9 to 11 speed partial groupset upgrade? Is it possible? I have a Shimano Sora 3500 full groupset (FD 50-34, Crankset 170mm length with BB RS500 (BC1.37 x 24), Sprocket 12-28) on my road bike. 

I want to make a partial upgrade to 105 set due to my budget limit, by:


changing both shifters to 105 R7000;
changing the rear derailleur to 105 R7000 GS (long cage);
changing the cassette to Shimano 105 CS HG700, 11-34T (fortunately my wheelset can accommodate the 11 speed cassette);
using Shimano 105 SLX CN-HG601 11 speed chain; and
still keeping the current installed Sora 3500 FD, crankset, and rim brakes.


Please kindly share your thought whether is it possible or I need to go with a full group upgrade? 

I believe the Sora's crankset and front derailleur should be fine, right?

Thank you.
The Sora front derailleur is not compatible with the front 105 shifter. Shimano changed the actuation ratio (ratio of cable pulled to cage movement) on 11 speed road groups. 

The Sora crank is not compatible with a narrower 11 speed chain. The chainring spacing is optimized for a wider 9 speed chain.

YOu can look up Shimano component compatibility on their product information page.