Saw an old bike recently in my stand... didn't have a label; It'd been repainted orange, yellow, green fade. I think it was some older Bianchi maybe. It had some Suntour Edge components. He used friction cyclone downtube shift levers and a 26T max shimano FW and it shifted fairly well in that mode. What I've heard on the older Suntour index was 24T in indexed, and 28T in friction mode. The shifting doesn't work in indexed if you have Suntour/Suntour RD and Levers together. It a bit off either at the big cogs or at the small cogs in terms of spacing. But I have gotten Shimano shifters and Suntour RD to work with Shimano FW. Not sure if that helps.