Today we’re going to do a live build of Mark Purdy’s personal CX bike, a LaPierre cyclo-x superlight aluminum frame. Caveats first. This is Mark’s personal bike, and he’s going to ‘drill the shit out of it’ to make it all internally routed. He will never sell this bike, and he knows full well he has voided the warranty and he’s willing to accept the risk of the frame cracking. He just wants to try to do some crazy shit. So here we go.

And there’s hole #1. A wire will go down the stem, into another hole in the steerer tube, and exit here into the downtube. The upper hole will be drilled after the stem height is determined.

Another hole. The wire will exit here, then…

…enter and exit the chainstay.

Shimano’s new CX brakes. 

DT R1800 wheels, tubeless and affordable at around $600. 

Brake chatter can be reduced by shortening the length of cable between the hanger and the brakes. Mark is going to use a hanger that bolts to the fork crown (instead of its customary location at the top of the head tube), so he’s drilling this hole through (it’s a hole for attaching a cable catcher).

That’s an aluminum fork crown he just drilled out, not carbon!

There’s the hanger installed. Shortening the free cable run will reduce brake chatter.

Fitting the front end, this will tell Mark where exactly to drill the steerer tube and bars.

Finding the location of the upper hole.

Time to drill five holes. Two behind each shifter, one in the middle of the bars leading back into the stem, one on the steerer tube, and here on the seat tube leading to the front derailleur.

Action shot!

The holes in the bars. Mark drilled below the attachment point for the hoods to minimize stress on the bars when he’s on the tops or the hoods.

Feeding the wire through the chainstay’s going to be tough. Mark’ll have to route a guide cable through first, tape it to the wire, then drag it back through. He’s expanding the hole to make the process easier.

Spoke too soon. That sucker went right through no problems. Mark is going to use red Sugru to seal the holes. Time to watch the Vuelta stage finish!

Mark has chosen to have junction box A live inside the stem, so he won’t be able to adjust the shifting easily once the bike’s built. Now he’ll build up the rear end of the bike, get the shifting tuned, then complete the front end.

Dedicated Shimano crankset with 46-36 rings. Now you don’t have to buy a road crankset and change the rings.

Mark wants to mount the battery nice and low, so he’ll install a couple of rivnuts on the downtube. Unfortunately he only has 5mm rivnuts and the mount takes 4mm bolts, so he’ll have to grind out the mount.

Two holes for rivnuts, one for the wire.

Popping in the first rivnut.

Grinding down the heads of 5mm bolts so they’ll sit flush in the battery mount. If they protrude the battery won’t be able to slide in. 

One bolt done, nice and flush.

Ultegra connectors are nice and thin. A 13/64" bit is all it takes.

Mark says the worst is over (we’ll see about that). The rear end is all connected, he’ll connect the shifters just to make sure everything’s working before pressing in the BB.

Pressing in the BB86 cups.

Front derailleur installed, using Shimano’s clamp. The clamp is shaped so that the set screw on the derailleur pushes against the clamp instead of the frame.

Fine tuning the shifting with the shifters hooked up but not fully installed. Once this is all set Mark will route the bars and finish the front end.

Bahn mi and bubble tea lunch break!

Normal bike building stuff now, cutting a steerer tube.

With the lower bearing sitting on the fork crown, there’s just enough space to slip the fork into the headtube with the wire alongside.

The other end goes into the stem.

Now the fun job of routing the wires through the bars. Mark runs a brake cable through first as a guide. Here he’s trying to fish it out of the middle hole.

Tape the end of the wire to the cable and pull.

Plugging in the shifter with the dedicated tool.

Plug the front to the back and it’s done. The shifters work, and amazingly the wire crossing from the steerer to the downtube doesn’t affect the turn radius at all.

Cabling up the brakes.

These brakes come with 3 different size spacers. Mark is installing a narrower spacer to bring the brake arms in for more heel clearance.

Setting up the front brake. Note the extremely short run of cable from the hanger to the straddle.

Sugru-ing the short runs of wires on the outside.

And that’s pretty much it. Kinda cool how the only thing visible coming out of the front end are the two brake cables.

Wrapping the bars with Arundel tape, which Mark finds to be the greatest of all bar tapes.

And she’s done! Mark just needs to add sealant and seal the tires, add pedals, and he’s done. Thanks for following along.