saving grace was that the bottom bracket wasn't installed or was bearings only and no sleeve. Some took 2 hours, others 30 minutes and the cables came out right where they were supposed to the first time. TT and aero bikes with all cables going in behind the stem on the top tube are the worst.

Needle nosed pliers with an angled tip are a great help.

[redir]

Magnets work well too.

[cmg]

You could also cut off the ball/barrel lead piece at the shifter and tape the new cable to it and pull it through to the derailleur.

[benb]

I have been procrastinating changing the cables on my Trek Domane for a long time over this.

I have all the new supplies sitting in the garage and have still not started it a month later. (It probably should have been done years ago)

At least the Trek has a removable panel under the BB so hopefully it won't be too bad.

This stuff just happens with complicated wrenching though. My Honda motorcycle I used to have had 25 different things on it that were about 10x as ridiculous as anything to do with internal cables on a bike though. 36" long screwdriver to get to throttle body retainer screws? CHECK. Drain clutch hydraulic fluid and remove clutch slave cylinder to change the chain & sprockets? CHECK.

[Spaghetti Legs]

Originally Posted by dem

So I've only replaced 1 internal cable, and once a cable is in there, replacing seemed trivial - cut off end of cable, slide cable liner tubing over the whole internal cable til it pokes out the other end, remove old inner, insert new inner, pull out tubing?

Is there some reason this is more challenging on other bikes?

There was a guy named Seldinger many years ago who, if he didn't invent it, managed to get his name applied to the technique of placing medical tubes and catheters into difficult spots over a wire. it's used for all kinds of stuff now but I'm not sure if he or his family get a cut. Anyway, same concept as this.

As an addendum, it's a nice touch, if you sell a frame with internal routing, to leave the outer cable, or some other guide wire, in place for the new owner.