Hi, I'm replacing the pulleys on my '72 Peugeot (simplex derailleur). I watched a few videos on youtube and it was recommended I get a Suntour pulley. It came in today and I realized:

1) it has 12 teeth rather than the 10 on the simplex pulley
2) the bearing diameter is too narrow for the pin

Would replacing both 10-tooth pulleys with 12-tooth be ok?
Could I just drill out the bearing to fit the pin?

If no to either/both, would this pulley work?
ebay.com/itm/Sun-Race-SP850-Rear-Derailleur-Pulley-10-Tooth-Plastic-Black-Bike-Bicycle/391609613276

You may be better off trying this question in the Classic & Vintage forum, where there’s a wealth of vintage Simplex & SunTour experience to share.

As for my own personal experience with the Simplex Prestige derailleur... I replaced the whole darn thing on my UO-8 with a SunTour V-GT. Not only were the Simplex pulleys cracked, the plastic body of the derailleur was, too. (This is supposedly a less frequent problem on the rear derailleur. The fronts are notoriously fragile and brittle, though.)

Sounds good - thank you! I'm off to look at SunTour V-GT's now.