The pulleys on Simplex rear derailleurs were notoriously brittle and would crack and break. And they got worse with age. The pulleys on my vintage Peugeot UO-8 were broken and chewed down to nothing. But like many other things on French bikes, they were made to different size specs than most other bikes. The bolt hole is 6mm, unlike Shimano pulleys which have a 5mm bolt hole. So most pulleys won’t work. Pulleys from another vintage Simplex derailleur are likely to be broken, waiting to break. But vintage Suntour pulleys will work. You might be able to find some new old stock replacement pulleys or take them off a vintage Suntour derailleur. I show how to remove, lube and install new pulleys on a Simplex derailleur.
**If the video was useful or interesting please give it a “thumbs up” and consider subscribing.