Originally Posted by
zacster
The original indexed shifting was horrible. I have a bike with Suntour indexed shifting and it also had a lever to turn it to friction. Not sure if shimano did the same.
Shimano's SIS system also had an option to revert to friction shifting. But the SIS indexing was quite reliable, if you used a full-SIS drivetrain (shifter/derailleur/cluster). The friction option was to appease racers using neutral-support replacement wheels that were not compatible with SIS indexing.
But looking at that cassette it had ramps on it and those would improve the shifts.
The original SIS system did not have those ramps. Those came in with Hyperglide, and Hyperglide sprockets won't install on a SIS/Uniglide cassette without some modification.