I upgraded both my gravel and road bikes to Ultegra 12 speed di2. The rear shifting is great but I cannot figure out the front shifting. Both have the same problem, when I setup the front derailleur with Shimano / better shifting instructions I doesn’t want to shift to the big ring. It shifts barely when I soft pedal. I’ve done the setup many times really trying to get the gaps right.
I have to adjust the limit in the app so there is more gap in the big/big and big/small than in instructions so it shifts better. Problem is it then sometimes drops the chain over the big chainring.
And it still doesn’t grab the front chainring like with 11s di2 or the Grx mechanical on my gravel bike, they were flawless.
I’ve setup the front derailleurs as straight as I can see and the height should be good. The road bike has Ultegra 12s rings and the gravel bike has 11s GRX rings both almost new. Both bikes have new Ultegra 12s chains. The support screws are tightened enough. Gravel bike has 46mm chainline but the adjustment in the app is barely enough to make up for it.
I’m obviously doing something wrong but can’t figure out what. Do I just have to manually figure out the correct high limit to balance shifting / chain drops? Any ideas why this is happening?