will these shifters work with a suntour setup on a 1991 Giant Iguana? Its has SUNTOUR 6 speed accushift shifters now. It has a Suntour 3040 front and rear derailleur and a shimano rear cassette. Thanks for help.



https://www.amazon.com/Sunrace-Mount-.../dp/B000A6FF72

For the Sunrace shifters to work correctly, you will need to install a Shimano index-compatible (essentially anything made in the last 25 years) rear derailleur. Shimano-compatible shifters won't index correctly with a Suntour derailleur.

I'm surprised it works now with the Shimano cassette. Suntour used slightly different spacing in it's freewheels.

Sheldon Brown explained this here:

Surprisingly, though, if you have Sun Tour 6-speed indexed shifting, you can convert to 7-speed using your present shifters! All that is needed is to replace your old rear derailer with any Shimano unit. Shimano vs Sun Tour indexing is different, but the mismatch in brands turns out to cancel out the mismatch 6 vs 7, so this actually works pretty well! The low gear position won't have a "click" in the shifter, but the derailer's low-gear limit stop will provide the "indexing" function for the low gear.

So sorry i am new but if i put shimano tourney rear derailleur, sunrace shifters, and have a shimano cassette it will work?