12 Speed Di2 Newbie

54and56

Hi,

Upgraded to a new 105 Di2 equipped bike a few weeks ago and love it all bar the Di2 app / settings. For the life of me I can't figure out how to get the settings to my liking, particularly synchronized shifting which is one of the features which attracted me to Di2. I could bring it back to my LBS but they aren't personally very knowledgeable on the Di2 app (old school LBS) etc so I've watched a gazillion YouTube videos on setting up Di2, but am still unclear and find the Shimao E-Tube app probably the worst and least intuitive app I've used since back in my old Blackberry days!

I'm hoping there are some experienced 12 speed Di2 people here who can help me.

For example. When cycling through the Synchro options by double pressing the button under the rear shifter where one blue light = manual (always a default?) does two flashing blue lights mean the shifter is set to the "S1" options in the app and 3 flashing blue lights means it's set to the "S2" option in the app?

Apologies if this has been done to death before but I've searched and can't find a 12 speed Di2 thread for Neanderthals like myself so starting this one 😓

at1withmyself

There are so many YouTube videos that I would recommend looking there. I found it invaluable when I first got Di2, you should get your answer but also loads more knowledge, hints & tips etc...

mcburns07

Interested to hear what people think here. Have it myself but have been quite happy to just leave it shift like any bike would. Its the smooth and light touch shifting that attracted me

54and56

I literally spent hours watching YouTube videos. Most are either general reviews of the system or they get into technical details of how it mechanically works etc but I've yet to find one which walks through the app and actually explains how to set up synchronized shifting to suit your style of cycling.

If you have found any such videos I'd appreciate you linking to them here.

In particular I'd like to know how to set the shifting pattern so the jump when moving from the small 11 cog in the rear (whilst descending) to the big 34 cog in the rear (as you finish a descent and start another climb) isn't quite so large.

I find moving from the big 34 cog in the rear and 34 small in the front as I top out a climb to the big 50 front and small 11 back as I descend to be smooth but not in reverse as I start to climb. It seems to go from a mid range gear as I begin a climb straight to 34:34 leaving me spinning like crazy and trying to manually move back to say 34:26 in order to maintain a reasonable cadence and keep momentum until the climb gets to a point where i do need the full 34:34.

I really don't want to settle for manual shifting (replicating regular cable shifting) as synchronized shifting is one of the reasons I went for Di2 but if I can't get it to work I'll have to as right now it's just not working for me on the climbs.

Mr. Cats

Better Shifting Terry is vey good on 11 speed so I guess his 12 speed guides should be good too. You can ask him questions directly and he will answer

https://bettershifting.com/12-speed-di2-new-user-guide/#synchroshift

54and56

Thanks @Mr. Cats That looks like a very good resource. Prefect afternoon for a read!!

Edit: That resource @Mr. Cats linked to is the authoritative source for all things Di2.

I finally found something which explains a) how Synchronized Shifting works and b) How to adjust Synchronized Shifting to get smooth / logical transitions up and down the gearing range so the jumps are consistent.

What I found is that the Full Synchro mode set up by my LBS was set up where the auto switch from the 50t to the 34t front chainring when shifting down the gearing resulted in a switch to a gearing ratio that was way lower than the ratio it had just been in and thus I ended up spinning at a massive cadence going nowhere.

The other things the resource confirmed are:-

When you press the function button on the rear mech the if you get one blue LED flash it's in Manual Mode and this is always the 1st default option i.e. the same shifting as your mechanical system.

If you cycle through the function button and the blue LED flashes 2 times you're in S1 mode (whatever you've set that to in the E-Tube app) and if the LED flashes 3 times you're in S2 mode which again is whatever you've set that to be in the E-Tube app.

Multishift is an option that's worth turning on and setting to no limit. It simply means if you press the downshift lever/button and keep it pressed the Di2 system will keep moving down the gear range until you stop pressing the button or until it reaches 34:34 and vice versa going up the gear range until it reaches 50:11.

I found this to be the most informative part of the site ref setting up 12 Speed Di2 Full Synchro Shifting https://bettershifting.com/set-up-di2-synchronized-shifting-using-e-tube-mobile/

JMcL

My personal experience, albeit on 11 speed, is that I didn't go full synchro in the end as I wanted to keep the muscle memory for front shifting on the other bikes. I did try it, but backed out of it.

I've set mine up to shift the rear up/down 2 cogs when the front shifts which is what I'd usually do in manual shifting 11 speed. I also avoid the outer/innermost cogs (just the one) dependent on where the front is to avoid cross chaining.

I did experiment with custom settings, but decided that madness could lie in that direction quite easily, so I think I just picked one of the stock cassettes offered and modified the defaults slightly as above.

With the full synchro I'd set it up to front shift on I think the 2nd last cog and while it did work, I wasn't mad about a front shift happening when not expected sometimes under load. The beep when it's reached the limit I find for triggering the front shift (except in the case when I'm already in the 34 ring and run out of cogs on the back 😅)

barleyman

The Shimano manuals are very clear and easy to follow.

I don't have 12 speed but i was able to customise my 11 speed using the manuals.

7J4MA | Manuals & Technical Documents (shimano.com)

7J4MA | Manuals & Technical Documents (shimano.com)