Build log - Cinelli Veltrix Disc Di2

Updated April 15, 2022 by BetterShifting Terry

I don't buy a new bike often, so when I do, I want to make it special. While there is nothing wrong with black bikes - I've owned a lot of black bikes - I wanted something with a bit more colour.. something different. Something that really pops.

To me, this Cinelli Veltrix Disc is just that.

Cinelli Veltrix Disc Di2

Full disclosure: Some of the Di2 parts in this build were supplied by Shimano EU. I have not been asked to write positive reviews or promote these parts in exchange. As always, any opinions expressed here are my own, not influenced by or paid for by anyone.


Before I walk you through the process of building up this bike, here is the list of components I've used in this build. It should be pretty much complete, but if you feel there's something missing do let me know using either the comments section below or the contact form.

Of course a bike is built up out of more than just Di2 parts, so I'll list the other components as well:

Finally, I am currently running wheels I built myself a few months ago, they are Duke Road Runner 30 rims and orange Hope RS4 disc hubs, laced up with Sapim CX-Ray/CX-Sprint spokes and brass Sapim nipples.

There's a pretty long list of tools I used, but I'll link those at the bottom of the page. For now, let's walk through the build process.

Note that I am not a bike mechanic, so anything you read below is my personal preference and not necessarily the best approach to building a bike ;-).

Skip ahead

If you feel like skipping ahead, here are links to the relevant section:

Cut that fork steerer tube

When I build a Di2 bike I like to get the wiring done first. This is generally what takes the most time, getting all wires through the right ports and making everything look tidy.

The starting point for all Di2 wiring is the handlebar area, so let's start by cutting the fork to an acceptable length. This is what it looked like uncut:

Cutting a fork steerer requires you to measure carefully. You definitely do not want to cut it too short.. there is no way to glue that carbon back together into something that won't kill you on the first ride.

Measure twice, cut once.

I used the Park Tool oversized saw guide, a workbench, some bubble wrap to protect the rest of the fork and a mask. Yes, I wore a mask. Not everyone will, but I feel it's better safe than sorry - especially since I had the mask already.

In this particular case I wanted to cut the fork just right, so that I could use one spacer below the stem. This is the end result:

Next I put the stem and handlebar on the bike. Since this is a full carbon fork you don't just shove a star nut in. You use an expansion plug instead. I then put the Vibe stem cap on and that's it - done.

Wiring up the handlebar

If you've ever looked at Shimano's dealer manuals and looked at the wiring diagrams you might have noticed they use the EW-JC130 Y-splitter cable to connect the EW-RS910 junction.

However, I decided not to. I do not like the way it looks and I did something similar to what you can see GPLama do in the video below.

In my specific case I connected the Wireless Unit to the left shift lever and then connected that to the right lever. The right lever is connected to the EW-RS910 bar-end Junction and from there I run a 1200mm EW-SD50 wire to the internal junction B.

There are both advantages and disadvantages to this approach. The most obvious advantage is that it looks a lot better than using the Y-splitter. You don't need an inline EW-JC200 junction and the Wireless Unit is hidden away as well.

The disadvantage of not using the Y-splitter is that you only have one E-Tube port left to plug a climbing shifter or satellite shifters in. I don't see this as a problem, but this will be different for everyone.

My wiring diagram looks like this:

Next up was routing the electric wires and hydraulic hoses through the handlebar and into the frame. I used the excellent PRO Internal Routing Tool for this and while you can usually get away with using a piece of string or a DIY routing tool, I decided to use this one.

Routing Di2 wires through handlebars usually isn't that hard, but the hydraulic hoses can be a lot tougher. They're not as flexible and may need some more persuading to go around tight bends.

Yes, that is a different frameset. I originally planned to build a different bike, but asked for a refund after I had to warranty-return the frame twice. Some of the images on this are from my first build.

Connecting the brake hoses

When you buy a new set of ST-R8070 levers they come with the easy hose joint system, meaning that you can just plug it in, bleed the system and you're done. Of course if the supplied hoses are too long you'd probably want to shorten them and in my case I used levers I had installed before and I replaced both brake hoses.

I therefore had to install new inserts, olives and connector bolts.. and cut the hose to the correct length at the brake calipers. I then fully bled the system.

First I routed the hose through the handlebar, to the shifter. I then used Shimano's TL-BH62 Hose Cut and Set tool to set the connector insert.

You put the hose insert in the little notch on the press block, just like this:

Then, with the hose run through the tool and the press block inserted, just squeeze the tool and it'll press the connector insert into the hose. Alternatively, use a vise and a hammer.

That's it! The just slide the connecting bolt and olive over the hose, lightly grease them and tighten to 5-6 Nm using a size 8 open ended spanner.

