sturvey

Heh. So, a bit more limited than I had hoped. I have 50-34 and 11-32 and I can only move the downshift down gears, not up. What I mean is, the software currently has the shift from the brig ring to the small ring happening when I get to the 2nd largest cog (28). I'd like it to downshift to the small ring when I hit the 3rd cog (25). No can do. I'm going to try lying" to the software about my gear combos to see if it opens up

oldacura

For some reason (known only to Shimano?) the current software will only allow a shift from the big ring to the small when the rear is in Gear #2 (2nd to biggest cog). I too would like to have it shift from big ring to small ring when the cassette is on Gear #3. Maybe this will be changed on future releases.

I do like synchro shift. I have not yet tried semi-synchro. I like that the display beeps (twice) when one reaches the rear cog right before it wants to shift the front derailleur. It warns you that your next shift in the sequence will involve the front.

mtseymour

This issue has already been discussed (see post #73). "Lying" to the software won't work. However, the full synchro mode still allows the left shifter to control the front derailleur at any time.

oldacura

Getting more miles on with synchronized shifting - and liking it more. The one shift that I do not like is when the front drops from the big ring to the small and the rear compensates by shifting two smaller cogs. There is a lag while the chain is not engaged on the rear cassette. This is maybe 1/2 second but noticeable. Anyone else notice this? Any fix for it?

Marcus_Ti

I think the lag could be fixed by a future update, if Shimano let it.

IIRC the synchro shifting options have a speed field in the E-Tube software config, but that field is limited to "normal" and slower and really-slow. Whereas normal shifting can be set to other speeds like "fast" and "very fast".

Just like how based on crankset your options for multi-shift are variously limited rather arbitrarily. Why should a 50/34 be able to shift 3 gears in synchro, but a 52/36 only do 1?

oldacura

The more I use Synchro Shift, the more I like it. I'm still not convinced that it is enough to justify going from mechanical to electronic shifting but it is pretty neat. In fact, I can't see why anyone who has Di2 wouldn't use it. I have not yet tried semi-synchro but I can't see what the advantages would be.

Is there anyone here who had downloaded the synchro-shift software and tried it out reverted to "manual" shifting? If so, why wouldn't you use the synchro?

fronesis

I did.

I just wasn't comfortable with the way synchro-shift conducts the shift from the big to the small ring - mainly because of the timing between moving the FD and then correcting in the rear. I'm a very high cadence rider and I climb a lot. If I'm moving up a long hill that is gradually getting steeper, I will shift down repeatedly one gear at a time in order to maintain my spin. When I get to the shift that drops the big chain ring it leaves the RD where it is and moves the FD first; I'm already at such a high cadence that dropping the front ring gives me way too low a gear prior to the correction in the back, but the correction takes too long so I lose momentum (not to mention looking like a cartoon character as my cadence shoots up to 150rpm!).

Shifting manually I will always adjust the RD first (1 or 2 quick shifts up) before dropping the front ring.

The upshift on synchro-shift works beautifully precisely because it moves you first to a gear that is too big, and then adjusts. I wish they'd do that for both shifts: first go to too big a gear, and then adjust to where you want to be. This would require that the upshift move the FD first and the downshift move the RD first. No idea what other variables this might bring into play.

Anyway, long answer, but I have a bike with syncrho-shift. I played around with it a lot and think it's a cool idea. But I ride in manual mode now.

For the record: I'm not on a tandem (I came here because this thread has such great info in it!).

oldacura

Shifting on a tandem is more complicated. You cannot just decide to shift, ease up a bit on the pedals, shift & then back on with the power. It helps the bike (and the stoker) that both riders anticipate the shift. The synchro-shift off the big ring is the most problematic. I have found that if I announce "downshift", the stoker knows what is going to happen and eases up a bit. The shift is still a bit slow but the stoker and the bike both appreciate the coordination.

We are getting better as we get used to the shifting.

twocicle

For those cases where you want to downshift the FD and control the RD too, there is nothing to prevent you from overriding the mapping doing so manually, even when semi-synchro (same functionality as the mtb derailleur synchro) is enabled. I do this all the time on the tandem when I anticipate a FD shift will be needed at a crucial point where no power during an auto/synchro shift would be less than ideal. This combo of using synchro and overriding becomes very second nature after a little usage experience. I have found synchro especially nice in combination with a triple chainring, mostly due to the complexity of remembering where the optimal crossovers (front and rear combos) and the difficulty of quickly managing those changes on a tandem - even with the Di2 display as a bonus.

