Originally Posted by
grumpus
Looking at classic derailleurs but ignoring pre-parallelogram designs, the Suntour Superbe is the only one I could find with 23t max, Suntour Cyclone and V Luxe were 24t along with a few like Simplex Prestige, Huret Jubilee etc. Then skip to 26t for Campy Gran Sport, 980 and various Record, NR, SR models, Suntour Vx and Cyclone II, and Dura-Ace. Finally 28t for Shimano 600 and "bird" models.
I thought there was a old Shimano RD I looked up for someone in another thread that was 23 teeth for the max low sprocket. Maybe not.
Still, the advise remains.... One should check the spec's of their RD to know whether they are within spec. Or are about to be experimental. Not that going out of spec means immediate failure. Given a choice of RD's, new or used I'd get the one that's in spec.