2014 Giant TCX full cable replacement, part 1: Preparation

In the past, I’ve written about the internal cable routing of Hyro, my 2014 Giant TCX SLR 2 cyclocross bike, as well as walked you through a rear shift cable replacement. However, I’ve never been able to give him a completely fresh set of cables and cable housings. Three and a half years in, he’s been long overdue.

One major reason was simply gathering the supplies and tools needed for the job.

If you’re even thinking of doing this job on your own, invest in a proper dedicated set of cable cutters. Unlike pliers, which can crush cables and housing, these will give you clean cuts by shearing action. I’m using Park Tool’s classic CN-10, which is highly recommended by a lot of mechanics. Jagwire, Pedro’s, Super B, PRO, and other tool makers have their own versions which should work just as well.

Park Tool’s guide to the different types of cable housing, with a cross section of each.

As great as TRP’s Spyre mechanical disc brake calipers are, they explicitly state that they work best with compressionless brake housing. Unlike traditional brake housing, which is spiral coiled along its length, the compressionless stuff more closely resembles shift housing in that it is made of multiple small wires in parallel that surround a plastic inner liner. In many varieties, what makes it compressionless is a woven layer of aramid fibers surrounding the whole thing. (One aramid variant is Kevlar, famously used in bulletproof vests.) This means compressionless brake housing is more resistant to bending, and must be routed as cleanly and with as few abrupt bends as possible.

There are Jagwire full cabling kits that carry their compressionless brake housing. However, they’re way too short for the full-length housing run required on many cyclocross bikes, and I don’t know any local bike shops that carry the “XL” version of these cabling kits – that would’ve worked.

Internally routed cables in a bike frame are a common bugbear of bike shop mechanics. There are many hacks out there that can help decrease the time sink and aggravation of fishing out cables and housing from inside a frame tube…but I say investing in a Park Tool IR-1 internal cable routing kit is the ultimate hack of all. I will be talking more about this tool in the future, but suffice it to say that it is AWESOME.

The final requirement is a set of ferrules, one each for 4 mm (shift cables) and 5 mm (brake cables). These are essentially caps that slip over the ends of the cable housings to prevent them from mushrooming outward. While brake ferrules can be made of plastic, shift ferrules are typically made of metal. On the 2014 Giant TCX, you will need six shift ferrules and four brake ferrules in total, and not all housing ends require them.

As you’ve no doubt picked up by now, preparation is crucial. I doubled up on it by buying shift cables, shift cable housing, and brake cable housing in bulk. I also have a couple road brake cable sets bought as spares. All that shift inner cable and cable housing should last me a few years; all I’ll have to replenish are brake cables and relevant ferrules when my supply runs low.

Finally, since full cable replacement involves removal of your handlebar tape, you might as well have a new roll of the stuff on hand. In a break from tradition, I tried Fabric’s knurl tape this time around.

In the next installment, I will walk you through the brake cable replacement.

Frayed, again

Seven months after I last replaced my frayed rear shift cable, it’s happened again: that old familiar feeling of just nothing happening as I summoned an upshift. In such conditions, I’m effectively riding on just half my cassette, the smaller cogs sealed away until the shift cable finally snaps in two and dumps me on top gear.

Just a fact of life for me, I’m afraid

Fresh rear shift cable getting inserted into a Shimano 105 5700 STI lever

Shimano’s 105 5700 STI levers are infamous for fraying their shift cables around the head area, which I can confirm with my own experience. I’ve already written about the challenge of replacing shift cable on Hyro, which usually results in me lying on the floor, looking at the bike up its bottom bracket shell, while trying to coax rear shift cable correctly into its routing hole in the drive-side chainstay. Ah well, such is the reality of wrenching on a TCX.

Not too long ago, “AngryAsian” James Huang wrote about his appreciation of good old mechanical shifting with cables in an age where electronic shifting is the bee’s knees. For those like me, who ride on frames that have challenging internal cable routing, something electronic like Shimano’s Di2 would be perfect – install the battery, E-tube cables and junction boxes one time, and in theory, you should never have to maintain or replace them. Shifts will always be perfectly indexed once set, and Shimano have even thrown in automatic trimming and Synchro Shift of the front derailleur. Indeed, Di2 has found fans in cyclocross competition, where the maintenance-free nature of the E-tube cables and the increase in frames with internal routing make for a minimum of fuss compared to the punishment the rest of the bike suffers from.

