Originally Posted by
alcjphil
Like you, I am a little perplexed by Shimano's decision to separate cable pull ratios on road and mountain bike derailleurs. Of course it makes no difference to someone riding only road bikes or only mountain bikes, but for people doing something in between, such as touring, it really complicates things. I predict that "9 speed" mountain bike rear derailleurs will become highly sought after items if Shimano ever discontinues production. I am using one on my touring bike currently and I am wondering if I should stockpile another, just in case. I know that Shimano had to change pull ratio in order to advance to 10 speed mountain bike shifting and to 11 speed road shifting, but in a company as big as Shimano I wonder if it was a case of the two hands not talking to each other
Shimano also switched to the Suntour/SRAM single pivot design with their Shadow stuff (now on the new DA too) which means there is now a "minimum largest sprocket" in the specifications. On most 10 speed MTB RDs this is 36T, and on 11 speed MTB RDs this is 40T I think. There is the short cage ZEE RD for example, there is a version for 28T and a version for 36T.
I'm not an engineer but I think since the derailleur does not rotate on the upper pivot it can't follow the rise of every cassette. I've seen that if you mix up the ZEE derailleurs and use the 28T spec on a 36T cassette the chain will be completely slack.
This might limit usability on road bikes too if you use 28-32T cassettes.
Personally I would just love to run a clutch RD on my road bike natively without an adapter (or I should switch to SRAM). The roads here are so bad that sometimes my bike sounds like it's going to fall apart beucase of the chain constantly hitting the chainstay.
I've built up a hybrid fitness, road bike with straight handlebars and a clutch RD and holy crap it's like magic. I absolutely love it. Complete silence even on the worst roads.