Originally Posted by
RiddleOfSteel
Wondering aloud here, but I wonder if Shimano employed the same RD cable pull ratio as Suntour when they (Shimano) introduced their SIS groups. From 6-speed on, it's been a ratio of 1.7 for them. Or perhaps it was everybody copying everybody and the "origin" of that ratio is lost, as far as who did it first. I just think if SIS 7s shifter + SIS-capable RD + 7s cassette/freewheel = works well, and for me SIS 7s shifter + Superbe Tech RD + 7s cassette/freewheel = works well, and for a few of you getting a Vx RD to work with an SIS/Accushift shifter, something's gotta be the same across those companies. Maybe Shimano saw that ratio and thought 'conquest' -- use that ratio for their RDs, but in case things went belly up for Suntour and their shifters couldn't help deliver good shifting, then Shimano would swoop in with reliable DT shifters that could work with current and older Suntour RDs.
I want to start a thread of unofficial unexpected and experimented indexed shifter+derailleur combos. It would include brifters as well. Jteks need not apply--only dumb luck, educated guesses, and "let's try it and see if it works" admitted. I have a few of my own...
I think if you look at the timing, Shimano was deep in the R&D mode before the Suntour patent ran out, so they had engineering mules to work with, courtesy of Suntour. As they worked out the details, a few things come to mind, Shimano used a "floating" upper pulley, matched freewheel with very modest tooth reprofiling, a bailout friction option, Shimano chain and a elaborate tool to insure exact dérailleur mounting tab alignment. Of note, Shimano designed the alignment tool to work at first with Campagnolo hubs, knowing dealers most likely had those in stock to employ for the work. When the patent ran out, Shimano jumped to market with a product designed, produced and ready to sell. I would guess the patent filings would have given some warning to their competitors, but the market was theirs for a while.