Re: [CR] Simplex CX630 Rear derailleur

Example: Production Builders:Frejus

Date: Wed, 13 May 2009 12:44:09 -0500
From: John Thompson <>
Organization: The Crimson Permanent Assurance
To: <>
References: <>
In-Reply-To: <>
Subject: Re: [CR] Simplex CX630 Rear derailleur

Fred Rednor wrote:
> During the early and mid-1980s, a popular variant of the derailleur
> in question was the Simplex SX 610T. Theses were used by Peugeot on
> the "semi PX-10" type bikes. By that I mean models like the PSV-10,
> PF-10, PGN-10 and so forth.
> In any event, this derailleur shifted nicely and _appeared_ to be of
> all aluminum construction. The trick was that the outer arm of the
> parallelogram used some plastic reinforcement that was not visible
> when it was mounted on the bicycle.
> Something I noticed with many of these bicycles was that the frames
> were built with Simplex dropouts that were already threaded for
> Campagnolo derailleurs. It did seem a bit incongruous for a Simplex
> derailleur, which used the traditional Simplex mounting, to be
> installed on a Simplex dropout that was machined to take someone
> else's derailleur - but such was the state of the French bicycle
> industry in those days.
> The truly detrimental aspect of this situation, though, was that it
> provided an enticement to replace the Simplex mechanism with a
> Campagnolo part. I did this a couple of times and discovered that,
> while it was an aesthetic improvement, it was detrimental to shifting
> performance.
> I suppose you could catalogue all this as another variation of
> Jerry's experiences...

I have a bag full of these NOS Simplex drive-side rear dropouts I use to replace broken dropouts:

Note that they are already threaded 10M x 1.0


-John Thompson (
Appleton WI USA