We're spending the day at Mark Purdy's shop, Ifixbyx, to liveblog a P3c Di2 build. Like the P4 build we did a while back, the P3c isn't made for Di2, so it'll require some creativity from Mark to get things routed nice and clean. Feel free to write in with questions here or on Twitter and we'll answer them through the course of the day.
Mark drilled out the cable hole before I arrived. It's an aluminum insert, so no carbon was harmed in the making of this movie.
Well, that didn't take long. Mark's enlarging this hole so 2 cables can come through.
The battery will be mounted on the water bottle bosses and the cable will run through the hole Mark just enlarged.
Mark's going to be fishing for wires for a while.
This whole mess will be shoved inside and live in the downtube.
The cable splits inside, one end goes up the downtube and the other end goes up the seattube. Getting it to split off just right inside is a pain in the ass.
The frame's wired but the battle's only half won. These Shimano Pro bars have an integrated stem. The shift wires will run down the arms and into the integrated stem, then down and out.
A clearer shot of that cable routing.
Two sets of shifters per side and brake cables too. Lots of stuff to route.
Pretty snazzy set of bars. The worst is over, the rest is pretty much a normal bike build.
Mark greases the threads of the BB and the shell. He doesn't believe in using plumber's tape or Locktite. Plumber's tape can tear and bunch up, Locktite can creak and chirp.
What, no power meter on a bike this swanky? (Mark made me type that)
New toys: preset 4-5-6 Nm torque wrenches, $30 each, great for a bike fitter who'd make a lot of changes.
Water bottle bosses usually sit higher up on the downtube, leaving more room for the battery. The second bolt head is going to interfere with the battery, so Mark will have to get a countersunk bolt and countersink the mount so the battery can slide in.
Wires from the bar end shifters exit out the back, will meet up with handgrip cables and 'Junction Box A' (the little controller that lets you tweak the shifting) under the stem.
This is a pretty colossal pain in the ass. There's a free floating nut plate inside the extension that the armrest will bolt into. Mark's gotta get it in position and make sure it doesn't pinch the wire that's inside.
Now Mark's gotta fish the wire out the front so he can plug it into the shifter, then shove the whole mess back in the extension.
A better view of the battery mount problem. Note how the lower bolt interferes with the battery. Mark will use an adapter so that a bottle cage can be mounted, higher up on the downtube.
The shifter has a short cable and a plug, which meets up with the cable routed from the other end. All this will go into the base bar.
Wiring tape covers this run of cable that sits outside the frame. It comes in white, grey, and black.
Cleaning up the front derailer and battery wiring.
Countersinking the battery mount.
The battery mount's turning out to be a bigger pain. It needed a spacer underneath so the wiring could clear.
Done. A ziptie keeps the battery snug.
A Mavic Helium stands in so Mark can set the brake pads. Mark doesn't toe in unless there's a specific problem reported, and even then he says road brake arms are so rigid they're rarely the source of the problem.
Grinding the brake housing nice and square on the cut ensures that the housing is seated properly right from the start.
Mark opens up the stem again to route brake housing. These bars are abusive. The housing runs through the wings, into the stem, and out the bottom near the steerer tube.
Shoving everything back in and cinching it up. If this wasn't a Di2 build there'd only be two pieces of housing running through the stem.
With all those cables and wires the front brake will have to exit through the wing, not the stem. Mark works on fishing the rear brake cable out of the frame.
Rear brake done. Mark was surprised at how good the brake felt considering all the twists and turns the housing had to make. If there had been more drag he might've considered using Nokon housing, which he prefers for braking but not shifting.
Mark drills out an existing hole in the wing at an angle to route the front brake housing.
Front brake done, nice and clean.
After all this mounting a chain seems so mundane. To set chain length, Mark puts the chain on the small ring/small cog, and adjusts the length so the chain clears the cage. He prefers this to the 'big/big/bypass the derailer' method because you won't end up with a too short chain should you switch to a cassette with a bigger granny.
Mark uses this piece of housing to ensure that all his cables are cut to the same length.
Checking the shifting with the real wheel in place. If this were a cabled setup Mark would err on the side of having slightly more tension, so things will settle into the sweet spot over time.
Setting the front brake.
This crazy angled top cap means there won't be any extra steerer above the stem. Mark won't cut this steerer until his client comes in and gets fitted.
On goes the saddle. Mark isn't opposed to greasing the rails, but he doesn't do it.
Finishing off the bar wrap with an angled cut. When taping up with electrical tape, pull hard for a couple of wraps, then finish with minimal tension. This reduces the tape's tendency to unwind.
Front end wiring cleaned up, that's the infamous 'Junction Box A'.
That single wire handles all shift duties.
And we're done, or as done as Mark can be without the proud new owner on the bike. Keep sending in questions and I'll pester Mark to address them. Thanks for following along!