Hi Everyone... I was hoping you could help a newbie out. I'm relatively (6-8 mos) new to cycling, and I decided to build a dedicated commuter, hopefully something with a little style.

I found a 1989 Schwinn World (not sport) for $60 on CL and scooped it up, but as I'm learning more about the bike, I can't seem to identify the derailleurs. The shifters and rear derailleur are simply marked "Shimano SIS," and the front derailleur is marked only "Shimano."

The only group that Shimano called "Shimano SIS" was a MTB group from the early 90's. Everything else that I can find is "Shimano Exage SIS" or "105 SIS" and so on. I imagine this is a simple question, but I want to know as much as I can about what I'm riding.

Thanks in advance.