Originally posted by Beth
I ended up opting for replacing my 8 speed 12-26 with a 13-30 spent about $200 instead (had to replace rear derailleur with long cage model)
Any of the 8 speed shimano road RD other than DA were speced for 28 large cog and will shift a 30 and sometimes more. the DA 8 speed was speced for 26 large cog and might not shift a 30. Cage length does not determine ability to shift large cog.It's in the paralleogram. Current 9 speed shimano road 9 speed RD are speced for 27 large cog whether long or short cage, and either will shift a 30. Both short and long cage current shimano mtb RD are speced for the same 34 large cog.