I was doing a cleanup at the storage room and found a box of mint 105 parts (brakes, FD, RD, triple crankset and BB). Based on the newspaper inside the box, the parts were laying there for at least 10 years.
I have a vintage Nishiki road bike with friction shifters and 6-speed freewheel and would like to upgrade it with 105 parts if possible.
I assume the brakes, BB and crankset should fit no problem. However, I'm a bit concerned whether the rear derailleur (Shimano 105 RD-5501) would work with friction shifters (SR Suntour, mounted on the frame)? And what speed freewheels might be compatible with it?
I don't have much experience with vintage bikes and parts so I hope you can help me out and tell me if my idea to upgrade the bike makes any sense?