Have: a direct-mount (no claw) Simplex 610 RD. It's in good shape, and is the "touring" model with the pivot at one end of the derailleur cage. I believe that it will take a 28- or 30-tooth cog, based on what I've heard from others around here. It's used but in good shape--I've never used it myself.


If my understanding is correct, the 610 used a Suntour-inspired slant parallelogram design; I've heard that Simplex abandoned the design after a short time, possibly because it ran afoul of one or more Suntour patents.


I'd like to trade it for a similar Simplex long-cage or "grand touring" RD. I'd consider the long-cage version of the 610, 810, or 410.


I can provide some photos if anyone is interested. The derailleur is branded Simplex, but has a Motobecane logo on the Simplex sticker, if that matters.