My Wessex has an 11-32 105 5800 cassette on it, paired with a 50/34. For the type of riding I use my Wessex, I simply don't use the 50-11 combo. Annoyingly, the 11-32 cassette has a 2 tooth jump from 16t to 14t, I spend a lot of time flicking between those two gears and it's REALLY irritating.
With a 50-12 combo at 120 RPM, I'll be doing 40mph. Whereas with my 52-11 (on my Canyon), at the same RPM, I'll be doing 45mph which is great for the type of riding I use my Canyon for.
So I'm looking to switch the 11t cog for a 12t. I've had a look at the manual, as I understand, I'll have to change the 11t for a 12t lockring cog and also change the 13t to a 13t with a built-in spacer (then I'm also adding a 15t sprocket).
All I have to replace are the 12t and 13t sprockets to the appropriate lock ring type, correct?