When my trusty Fuji's VGT Luxe rear derailleur needed new pulleys - in the time before the Internet - and the LBS said that SunTour parts were obsolete, I ended up replacing the whole thing with something more modern just to get by... I have since acquired a 1st gen SunTour Cyclone GT for it, along with a NOS set of original SunTour roller-bearing pulleys that will go on at the next full overhaul. Probably the last rear derailleur it will ever need!

The '84 Univega Viva Sport I had picked up two years ago -- well, I decided to give it a detailed full overhaul since it was new-to-me and I didn't know it's maintenance history. Hoo boy... In addition to replacing things to suit my preferences (SunTour barcons for one), it got some upgrades as well. It also got 1st gen Cyclone derailleurs F&R to replace the original SunTour BL, along with a New Winner Ultra 13-21 6-speed freewheel, a Cyclone crankset, a VO cartridge bearing BB, a better seatpost (orig was cut off at the max ext line, not allowing enough to clamp!) along with a Brooks-clone leather saddle, new VO road pedals, newer GranCompe aero brake levers and new hoods... new bar tape, new cables... I spent more on the upgrades than I did for the whole bike!