Originally Posted by
bruce19
I've posted this in Road Cycling but have gotten few responses.
This sort of inquiry does best in the "Mechanics" sub-forum if one can past the guff of some who post there.
Here's how, but it takes two 10 spd Shimano cassettes, a CS6600 "Junior" & a 5700.
13-14-15-16-17-18-19-21-23-25
12-13-14-15-16-17-19-21-24-27
Use the "bottom" 3-cog 21-24-27 on the Junior cassette which was designed to shift to a 21 8th position anyway.
Use the lockring from the CS6600, custom 13-27 Done. SRAM/Shimano are compatible.
edit: And you get a 12-25 as a bonus!
-Bandera