The early adopter dilemma, part 3: “This one goes to 11”

Previously I wrote about the history of disc brakes on road bikes, and how Hyro was a technological dead end born from their introduction. Given all that, I went ahead and turned Hyro into the most versatile bike he could be.

All these parts will go onto Hyro.
A last look at my Shimano FD-5700-F front mech. This was the last 105 unit that didn’t have the groupset logo engraved into the cage; it was on a sticker that had come off a long time ago.
These TRP Spyres have served me well.
Hyro shorn of his drivetrain and braking hardware.

Doing that involves stripping almost everything out: the TRP Spyre mechanical disc brake calipers, the Shimano 105 5700 drivetrain parts, the STI levers, and the Jagwire compressionless brake cable housings. The only things left were the Shimano 105 FC-5750 crank and the bottom bracket it spun in. Despite the deep gouges and scars, it had fresh chainrings.

The Shimano CS-HG700-11 cassette broken down into component pieces. All but the largest three cogs are individual.

I previously remarked that Shimano’s CS-HG700-11 cassette was the only way to preserve my current wheels, and that turned out to be true. It fit onto my 10-speed freehub with no drama at all. Off to a good start, then.

Next, the ST-RS685 STI levers and BR-RS785 brake calipers went on. I did the front one first, since it was a more straightforward external routing job for the front brake hose. Giant gave this TCX frame a cable guide that bolts onto the underside of the fork crown to hold brake housing or brake hose in place. In the end, it worked, although I’m convinced the brake hose is about 5 cm too long.

This bolt-on front brake cable/hose guide lives underneath Hyro’s fork crown.
The hydraulic brake J-kit’s pre-installed front brake hose is a little too long. Ideally that lower run should hew closer to the left fork leg.
Photo taken from the other side. All that excess brake hose will flap in the wind. As this is an external run, this should be easy enough to shorten.

Hooking up the 105 FD-5801 front derailleur was my next job…and this was pretty confounding. Because the FD-5801 now sports onboard cable tension adjustment, I could dispose of the inline barrel adjuster, but the way you cable these new cam-actuated front derailleurs is just so strange. The shift cable is pinched by a plate that is held on by a bolt, as before. However, the pinch plate itself is pushed by the cable tension adjuster grub screw as you turn it in to adjust. All this time, the end of the gear cable is supposed to go around the top of the derailleur. A lot of head-scratching occurred here, and it doesn’t help that peeling the ST-RS685 brake hoods to expose the cable exit port also blocks the action of the shift levers, leading you to think that there’s something wrong with them.

Despite the older model name and groupset logos, this Shimano 105 FD-5801-F front derailleur is identical to the newer FD-R7000-F unit.
Mounting this thing and setting its cable tension is a very different ball game from Shimano’s older front derailleurs. Follow the instructions!

Next was the rear brake caliper. This is where the split nature of Shimano’s J-kit OEM brake package was very helpful, especially since the TCX frame has pretty fancy/irritating internal cable routing. Since the rear caliper wasn’t yet hooked up to a brake lever, it was much easier to route the hydraulic brake hose through the holes of the frame. As before, Park Tool’s IR-1 internal routing tool was a godsend, literally pulling the brake line through the frame with the guide cables and guide magnet. Shimano BH59 brake hose is also much more flexible than Jagwire KEB-SL compressionless brake cable housing.

Unlike in this photo, I had to route the brake hose in the opposite direction: from the chainstay, through the frame, and up to the STI lever. In both cases, Park Tool’s IR-1/IR-1.2 cable routing tool makes the job much easier.

Making the right ST-RS685 STI lever talk to the 105 RD-R7000-GS rear derailleur was the next major challenge. As with the front derailleur, cabling this thing was also pretty strange, mainly because of how the shift cable exits the TCX’s rear chainstay and where the cable entry port now sits on the RD-R7000. This required a rather tightly bent section of shift cable housing: generally not recommended, but here it’s almost a requirement. When you do cable it up, the excess cable run is hidden underneath the RD-R7000’s linkages, so it ends up hitting your spokes as you do your indexing and test shifts…until you finally cut the excess cable and bend it out of the way. Older derailleurs also had a more finger-friendly barrel adjuster for cable tension adjustment, too.

Left uncut, as usually done on installation and cable replacement, the RD-R7000’s shift cable is guaranteed to run foul of the rear wheel’s spokes. Very strange decision by Shimano here.
This barrel adjuster is quite a step backward vs. older rear derailleurs. It’s much harder to turn, as your fingers have less purchase on what little knurling it has.
This tight twisted loop was the best way I could think of to run the shift cable between the RD-R7000 and the TCX’s chainstay-mounted shift cable port. Fortunately, it works.

Finally we have the J-kit connection of the rear brake caliper to the right STI lever. At the caliper end, you take off the rounded black cap, which exposes a cleanly cut brake hose with a seal on it. At the STI lever end, you twist and pull off the yellow plug…and this reveals a hose nut socket at the end. Plug the two together and tighten the hose nut against the J-kit connector with wrenches, while dealing with the slow trickle of mineral oil. If all goes well, you should get a good connection with no leaks and no need for bleeding…which was what I got. Hurrah!

The round black cap on the foreground is part of the brake hose, as routed from the brake caliper through the frame. The yellow cap on the background is from the STI lever.
Removing the black cap reveals this white seal. Removing the hexagonal yellow plug reveals a modified Shimano 8 mm brake hose nut, where the end with the white seal seats into.
Here’s the finished J-kit “easy hose joint” rear brake connection. Note the wrench flats which I’ve conveniently scuffed up.
Even with some exposed threads on the hose nut, this worked out very well and I have had zero leaks after installation.

That should have been the end of it, but I found terrible brake rotor rub at both ends while centering the calipers. I ended up having to take out the wheels and brake pads, and pushing back the pistons on the BR-RS785s with tire levers to reset them to their starting positions. Pads and wheels reinstalled, I repeated the caliper centering and it now worked well.

You could imagine my excitement to ride Hyro after this lengthy upgrade job. Unfortunately I succumbed to sickness shortly afterward. Riding impressions will have to wait until next time.


4 thoughts on “The early adopter dilemma, part 3: “This one goes to 11”

  1. I’ve just purchased this exact frame and will be building it up to have a go at cyclocross. The intention is to add hydraulic braking so your detailed articles will be extremely helpful – thanks so much.
    As an aside there are 2 holes beneath the non-driveside chain stay, mine are exposed whilst yours have rubber grommets, do you know why they are there?


    1. As far as I have been able to tell, they are mounting points for an external Shimano Di2 battery. You have that option of upgrading to electronic shifting that way. It also helps that the TCX routes all its cables internally, so Di2 e-tube shift wire should remain well protected.


  2. AppreciAted the thorough write up as I embark on a similar upgrade to my Defy Advanced today – albeit JUST levers and calipers. While I am NOT upgrading the existing RD5800, I have installed several of the newer Shadow RD on frames (RX8000 and RD7000) and must comment that you can/should shorten the loop from frame to RD considerably. The section of housing is specifically designed for tighter loops OT-RS9000.


    1. Interesting. I’ll try that. I’m about due for cable replacement soon anyway so might as well look into any chance of making the cable run neater. Thanks!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.