Even simpler still would be SRAM Red eTap HRD, where the control levers and derailleurs talk to each other purely through wireless communication. Sure, you have more batteries with smaller capacity to deal with compared to Di2, but all you’d have to worry about afterward are the hydraulic brake hoses.

The main barrier to entry for electronic shifting, despite all its merits, is cost. Unless you’re looking at the top tier of groupsets and components, electronic shifting is usually not an option. If you were to go with the most affordable route, Shimano Ultegra Di2, you’re still looking at roughly the same cost of mechanical Shimano Dura-Ace, the Japanese juggernaut’s top-tier road bike groupset. This is why many believe that Di2 should be made available at more affordable third-tier Shimano 105 for proper mass-market adoption to increase.

Until then, dealing with replacing cables and fishing them through the frame roughly twice a year is a reality of maintenance. At least I have no battery to deal with, though.

Rear shift cable replacement on a Giant TCX SLR 2

In a previous installment, I walked through the internal cable routing arrangement of Giant’s TCX SLR 2 cyclocross bicycle. Today I’ll show you how to actually replace a rear shift cable on it. You may remember I broke mine not too long ago.

For this job we’ll need new shift cable and a pair of cable cutters. I’m reusing the old cable housings for now, but ideally it would be best to replace those at the same time.

REMOVING OLD REAR SHIFT CABLE

Job one is to undo the bar tape, and either peel back or completely remove the brake hoods. This is mainly to expose the cable housings and the cable exit hole on the control levers. On my Shimano 105 ST-5700 levers, they’re at the bottom of the lever body.

Use the shift levers to release all cable tension by shifting to the smallest cog. This will expose the bulb of the cable head into the cable exit hole to facilitate removal.

Normally you should be able to expose the shift cable, free it from the rear derailleur’s cable clamp bolt, and push it through the housings in order to remove the shift cable from the control lever. In this particular case though, the shift cable snapped inside my right STI lever, so that’s not feasible. I had to pick and pry the cable head bulb with a hobby knife to get it out.

Yep, that’s a nasty fray.

Next, get a paper towel and soak a bit of it in wet chain lube. Take your new shift cable and run its entire length through the lube-soaked paper towel. This cleans and lubricates it.

INSERTING NEW SHIFT CABLE

Insert the shift cable into the exit hole and pull it through the control lever body. Make sure that the cable end is fully seated inside the control lever by pulling it tight.

Next, run the shift cable into a ferrule, then the length of cable housing for the handlebars. Seat the ferrule into the control lever body. At this point, you can return the brake hoods to their normal position on the control levers.

The cable housing runs into the downtube and pops out around the bottom bracket shell area, looping around it before re-entering the frame into the drive-side chainstay. Shortly, this brings us to the most…”involved” part of the whole operation.

Pull out the cable housing from the routing hole leading into the drive-side chainstay. This exposes the ferrule on this segment of cable housing. Push the shift cable through until it comes out of the housing and ferrule.

THE CHALLENGE

Giant uses an internal liner that enters the drive-side chainstay at the rear dropout area, anchors there, and terminates inside the chainstay. When you pull the whole thing out, it looks like this:

The inside of the cable routing hole of the drive-side chainstay has this U-shaped slot that is supposed to both accept a cable housing ferrule and keep the thin end of the liner in place. If it works, it should be easy enough to feed the shift cable in.

In practice, it can get dislodged from there. This is the biggest challenge of the cable replacement job.

If the liner gets dislodged from its retaining slot, you’ll have to manipulate it at the dropout end by pulling it free and turning it around. It feels like a bit of a lottery to get it in, but be patient. The cavity is relatively small so there’s not much place for the liner tubing to go.

Once the liner tubing is sitting where it should, feed the inner cable through.

Continue pushing along its length and it should pop out at the rear dropout area next to your cassette. As you feed more cable, insert the ferrule and cable housing back into the routing hole around the bottom bracket shell until fully seated.

THE HOME STRETCH

We come to the final loop of cable housing feeding into the rear derailleur. This length should have ferrules at both ends.

Run the cable into the barrel adjuster on the rear derailleur, then into its cable clamp bolt.

Seat the final ferrule into the barrel adjuster and pull the shift cable as tight as you can. Get your 5 mm hex wrench and tighten the cable clamp bolt.

You should have a bit of excess cable left. This is way too long, though. All you need is an inch or so past the cable clamp bolt.

Break out the cable cutters and snip off the excess cable. Slip a cable cap on the end and crimp it with the same tool so that the cable doesn’t fray at the end or stab you.

Job done! Now all you need to do is set your rear gear indexing and perform test shifts.