As something of an analogy, synchro is like having an automatic transmission for driving around town and in traffic. Then whenever you want to hit the manual override - it's there instantly.

fronesis

Interesting.

But I'm not sure I follow you. If I have synchro shift enabled (whether semi or full) then when I move the FD, the RD is going to adjust – 1 to 3 cogs, depending on setting. Shifting manually, I'll usually move the RD down the cassette 1 or 2 cogs before dropping from the big to small chain ring. Now, you're right: if I have synchro shift enabled, I can still anticipate a FD downshift and move the RD manually, but then when I do make the FD shift, it will *also* automatically move the RD 1 to 3 more cogs. The end result is that I will be in too big a gear when I'm done (the 1 to 2 cogs I shifted manually to anticipate the FD crop, plus the 1 to 3 cogs moved by synchro shift).

I suppose I could set the synchro setting to adjust only 1 in the back, and then experiment a bit more with it. I'm sure I could get more accustomed to it.

Still, I wish there were a way for the syncho mechanism for the FD downshift to function by moving the RD first.

oldacura

I spoke to Rob at Calfee regarding my issue with full synchro shift (the jump from the big ring to the small is too big).

He suggested that I try semi-synchro.

With full synchro, I shift the rear (right) shifter up or down. At pre-selected changes, the front will jump up or down with a compensating move of the rear.

As I understand it with semi-synchro, one shifts the left shifter up or down. This moves the rear derailleur up or down until with either 1, 2 or 3 gears, the front will move to the big or small ring. As I write this, I don't think that I understand semi-synchro.

Has anyone here used both? If so, which do you prefer and why?

Marcus_Ti

Full "synchronized shifting"...you don't need (although can still have) FD controls at all, as your FD moves at predetermined points. FD is on auto-pilot

"Semi-synchronized"...You shift the FD yourself, just like RD.


Both can use a multi-shift with the RD to compensate for the gear drop-and get a gradual gearing progression. Which you like more depends on your terrain and gearing. More punchy/roller terrain, you'll probably like semi more, least IMHO.

oldacura

So - with semi I do small shifts with the rear and the front never moves on its own. However, when I do shift the front, the rear automatically makes a compensating shift of either 1, 2 or 3 cogs (depending on how I pre-select). Do I have this correct?

Also, with full synchro, I can program it to prevent cross-chaining. It sounds like semi has no similar provision. Right?

Marcus_Ti

Correct on both counts.

Di2 is quite customizable...so much so that lots of its tweaks aren't well documented. It ofc doesn't help that the terminology Shimano uses is rather opaque, at least in English.

Peaknik

My new bike comes with Ultegra 6800 Di2, I've read that it is possible to get the synchro functions just by upgrading the battery. According to Shimano (sorry, can't post links yet) you just need a BT-DN110 battery AND compatible front (FD-6870/FD-9070/FD-9150) or rear derailleurs (RD-6870/RD-9070/RD-9150), are those front and rear derailleurs coming with Ultegra 6800 Di2? (also I can't check it by myself because I still don't have the bike).

mtseymour

We also prefer that the synchro shift happen sooner (ie. drop into small ring before the 2nd largest cog). We tried "lying" to the software without success. We still like using full synchro, and just manually downshift into the small ring when we approach an abrupt, steep section.

I think that most Di2 users are aggressive riders (or racers), and prefer to stay in the big ring for as long as possible. A quick response is handy in a paceline because getting dropped means a lot of work to catch up.

Peaknik

Answering to myself: I just came from the store and it seems I will get a free of charge upgrade from Ultegra 6800 to 6870, in any case, I have made my case that I need the new battery!

Peaknik

Got my bike finally, but with a Ultegra R8000 and Dura Ace disks, looking forward to dive into the settings!

mtseymour

Did you get the Shimano MT800 display? This replaces the Junction A and shows bettery level, gear position, and synchro mode.

Peaknik

No, I plan to use my Garmin Edge for this.

oldacura

Haven't been following Di2 developments lately but we've been riding our Di2 tandem.

Also, I haven't updated our software for some time. Have there been any new software features on newer software releases?

mtseymour

I'm not aware of any new features on the latest E-Tube software. However, Shimano continues to offer firmware updates for new shifters, derailleurs (eg. RD-9150), and other Di2 (eg. optional switches). When you load the E-Tube app on your iPad and connect your bike, it should tell you if there's an available upgrade for your Di2 components.

ggoo888

Was this ever addressed? I still cannot set it to change earlier than the last two cogs when going from 50 to 53. It's strange that I can make a preset, but then it has a exclamation point said it is out of range. Why would that allow you to create one out of range, but not use it.