Sergio_CH

Hi, All

I had my bike set up by mechanic yesterday. RD hanger was bent, and they adjusted RD as well.
I went into E-Tube software afterwards and saw that RD adjustment setting is +4, while before it was 0, so I assume mechanics used E-Tube software as well (unless adjusting screws on RD changes settings that one sees in E-Tube?).

Anyway, I went then to shift mode setting and saw that I had 53-39 on FC instead of 50-34 which I actually have on my bike. The CS range was set correctly to 11-32.

Now, I do not know if mechanics set it like that or if it was set from factory, but I now reset the front to 50-34 and I had to go through the following screens where one sets Shift Mode 1 and 2.
I used whatever was in those screens (I guess defaults).
I have shift mode 1 set to semi and shift mode 2 set to synchro.
Synchro shift interval is set to Normal.

Once confirmed, I see that Gear Position Control is grayed out. I cannot change it but it seems to be Set.

I read the E-Tube manual and I find it very lacking and not clear for a layman like me. I have questions.

1. Gear Position Control. Why can I not set it anymore? Does it still work or will I have chain popping off if I shift RD one too much (given that semi-synchro set to more than 1 rear sprocket)?

2. What is Synchronized Shift Interval? What is the difference between Normal, Slow and Very-Slow? Why would I ever want it set to slow or very-slow?

3. What does it mean to have two shift modes, Shift Mode 1 and Shift Mode 2?

4. Why can one set both SM1 and SM2 to the same shift mode (say, synchronized)?

5. Does the order of shift modes matter? That is, why would I sent SM1 to semi and SM2 to synchro, and not the other way around?

I am trying to get my head around this stuff and Shimano does not make it easy.

Thank you in advance for your help!

Steve B.

Shimano Di2 plays nanny state with the Di2 system in many respects. As example, they only let you set a configuration of crank or cassettes based on what they currently sell for these systems. They used to sell an 11 spd. 11-23 cassette as example, but as they no longer sell it (even if you own one) they don't allow that cassette to be used in the Di2 setup. Likewise if you were to buy an FSA 46/30 crank, you cannot enter that crank choice into the system as Shimano doesn't sell it. Big PITA in most users opinions.

They also "protect" the system in many respects and lock out certain gear choices if using Synchro or Semi. They assume you'll make what they think is a bad choice and use the smallest chainring and the smallest cog, so they lock out that selection in the system if you tell it you are using a particular crank and particular cassette. Thus a 50/34 crank with about any cassette will have the system prevent a shift to either of the 2 smallest cogs while in the smallest chainring.

You can cheat the system and tell E-Tube that you have a 53/39 crank and 12-25 cassette (when you really have a 50/34 and 11-25), the system will then let you use all the range of the cassette small/small combo's, etc... when in manual mode. The reality is you can tell E-Tube you have that crank and cassette of type A then install Type B or anything you like, it's not going to be counting the number of teeth on a ring or cog. Cheating lets you use manual mode to move across the entire cassette range typically when in manual mode. You can then and usually set the Gear Position control to Off, which releases control. About the only time not using the system you tell E-Tube is if you are using either the new bar display unit or you have Di2 connected to a Garmin where you see the gear selections on a screen. Than what you've displayed will be wrong.

When you enable Synchro or Semi, you are releasing shift control to the system. Semi will only move the rear to different gears IF you change rings up front. Full Synchro changes the front and rear IF you hit certain combo's. When you tell E-Tube the actual crank/cassette combo and define a shift map, the system figures out when the next appropriate gear is and shifts front and/or rear to get to that next gear. Your call as to whether you like or want that.

Fast/medium/slow only defines the speed the system moves during these shifts but does affect how the system responds when you do a press and hold of the buttons. Again, YMMV and you need to try different settings and find for yourself what you like.

EDIT:, And for question 3 and as far as I can see, there's no "SM1" or "SM2". Shimano shows it as "S1", "S2", or "M" for Shift modes 1 (Full Synchro), 2 (Semi) or Manual. Where are you seeing "set both SM1 and SM2 to the same shift mode (say, synchronized):.

And you are correct that the manual sucks. They do not well describe WHY you have these selections or the logic for them which makes it hard to then select one over the other.

Sergio_CH

Thanks, Steve
I got if figured out in the end.
I can change shift modes with the button on my Junction A.
I am also pretty content with the way Shimano sets the gear choices for my crank, I am not climbing large mountains with my road bike, I have mountain bike for that. :-)

August West

On the Garmin, at least my 830, you can switch between Auto and Manual setting for the front and rear derailleur gear selection displays. In manual you are able to set the chainrings and cogs to whatever you are running so even if you lie to E-tube the Garmin will read correctly as long as you enter the correct numbers. The gear display has turned into one of my favorite features.

And I agree the E-tube directions from Shimano are lousy. After trying to find something of value online I finally just went out the garage, set a stool next my bike, sat down and started playing with the E-tube app on my phone. It took a bit of time but once I figured it out it isn't too bad but there is no reason a company like Shimano couldn't put together a little tutorial to make it less daunting in the beginning.

Steve B.

My experience was when trying to run a 50/34 crank with 11-23 cassette, I’d cheat and tell E-Tube I had a 53/39 and 12-25 cassette which then allowed Gear Position to be off. That then let me use every cog in the small ring. BUT the Garmin picked up on what I had told E-Tube was the “fake” configuration. There’s a method to manually “tell” the Garmin what gears you are using, but it wouldn’t stick. Every time I turned off the Garmin and re started, the E-Tube settings, with there incorrect crank and cassette, would show up. This was 2 years ago, I had since moved to a 14-28 cassette, wasn’t using small/small, so am fine with it, with the Garmin displaying correctly. Possibly it works differently now, never wanted to futz with it as it works fine otherwise.

August West

Sounds like a Garmin bug (go figure) that got fixed since then. Out of curiosity I just tried mine, setting E-tube to a bogus 53/39 turning off Gear Position and confirmed it would let me shift to the smallest cogs. Left the the cassette at 11-32 which is correct. Then set the Garmin to manual mode with 50/34 chainrings which I have and 11-32. I restarted the Garmin and it read out the correct 50/34 manual chainring setting. I always just use Auto since the Gear Position doesn't really bother me and I would never intentionally ride those combos anyway. But I should really just use the Garmin manual manual setting since I change cassettes often. It is a lot faster just to change the 830 than going into the E-tube app and changing it there since I never use Synchronous or Semi-synchronous so it doesn't matter what the E-tube is set to.