Is it just me but has anyone else experienced the horrible shifting from the DA Di2 (electronic, not sure if that’s implied in the previous detail). Specifically, I cant stand that the components decide what i gear i should be in an automatically going from one gear ratio to the next, I know how to ride my bike and dont need my components to tell me. The problem is that when it shifts between the big ring to the small while also adjusting into a gear in the cogset, there is a big delay in the gears being solid, I have at least 2 revolutions of my pedal stroke providing zero wattage to the pedals and i lose at least 20 watts, when it does so. I get it that there would be a natural drop in wattage but not only is the wattage way off but any type of momentum that I would want to carry into a climb is lost and MPH drops significantly. Thankfully, i have not attempted to make the gear change while standing as that visual does not look pretty going from high resistance to zero resistance until the chain catches up…I find it hard to believe that shimano was not aware of that. I have tried using the e-tube software and have not found away to the address the front derailleur with a single button. That’s all it would take, rear derailleur is fine as is. I apologize if this has been addressed here already. i just registered for this forum moments ago and was hoping that someone may have a fix for this issue. Thanks
What you are describing is Di2 Synchro Mode. It will automatically shift your FD based on cog position on the RD. This is fully programmable-- you can change which rear cogs trigger a FD shift, and you can set how many RD compensation shifts it also performs.
And, you can turn it off. But, this depends on what version of Di2 you have and the cockpit shift buttons. Shimano’s new time trial standard is single shift buttons which pretty much requires you do Synchro. However, if you have the prior-generation two-button shifters, then you can simply turn it off and be full manual.
One of the little things that makes Synchro a lot better is if you have a Garmin head unit and pair your Di2 to your Garmin. It will beep when your next shift will trigger a FD shift, so you have some warning.
Another thing that may be happening is that your RD shift speed is programmed to be one of the slower options. Mine shifts so fast in the rear that I really do not notice it, and I do even have mine in the fastest shift setting.
Thanks for replying so quickly. I am pretty sure i understand what you are saying. The version i have has 1 button on each aero bar and each bull horn. I get that i can control which gear it does the shift in but the problem and maybe i am missing something is that when it happens simultaneously I have these monster dead spots. I have been told i may have to go back to a previous 2 button version with 2 buttons on the left side on aero bar and bull horn, which is worth it to me but having shelled out a boat load of cash for the Di2 and then have to spend more $ to gain the functionality that seems so basic and a function of a previous version. what i am trying to figure out is how to simply go from big ring to small independent from the rear. I very much know when it is going to automatically switch but it does not prevent the dead pedal revolutions, in lieu of continuing with the same effort before the shift, the only option i have found is to soft pedal, which again burns a match, catching back up to the speed and natural wattage reduction from going to a smaller gear ration and add that up over an Ironman bike length it becomes very material…If I could shift to that gear in the big ring and have it drop to the small ring that would be fine but when it does both its frustratingly problematic. I very well maybe misunderstanding something. BTW, I use the Wahoo element and soon to be Roam perhaps it has similar functionality as your Garmin. Either way I want 100% control of my shifting…Thanks again, I really appreciate your feedback.
one thing common to both syncro (shimano) and sequential (SRAM) shifting is the choice to shift the front derailleur first, followed by the rear. this means you’ll go from a particular gear that’s just a little too hard to pedal to a much easier gear - that’s way too easy - and then the RD shifts down 2 or 3 teeth to the eventual gear you want to be in. i have the same waiting period when it upshifts.
that’s a disadvantage of electronic shifting in THIS mode. i can shift my mechanical system simultaneously, and i can shift my electronic simultaneously as well if i control the FD shifting.
that said, i have grown accustomed to syncro on my tri bike. i would not like it on my road bike. but i’ve gotten used to how it shifts. if you spend enough time with it you’ll anticipate the FD shifts and how to accommodate them with your pedaling. i would encourage you to stick with syncro for awhile longer and see if you can achieve detente with it.
These are your options to go to manual shifting:
Program one of your button sets to control the FD. For example, make your brake buttons shift the FD and your extension buttons shift the RD. This is sub-optimized when you are on the bullhorns, but there is no hardware change and it is still better than mechanical shifting.Switch one set of buttons to dual-button. For example, install convert your bullhorn brake levers to the prior-gen two-button versions. This would give you total manual control in the bullhorns but only RD control on the extensions.Change everything to the prior-gen dual-button controllers.
When I built my bike, I debated which types of shift buttons to put on it and if I wanted to fully commit to Di2 Synchro. In the end, I decided to go with the latest stuff and dedicated Synchro. It does not help you at all, but I absolutely love it and Synchro is one of things about Di2 that makes it great to me on a TT bike. (I would never do Synchro on a road bike where I want total control.)
Another thing that may be happening is that your RD shift speed is programmed to be one of the slower options. Mine shifts so fast in the rear that I really do not notice it, and I do even have mine in the fastest shift setting.
Did you try speeding up the shift speeds? I put all of mine at max speed.
If that is already optimized, see eeeexxxxxxvvviiiii’s thoughts above. You can get what you want with the hardware you have, but you will make some sacrifices.
Got it. Thanks all for the advice. I wish i got on this forum a LONG time ago…this was extremely helpful…Thank you!!