Di2 synchro shifting

[eddief]

I understand the concept. Wondering what real world users have to say about it. Particularly interested in how it smooths things out with 16 tooth difference of compact double. Do you use full or semi synchro and can you describe your impressions? Does it do what you need it to do better than you doing the shifting yourself? Is that possible?

[madsciencenow]

Originally Posted by eddief

I understand the concept. Wondering what real world users have to say about it. Do you use full or semi synchro and can you describe your impressions? Does it do what you need it to do better than you doing the shifting yourself? Is that possible?

+1 one for wondering about the same questions listed above. Anybody using this?

[htwoopup]

I will say that I originally turned the synchro on on my wife's bike. I give her an A for effort in getting into cycling so that we could do it together but she was having a bit of an issue with cross-chaining. So, I thought it would be easier to set up the bike synchro and help her learn the other nuances of an activity that, if you have never done it, has far more things to think about than I realized having cycled for about forever. Things like thinking about traffic and when do I brake took precedence over the big gear goes here when the little gear is there.

One day, I rode her bike a few blocks after I had done some maintenance and I thought the synchro was actually pretty nice.

So, I switched one of my bikes to it. It was weird to get used to at first when the chainring shifts down because of the timing of the front relative to the rear but easy to get used to.

I now have converted all of my bikes.

It is sort of like would you ever go electronic...I was a firm no until I did and now I will never go mechanical again. I don't really foresee going back to "two sided" shifting.

Is it better than I could do without it? That is debatable. I do tend to override it and bump the front up when cresting a hill rather than running through the gears on the way up. So, in a way, it is no different. But whether I am better at shifting multiple gears on the rear while shifting the front or not probably is answered differently every so many shifts. In other words, usually it is probably as good as I do (I doubt that I am better than the machine except in my head) but sometimes it is probably better than I would do on my own.

But, as I said, it is like going electronic in the first place...I would never go back.

And, if it was such a bad idea why did SRAM and Campy copy it?

I have had EPS and my response on the matter with that brand would be the same and probably would be the same on the SRAM AXS version even though I have converted all of my bikes to Di2.

And, remember that if you don't like it you just press the button on the A junction (or use the Etube app if you are wireless Di2) to switch it back to two sided manual shift of front/rear (albeit actuated electronically).

[thermalattorney]

I needed a new Di2 battery around the time Shimano released the upgrade, so I went for it and spent a few months trying out the two modes.

Synchro
Very cool, but felt like a bit of a novelty. The shift points are smartly designed and you can always override it. Unfortunately, I found myself overriding it all the time.

Semi-synchro
I liked this mode a lot, as it automates what one does naturally when shifting the FD. Would've kept using it, except that I do a lot of stop-and-go city riding. It sucks having the RD *always* up shift when dropping into the little ring as one tries to stop. If the majority of your riding is on the open road, I'd highly recommend Semi-synchro mode.

In the end I went back to manual mode. Hope this helps!

[eddief]

this vid is worth a 1000 words. i will try both.

https://www.youtube.com/watch?v=w59EUUbxO1A

[saab2000]

Looks like semi-synchro is a great option. I'm hoping for some Di2 stuff this year for a bike sitting in my basement and I'm definitely curious about these different options.

[rlanger]

I find both modes to be a bit useless, tbh.

When I switch chain rings I always change the rear derailleur first to better manage my cadence. But with syncro, the FD shifts first. So, if you go from big to small for example, your cadence jumps about 20 rpm before the RD shifts. And when you go from small to big, your cadence drops 10 to 20 rpm.

Having said that, I absolutely love Di2 and can never see myself going back to mechanical.

[eddief]

with compact double up front and 16 tooth difference i almost always have to shift the rear one or two cogs after going in either direction on the front. and it think semi does that rear two cog shift automatically. i have been riding triples up till now and one of the reasons to love them is you only use the granny when you need it and don't have to deal with big jumps on the front.

Originally Posted by rlanger

I find both modes to be a bit useless, tbh.

When I switch chain rings I always change the rear derailleur first to better manage my cadence. But with syncro, the FD shifts first. So, if you go from big to small for example, your cadence jumps about 20 rpm before the RD shifts. And when you go from small to big, your cadence drops 10 to 20 rpm.

Having said that, I absolutely love Di2 and can never see myself going back to mechanical.

[rlanger]

Originally Posted by eddief

with compact double up front and 16 tooth difference i almost always have to shift the rear one or two cogs after going in either direction on the front. and it think semi does that rear two cog shift automatically. i have been riding triples up till now and one of the reasons to love them is you only use the granny when you need it and don't have to deal with big jumps on the front.

I'm running 50-34. Yes, semi-syncro does the RD shifting for you, but my point was that it does so slightly after the FD shift. So, if you are riding up a hill with a cadence of 90 for example and then shift into the small chain ring, your cadence will immediately jump to well over 100 at the same power output until the RD shifts down two (or three) smaller rings, unless you significantly reduce power to the pedals.

I just find it extremely annoying and prefer to manually shift the RD first (or even at the same time) as I shift the FD. It makes for a much smoother experience.

[eddief]

not sure, but I heard.

Originally Posted by rlanger

I'm running 50-34. Yes, semi-syncro does the RD shifting for you, but my point was that it does so slightly after the FD shift. So, if you are riding up a hill with a cadence of 90 for example and then shift into the small chain ring, your cadence will immediately jump to well over 100 at the same power output until the RD shifts down two (or three) smaller rings, unless you significantly reduce power to the pedals.

I just find it extremely annoying and prefer to manually shift the RD first (or even at the same time) as I shift the FD. It makes for a much smoother experience.

[Matt92037]

I switched to full synchro just to “try” and never switched back. If spend time customizing the shift points etc, the shifts end up being fairly linear.

I could see if you race or are into fast club rides synchro would not be your best bet.

[rlanger]

Originally Posted by eddief

not sure, but I heard.

Somewhat. But even when it's on the fastest setting I don't find that it does much to mitigate this problem.

[htwoopup]

It is not because the front or the rear goes first per se. It is because it switches when the crank is in a certain position. That is why when you adjust the speed of the shifts it doesn’t affect this phenomenon.

That’s a pretty simplistic explanation but it’s the best I can do on a phone at the moment.

I’ve complained directly to senior management at Shimano about it to no avail. But it still tremendously better than the campy alternative


Sent from my iPhone using Tapatalk

[rlanger]

Originally Posted by htwoopup

It is not because the front or the rear goes first per se. It is because it switches when the crank is in a certain position. That is why when you adjust the speed of the shifts it doesn’t affect this phenomenon.

Sent from my iPhone using Tapatalk

I assume you mean the rear derailleur switches when the crank is in a certain position? Anyway, whatever is happening, the only thing that matters is that the rear derailleur ALWAYS shifts after the front derailleur, which sucks.

[radsmd]

Thinking about using syncro on the gravel bike after putting on the climber shifters. That way I can shift from the bar tops, without worrying about the front derailleur.