I am replacing the 11 speed cassette with a Shimano 12 speed ultegra cassette.(8150). However, the manual is very ambiguous. Which spacer do I need to use? I would imagine using both spacers to get most clearance will cause issues with the front derilauer?
Shimano 11 speed road and 12 speed road cassettes are the same width. So, you shouldn’t normally need any spacer.
Exactly. So people is mainly using the spacers as a remedy to not have cage rub I guess? This would mean having different indexing outside/inside I would imagine.