6800 FC to R 8000 FC upgrade I would like to replace my 6800 FC 52/36 and 6800 FD with the R8000 FD and FC 52/36. I'd like to utilize my existing 6800 brifters, which operate flawlessly.
Are the cable pull on the brifters (6800 vs 8000) identical such that the 0.4 mm difference in chainring spread between the listed chainsets will be dealt with by way of a new 8000 FD?
Yes, all Shimano 11-speed road cable pull is the same.
The long armed 11-speed FDs like FD-5800, 6800 etc can all be and frequently are replaced with the toggle models, i.e. FD-R8000.