custom shimano groupset

[Guilherme_]

Maybe some thoughts about the front derailleur.

I have di2 2x11 Ultegra,  Di2 2x12 Ultegra and Di2 2x12 105

The 105 front derailleur is basically the derailleur from the 2x11. It works the same way, it is set up the same way. It is slightly slower than the 2x12 Ultegra derailleur, that's absolutely correct.

Unless you don't have both you won't even mention.
And another thought: there are some reports about very early mechanic failures (around 2 years of use)in the 2x12 Ultegra / DuraAce derailleur. 
The 2x11 seems to be more robust. The downsizing probably comes with a prize
From my side, the  Di2 105 is the best value for money if you want to use Shimano electronic shift.  If you can live without the extra buttons and the missing option of tria shifters.... there's nothing missing in the package. Functionality is amazing good.

I think i will go for 105 then, i am not looking for the best, I just want to know where in the 105 the upgrade does really a difference you know?

[Pedaldancer]

I think i will go for 105 then, i am not looking for the best, I just want to know where in the 105 the upgrade does really a difference you know?

So... there are 2 Di2 105 in my equipment...
I exchanged the chainrings on one bike- i compared all single parts of the crankset and the only reason why the 105 crank is more heavy than the ultegra is the large chainring.

I bought nice Ryet.. they haven't been that cheap , yes.  But the bike was delivered with 52/36 , which I wanted to exchange anyway to 50/34.
On my daily commuter Gravel I bought a groupset and exchanged from 2x11 Ultegra to the 105 Di2 ... I didn't even mount the crankset as I wanted to keep the FSA 46/30 supercompact.
Other than that I was also riding a 2x11 105 crankset ... there's nothing bad to say. Only again: the Ultegra and DuraAce cranksets from that production time may be faulty due to glueing process, the 105 is not affected (forged which is slightly heavier)
  If the weight adder doesn't scare you,I wouldn't exchange parts, at some point it is really cheaper then to go directly with ultegra.  However for some people the 105 is kind of a "mental issue" .... so in their eyes I downgraded my commuter from Ultegra (mechanic) to the Di2 105... honestly.. this was a massive upgrade, I just repeated what some people think.

[hubba]

Can you send me the link please?

He will mark the value low if you ask for less taxes. With a 50€ coupon it should end up about 850e now. Of course 105 on Aliexpress is even cheaper, but don't expect great warranty support.
https://www.aliexpress.com/item/1005006240207117.html