Originally Posted by ColonelJLloyd

No, you're right. They'll handle it easily. I thought the OP was after a Shimano RD specifically, though. In which case, a GT200/LeTour/Crane long cage will shift it, but that's not where my head was when I initially read the post.



You actually might not. I would imagine any of the MTB derailleurs will shift a 34t cog. You need a long cage for chain wrap and we don't know your requirements in that regard because you didn't mention what your chainrings your crankset has installed.