Just how freely can I change sprockets on an Ultegra 10-speed cassette?
I have a 11-23 I'd like to
toss out the 11 and 12
get a 12 that goes in position 1
add a 25 on top
Shimano makes this configuration, but rather than buy it, can I just add those two sprockets?
make a 13-25 (again, Shimano makes this configuration) buy getting a 13- tooth 1st position, adding in an 18 and adding a 25 on top?
I guess I'm asking, do all the sprockets come apart, or are some stuck together. If they are stuck together, how can I find which ones are? Is there a set of rules somewhere?