CrowSeph

Since my ultegra has the option to combine the shifting with both derailleur i want to compare my experience with other users.

- First try: Semi-Syncro
If the front mech is moved to the bigger cog, the rear will move 2 gears upward.
If the front mech is moved to the smallest cog, the rear will move 2 gears downward.

This feels awsome as first impression but after a while the sensation became the opposite.
2 gear shifting is awsome to keep the cadence but sometimes you need a drastic change , slowing or increasing the cadence rate.

- Second try: Semi-Syncro
If the front mech is moved to the bigger cog, the rear will move 1 gears upward.
If the front mech is moved to the smallest cog, the rear will move 1 gears downward.

This feels quite different, is not drastic as the 2x shifting but you still keep the semi-syncro and the cadence different.

The Syncro mode seems also interesting but honestly i never tried because sometime during small climbs i still keep my 52 front with any of 21-24-27 cogs at the rear (i know, that's is wrong but for a small amount of time is not a problem). In those smal climbs a syncro mode will slow a bit since the shifting is not superfast, it is also not very slow but when i swap front chainring i usually have the tendency to increase the cadence speed, otherwise i can feel the trasmission suffering (also somewere i read that type of shifting require high cadence). Basically even is the syncro must be the optimal setup in the paper, during the real riding seems not that effective.

- Possible combination between semi-syncro 1+2
During ride i noticed that: If i move the front mech from high to low i must have a small cadence variation but viceversa from low to high on the front mech i should keep the almos the same cadence but with the difference of the force needed.
So, if the front mech is moving high to low , the rear should move one gear down.
But if the front mech is moving low to high the rear should move 2x gear up.

What you guys thinks?
And if you have any electonic drivetrain, would you please share your setup?
Also sram uses a different names but we still understand

rm -rf

My 6850 Di2 didn't have any syncro option when it was new. I don't have any need for it now.

Like you, I like controlling my own front derailleur. Sometimes cross chaining is fine for a few pedal strokes. Or I'm coasting uphill from a fast downhill just before, and only want to shift the front, leaving the cassette where it is.

I have the setting "shift 3 cogs with a long press" ( of 1/2 second or longer).
At the base of a sharp climb, holding the two bottom buttons shifts to the small chainring and three harder gears on the cassette.
Rolling over the top of the hill, holding the two top buttons shift to the big ring and three easier gears on the cassette.
No thinking needed!

Steve B.

Never use it. Mostly as for where I live (flat Long Island, NY) I can sit in my 14-28 cassette and on the 50 ring, most of the day. On rare occasion I might have a hill that would see me go down to the 34 chainring. Otherwise I am in the 50 all the time so rarely shift the front, thus have no need for Synchro.

roadie276

I liked the idea of the synchronized shifting in principle, but after trying both a bit, I decided it was easy enough to shift myself, as I sometimes don't want the automatic shift, and shifting's so fast when it's electronic that it wasn't a big deal.

I did make one other pretty unconventional change to my Di2 setup: I changed the shifters from being derailleur-oriented to being shift direction-oriented. So the right lower shifter is still +1 gear in the rear, but the upper right shifter shifts up the FRONT derailleur. And on the left the lower shifter downshifts the rear derailleur, and the upper left downshifts the front derailleur. I did this initially because my right hand was getting tired from shifting (I shift a fair amount on the rolling terrain around here, and as a person who's on computers a lot, want to avoid any extra opportunities for repetitive stress on the hands), because it let me get my left hand in on the shifting more, since most of my shifts are on the rear. Anyway, this was an impossibility with mechanical shifters, for obvious reasons, but is trivial to set up with Di2, and I actually like the setup now that I'm used to it. I have no idea if anyone besides me would ever find this useful/think this is sane.

Koyote

I use it in full manual with the right (rear) shifter set to keep shifting as long as I am pressing the lever. I find synchro and semi-synchro too clunky.

tempocyclist

I use "full manual" mode on my road bike. I didn't like the syncro or the auto-changing of the cassette. I'm sure some people love it though.

On my TT bike the only option is full-syncro. I was sceptical at first, but it's fine as I tend to spend most of the time in the big ring and you get to know at what point it's going to auto change up/down on the front.

CrowSeph

thanks guys for sharing your opinion

Iride01 

I have used the full synchro mode for all but the first four maybe six months of the three years I've had Di2. And the only gripe I have about it is that sometimes front shifts from large to small ring mess up my cadence when I'm trying to accelerate while climbing a hill. My cable pulled 105 5800 handled that much better. The issue seems to be that the rear shift just isn't quick enough when that front shift happens.

I've somewhat mitigated that by telling Di2 to downshift to the smaller ring when I am in the 3rd largest rear cog (by tooth count) and call for a shift to a lower ratio (press the big button). You also have to change what gear the rear is shifted too also or else the ratio steps won't be proper. This seems to get me already in the small front before shift to the small ring will be a detriment to my cadence.

One benefit might be that my chain seems to be lasting for a long time since the full synchro never puts me in a cross chained situation. But well have to see how far beyond 5000 miles it goes before I really start to say it makes a difference.

Camilo

My Sram AXS bike has the same sort of settings: Compensation (where the rear moves automatically when the front is changed) and Sequential (where the front shifts automatically depending on where the rear shifting is and the rear also compensates for the front shift that occured).

Ive tried both and don't like either. Neither can take into consideration what the terrain is actually like when you're shifting and other factors like, have I shifted too late, etc. Having actual control over both front and rear results in fewer jolting shifts or shifts that have to be compensated for because they're just not right for the situation you're in.

They're interesting ideas though, especially Sequential. For someone to just have an upshift and downshift buttons and not think about FD might be valuable to some. But the wide range 1X systems have overcome that for the most part with reasonable range of gears.

PeteHski

I tried using the "Compensation" mode for a little while (with both double and single rear shift comp), but I found the rear shift caught me out a few times at the start of a climb when I would shift down the front and stomp on it before the rear had finished its compensation shift, resulting in a bit of unnecessary crunching. So I went back to manual mode. Never tried sequential as I want full control over front shifting. This is on a Force AXS group btw.

jaxgtr

I tried it and decided I hated it. Just stayed with me controlling the FD. I also reside in the land of the flat, so not like I am shifting the FD that much anyway.

CrowSeph

After a while i removed the semi-syncro mode.
It's strange because now i can feel the drive train shifting faster but also sometimes when the cadence is not that extreme the difference whitout is very noticeable.
I'll keep in this way and then i'll post my personal thoughs