I just got a 1986 Centurion Iron Man that came with full Shimano 600 6 Speed SIS and Dia-Compe Gran Compe aero brake levers. While working on the bike I noticed that the brake levers do not have return springs and the brake calipers have super strong return springs (as compared to my 1989 Shimano 600 single pivot brake calipers). I gues this makes sense so that combo would work well together. But because the Shimano levers are more comfortable to me, I put on older Shimano brake levers to see how I would like them as compared to the Dia-Compes. Unfortunately I found it took a lot of sqeezing force to stop the bike, so I switched back. Then I saw a photo of Raul Alcala on the 7-11 team from 1986. I could see from the photo that he used what looked like the same generation brake calipers as mine but he was using Shimano levers. My question is this: Did Shimano make brake levers in the mid '80s without the return assist spring or is Alcala just using the combination of caliper/lever that takes a lot of strenth to pull?