ahultin

I am going to be helping a friend convert his carbon davinci tandem to di2. I have read several of the di2 threads on here and think I have a good direction. The hope is that the di2 will help solve horrible shifting this bike has had since new which would be cheaper than scrapping it altogether. .I have the following parts in my cart and wanted to run it by here to see if we are on the right track. Any help would be appreciated.
Xtr rd-m9050
Xtr rd-m9050
Xtr sc-m9051
Ultegra st-r8050 or st-6870 (bike is caliper brakes but rear is setup to handle disc as well)
Ultegra cn-hg701
CS-hg800 11-34 (hub body is 10spd so has to be 11spd mtn)
Bt dn1101
Sm-btc1 (haven't determined if we can mount internally)
Sm-jc40

Does this look to be the right track?

Joint Venture

You’ll probably need the 13-21-29 chainrings (26-42-58 equivalent) with the conical spacers (they act as shift ramps) from da Vinci to make it work if you don’t have them already. Todd sells his da Vinci tandems with Di2 and has for a few years now, so a quick call or e-mail to him might be advised in order to save some trial and error like which front derailleur mount to use.

ahultin

Yes, i have sent todd at daVinci a message already. He responded to the first question which was could the carbon frame be modified to internal di2. Waiting for reaponse on any other tips and tricks

geoffs

I’d be having a think about just having a double chainring instead of a triple. We’ve just come back from nearly 2 months in Italy using a double chainring setup on davinci canes instead of a triple and the shifting was just fantastic. We’re using Sram etap but you could do the same with di2

DubT

You could just get 2 of these and save time and money. https://www.sportcrafters.com/produc...x-kit-mini-pod

I am using it on our tandem 1 X 10 and am EXTREMELY happy with the arrangement.

ahultin

While that is an intriguing option, I dont think it would save much money. I am right around 1000 so far and that includes going to hydraulic brakes. The take-offs should have a couple hundred in value making it almost even with the 800 the xshifter would run.

act0fgod

If you wouldn't mind posting your progress and results I'd appreciate it. I'm looking at getting a used da vinci and doing the upgrade to Di2.

mtseymour

Do you have a custom length of EW-SD50 cable that is long enough to go from the shifters to the rear bottom bracket? Do your bottom bracket shells have openings to allow the cable to thread through? Make sure that your BB won't interfere with the cable. This is part of the reason why I use the Bushnell Lightweight eccentric without the full shell.

Before you modify the frame, test the setup by temporarily mounting the battery externally. If everything works fine, it's not difficult to drill holes at the headtube, rear BB, and R chainstay. I suggest that you talk to Calfee because they modify all brands of carbon frames, and Di2 conversion is one of their services.

ahultin

I actually had been communicating with todd at davinci and ordered a pinned 28t cog that he said was needed. According to him, because of the aluminium insert in both bottom brackets , most of the wire must go external so i have ordered the sm-btc1 external case for the seatpost battery, this has a six port juntion box. This was all before i found out that this is a calfee built and specced bike with davinci drive and branding. I got in touch with jason at calfee briefly friday so i hope to revisit the internal routing with them. since several of the components were ordered from japan, i have some time lol.

act0fgod

That is the dream tandem.

DubT

Please tell us how you are doing this upgrade for $1,000.

ahultin

Most was purchssed from ebay during the 13% back promotion from last week which resulted in @125 ebay bucks which iwill use to purchase the etube wires
Xtr rd-m9050 289.99 ebay
Xtr fd-m9050 - 69.99 universal cycles clearance from a few months back
Sm-fd905 13.12 ebay
Xt sc-mt800 84.99 ebay
Ultegra st-r785/brs785 245.00 ebay
Ultegra cn-hg701 29.99 local
CS-hg800 11-34 31.66 ebay
Bt dn110 120.11 ebay
Sm-btc1 55.00 ebay
Sm-jc40 19.00 ebaySm-bcr2 89.87 ebay

johnhuebbe

Any update on how it's gone?

act0fgod

From what I have gathered from reading here he is no longer doing it to the calfee/da vinci but instead trying to upgrade a cannondale.

ahultin

That is correct, this tandem is at calfee getting dropout repaired from shipping damage and disc brake strut added then will be sold again. It has already been replaced by a di2 dragonfly as the ips was never optimal for the varying team makeup and had actually been locked out for some time (bike belongs to a blind stoker)

The xtr di2 has found a home on a 2015 cannondale frame i have had hanging in the garage.

poluf

Hello
The front dérailleur doesnt work with chainrings UP to 38 tooth.
Stéphan

ahultin

Though beyond spec, there are many examples on this board of people utilizing this setup with up to a 52t front ring. While I am still waiting for a few items to finish the build, the drivetrain is complete and working well on the stand. I am utilizing 48/36/26 middleburn chain rings.

poluf

OK thank you for the information.

During my editing, the back of the guide touched the 52t when I kept 1/3 mm between the top of the guide and the 52t.

I go to the compact.

ahultin

If you do a search for xtr di2, there is an older thread in this forum that discusses the shim needed to adapt the xtr front derailleur to larger road chainrings. Santana is using this with success as are some other smaller builders