Originally Posted by
ThermionicScott
Long cage derailleurs came a long way between the 70's and 90's. My circa-1990 Deore LX shifted quickly and flawlessly despite having a long cage. I would rather have as much capacity as I could possibly need, than to get clever with a short-cage derailleur and hope I don't absent-mindedly destroy it while out on the road.
I would say even within the 70's... The difference between my previous bike with a Suntour GT (long cage, but heavy steel and low end) and my current bikes with first-gen Cyclone GT and Blue Line GT are night and day. The Cyclone and Blue Line still represent some of the best friction shifting available, I would imagine, especially when coupled to modern ramped rear cassettes and freewheels. When compared to my other bike with a Microshift Centos short cage in friction mode, I could not perceive a difference.