Di2 on S40

[Greg S]

I've tried searching but the search terms I've used either match e-bikes (search for "battery", "electronic") or are too short ("Di2") so if someone can point me to an existing thread that'd be great.

If not, has anyone set their S40 with Di2? If so, lots of questions:

• Did you use road or mtb components or a mix of the two?
• Road shifters or mtb shifters?
• Where did you put the battery?
• Any wiring tips or gotchas?
• What size cassette and crankset are you running?
• Any issues with the brakes (mechanical disc) and the shifters you used?

My S40 is set up with a Dura Ace compact 50x34 crankset and an 11x40 cassette which puts it well out of the range of the road Di2 spec although I have used this combination successfully on a road bike (GS rear derailleur).

I'm thinking that I'd need to use the mtb front and rear derailleur in order to get the capacity I want and it's my understanding that those will work with road shifters. I'm not opposed to mtb shifters if that'd work better.

Advice appreciated and links to threads welcome.

And before anyone asks, I've got carpal tunnel in both hands. I'm able to shift (SRAM gripshift) OK but this gets harder on longer rides. Since Di2 is "push a button" I think it'd be easier on my hands.

 

[Mathew Fy]

Try here:
https://forum.cruzbike.com/threads/what-would-you-do.12850/
I recall someone posting somewhere a printed battery holder that fit inside the slider.

 

[GetBent]

Hi,

I have a V20, but I think it is similar enough to the S40 that this info will be of some use to you.

My drive train set up: FSA SL-K Light Adventure Modular BB386EVO crank set (46/30T) paired with Shimano DI2 (RD-6870-GS and FD 6870-F). A WickWerks Fit Link is needed for the size chain ring that I used. This set up might not get you the range you want. I can use 21 of the 22 gears. The only one that does not work is "large" - "large". It actually does work, but it makes a lot of noise. Using synchroshift prevents the use of that gear combination. I am also using the Di2 MT800 instead of the "A" Junction box. This has a lot of advantages: Better battery status display, multiple shift modes, and it displays which gear I am in. I also had hand and other issues which caused me to move to a recumbent. The MT800 allows me to use what is called "Synchroshift" mode. This will automatically double shift for me. For example, when I am in my top gear on the rear cassette, and up shift again, I have it set to shift to the large chain ring, and downshift to 8th gear on the rear cassette. I can also remap the way the shifters work. So I set mine up so that the upper button upshifts, and the lower button down shifts. I did that on both brifters, it just makes life easier for me. Using syschroshift, I never need to use the left shifter.

The battery is in the steering tube. I put in a piece of pipe insulation. It fits well, no problems. Be careful which battery you get. Only the newer battery has the brains that allow for the use of some of the advanced functions, such as synchroshift.

I put an external "B" junction box on the bracket that holds the FD. There is a threaded hole there which is perfect for mounting it. The point of that, is so that if I need to disassemble the front end of the bike, all I need to do with the wiring is disconnect it from the junction box. Keep in mind that hiding the wiring through the tubes requires drilling a couple of small holes.

I used Shimano caliper brakes. They worked well until I switched to a smaller chain stay, then I kept bashing the inside of my right leg on the brake. The problem was solved by getting an (absurdly expensive) Omega X.

More detailed info is on my post beginning towards the middle of page 2.

 

[Greg S]

Thanks @Mathew Fy and @GetBent very helpful!

I'm very familiar with Di2 (have it on two DF bikes) so I know about the various shift modes. @GetBent what size cassette are you using? Being able to do big/big is definitely a function of chain stay length and getting the chain length exactly right. One of my Di2 bikes will do it OK, the other will do it but with lots of noise. At any rate, it's not a combination I ever use anyway and the built in protection that the Di2 shift modes provide helps a lot. On a bike (DF) that's exactly like the one with Di2 with mechanical Ultegra I inadvertently shifted onto big/big with a chain that was one link too short and blew up the derailleur.

And @GetBent you refer to "more info on page 2", is that in the thread @Mathew Fy posted or another one? I don't see a link in your post.

Thanks again to both of you for the info!

 

[GetBent]

I am using an 11/32 cassette.

https://forum.cruzbike.com/threads/getting-off-the-fence.11254/ Start at about the middle of page 2. Keep in mind that this is the first bike that I have built. There are a couple of build diaries on this forum which I found to be very helpful.

Cutting and splicing the wire that I fished through the chain stay was a pain. Fishing it was easy. The wire was so thin, that none of my wire strippers would work. Once I finally got the insulation off, the wires were difficult to work with because they were so fine. When I switched chain stays, I used a larger hole about 1.5 inches forward of the drain hole, on the inside of the chain stay (the wheel side) centered between the top and bottom. That was done to avoid cutting and splicing. Just used a stock cable.