Finishing up the front of the bike for now, I swapped out the cable ports on the drive side of the bike for a cover without any ports and used a set of clamps to hold the EW-RS910 cover into place while the double-sided tape did its job. (there will be an installation guide on this soon)

Run wires to the other components

Now it's time to install and connect the other components. Again, I used the PRO Internal Routing Tool. Other companies make similar tools, so if you're more a Park Tool or Jagwire person or prefer a piece of string and vacuum, go ahead. Whatever gets the wires through.

First I ran the rear derailleur wire from the SM-JC41 Junction B (in the down tube, next to the bottom bracket) to the derailleur.

Then, a wire from the Junction B to the front derailleur. This wire doesn't go straight up from the bottom bracket, but instead it goes into the down tube and then up.

I connected the front derailleur wire and used a Shimano grommet to tidy up that FD wire hole. Note that I later decided to run the FD wire over the derailleur clamp instead of under - I didn't want to run the risk of the FD wire getting pinched between the derailleur and frame.

After setting up the FD limits there does seem to be a little room to run the wire underneath, so I may go back to that and move it.

Seatpost battery and battery holder

In order to secure the battery in my Deda seatpost I used the Deda seatpost battery holder. Yes, you could use something else like a piece of foam or bubble wrap, or even tape. I generally prefer the official battery holders though.

The Deda system is actually pretty neat. The seatpost battery holder is a single piece and you first slide that over the battery.

Most battery holders I've used slide all the way into the seatpost, sometimes making them hard to remove. Not this one:

Junction B

With the battery connected to the Junction B the Di2 circuit is completed. I wrapped the Junction box in some bubble wrap to prevent it from rattling around in the frame. I then showed it into the downtube where it's hardly visible, even if you know where it is.
(it is also a pain to get out... so make sure the bike works before the tuck away the junction box)

Installing the Power Meter crankset

After installing the BSA Praxis Works bottom bracket it's time to install the power meter magnet. You get this tool that lets you position the magnet. As the tool says, the gap between the tool and the frame should be less than 5mm.

The magnet itself is tucked away in a magnet cover which is then sealed using double-sided tape. I painted the magnet cover red - it comes in black and white, which didn't really match the frame.

A bit of alcohol to clean the frame and then simply stick the magnet cover on. Not sure about that colour for the cover, but for now it'll do. I may paint it dark blue or the right orange next year.

Then insert the crank with the spindle cover attached so that the connector does not get any grease on it.

Now normally you would screw in the preload cap and that's it. This Shimano FC-R9100-P crankset comes with a 'crank installation ring' that is used to set the preload.

You screw this in using the supplied tool and match up the grooves on both so that the connector wire doesn't get pinched.

Attach the connector so the two parts are linked (and have power). You can now push in the stopper plate and tighten the crank arm bolts.

Finally, push the outer cap on and that's it.

Size the Chain and set up the derailleur limits

At this point I like to verify that everything still works, so I determined the chain size using the method described in Shimano's dealer manual and set the rear derailleur adjustment (indexing) and limits.

Then I set the front derailleur up and ran a quick test... everything worked just fine! Success!

I forgot to take photos during this process, but it isn't that exciting anyway. However, if you want to know how to set up your derailleurs just head over to the installation guides.

The guides I used are:

Note that if your front derailleur limits are way off when you try to adjust the rear derailleur it might make more sense to set the front derailleur limits first.

Brake calipers and discs

Disc brakes... yep! I've previously only installed disc brakes on my mountain bike, not on a road bike. Still, the process is similar except for mounting them (flat mount vs post mount). First I installed the discs on the wheels (because.. why not?).

Next up, the front and rear calipers. I'm using a 140mm rotor on the rear so no adapter is needed. You do need to measure the frame thickness and buy the correct length bolts though.

Since I installed new brake hoses, a full bleed of the brake system was required. The dealer manuals state the bike should be vertical when bleeding the rear brake, so I clamped it to the stem and got started.

With the brakes installed and bled it was time to wrap the handlebar tape. I made sure there was some excess wire near the shifter so the wires don't get pulled out when the shifter by accident.

Test ride!

After the build was done it was time for a test ride. This was only a 12km ride, but it was great! If you want to see more of my rides feel free to join the BetterShifting Strava Club.

The tools I used

During the build I used a variety of tools.. Over the years I've collected a bunch of useful and less useful tools - the ones I keep coming back to are listed below:

Questions, comments or suggestions? Things I did wrong? I'm definitely not a real bike mechanic, so feel free to leave your feedback in the comments or send me a message.

BetterShifting Terry

About the Author - BetterShifting Terry

I enjoy playing with bike tech - both bike building and wheel building, bike maintenance and of course, Di2. Besides writing content and working on the technical side of BetterShifting, I also work as a Software Developer in The Netherlands. Read more on the About this site page.

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