Re: [CR] Simplex CX630 Rear derailleur

Example: Events:Cirque du Cyclisme:2002

Date: Tue, 12 May 2009 12:36:53 -0700
From: Fred Rednor <>
To: <>
Subject: Re: [CR] Simplex CX630 Rear derailleur

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...
      Fred Rednor - Arlington, Virginia (USA)

--- On Tue, 5/12/09, Jerome & Elizabeth Moos wrote:


\r?\n> Note the mix of alloy, steel and plastic on the mid and low

\r?\n> priced models.  And even the top range has one RD that

\r?\n> is part plastic.  So even at this late date Simplex had

\r?\n> not entirely given up their fascination with plastic. I

\r?\n> think it was their long-time attachement to Delrin that in

\r?\n> large part led to their undoing. 


\r?\n> When they first introduced their Delrin derailleurs about

\r?\n> 1960, plastics were still considered advanced "space age"

\r?\n> materials.  But by the mid 70's they had begun to be

\r?\n> associated with cheap goods, so what may have made Simplex

\r?\n> look advanced a decade and a half earlier caused their goods

\r?\n> to seem "cheap" during the Bike Boom. They also used plastic

\r?\n> in some inappropriate places, notably the horrible plastic

\r?\n> Prestige DT shift levers for which most of the force applied

\r?\n> went to flex the levers.  Another poor decision was the

\r?\n> use of a cheap and thin stamped steel jockey cage on the

\r?\n> lower priced Prestige RD, which combined with the plastic

\r?\n> shift levers made for very sloppy shifting.  This

\r?\n> combination appeared on large numbers of Peugeot UO-8s and

\r?\n> similar models from other French manufacturers sold un the

\r?\n> US during the Bike Boom.  I had such a UO-8, and within

\r?\n> a year I replaced the derailleur with Shimano Titlist. 

\r?\n> Probably tens of thousands of Simplex

\r?\n> derailleurs were replaced with Shimano and SunTour by

\r?\n> American buyers in the 70's


\r?\n> Unfortunately the poor performance of the Prestige

\r?\n> tarnished the reputation of the entire line.  The top

\r?\n> of the line Criterium RD in the early 70's, with a proper

\r?\n> forged jockey cage and paired with proper forged alloy

\r?\n> Criterium shift levers, shifted far better than a Campy

\r?\n> NR.  But it had a plastic body like Prestige and looked

\r?\n> the same to American buyers, many only just learning about

\r?\n> quality lightweight bikes and components.  And the fact

\r?\n> that both Prestige and Criterium RDs at the time were marked

\r?\n> "Prestige" further confused the issue. 


\r?\n> So much so, that when I bought my LeJeune F-70 (PX-10

\r?\n> equivalent) new in about 1973, I had the shop change out the

\r?\n> plastic Simplex Criterium for the then new alloy SLJ, based

\r?\n> on my bad experience with the plastic Prestige. 

\r?\n> Probably would have changed to a Shimano or Suntour except

\r?\n> for the issue with the Simplex DOs. Quite a few PX-10s also

\r?\n> wound up with Campy NRs even though one had to go to the

\r?\n> trouble of tapping and notching the Simplex DO to fit the

\r?\n> Campy.  Only after I joined the CR list decades later

\r?\n> did I learn that that origianl plastic Criterium I had

\r?\n> changed out would have shifted as well as the more expensive

\r?\n> SLJ and much better than the Campy NR that some guys went to

\r?\n> so much trouble to fit to French racig bikes.


\r?\n> I think my experience was pretty typical of the reaction of

\r?\n> the US market to Simplex In The Day, partly based on our own

\r?\n> ignorance of European equipment, but also influnenced by

\r?\n> some poor decisions by Simplex, but technical and in

\r?\n> marketing.  I was going to say Simplex had learned

\r?\n> their lesson with the later models in the catalog posted

\r?\n> today, as the RDs all seem to have proper cages and the

\r?\n> derailleurs use plastic to save weight on bits not subject

\r?\n> to a lot of flex.  But unfortunately, the low and mid

\r?\n> priced groups still include plastic shift levers.  Most

\r?\n> look a bit stiffer than the early 70's Prestige shifters,

\r?\n> but shifters are just not a sensible application for

\r?\n> plastic.


\r?\n> Most of this later Simplex gear and a lot of the earlier

\r?\n> stuff, was very good, and indeed it was Coppi's TdF victory

\r?\n> using Simpex derailleurs that finally shocked Campy into

\r?\n> introducing a cable operated parallelogram RD.  But

\r?\n> Simplex made some major missteps in the market that opened

\r?\n> the door for SunTour and especially Shimano and eventually

\r?\n> led to the decimation, though not quite total destruction of

\r?\n> the French bicycle component industry.


\r?\n> Regards,


\r?\n> Jerry Moos

\r?\n> Big Spring, Texas, USA





\r?\n> --- On Tue, 5/12/09,

\r?\n> <>

\r?\n> wrote:


\r?\n> > From:

\r?\n> <>

\r?\n> > Subject: Re: [CR] Simplex CX630 Rear derailleur

\r?\n> > To:,


\r?\n> > Date: Tuesday, May 12, 2009, 4:01 AM

\r?\n> > Greetings Jon & all,

\r?\n> >

\r?\n> > Not familiar with a CX 630, might we  be

\r?\n> considering an SX

\r?\n> > 630?

\r?\n> > Here is a circa 1983 or 1984 Simplex Catalogue which I


\r?\n> > had scanned and uploaded in its entirety. 

\r?\n> >

\r?\n> > One SX 630 model  shown on page 8 and another

\r?\n> variant

\r?\n> > with a longer cage on page 12. 

\r?\n> > 

\r?\n> >

\r?\n> >

\r?\n> > A  useful source of info on later era Simplex

\r?\n> derailleurs,

\r?\n> > these pages give details of the recommended cog and

\r?\n> > chainring sizes and the total chain wrap

\r?\n> capacity.  Within

\r?\n> > the different groups (referred to as bronze, silver,

\r?\n> gold -

\r?\n> >

\r?\n> > which were essentially quality & price point

\r?\n> > distinctions),

\r?\n> > you can better distinguish from the photos the

\r?\n> differences

\r?\n> > between the sometimes quite similar models, but often


\r?\n> > with surprisingly dissimilar gear ranges.

\r?\n> > 

\r?\n> > These were the "final" evolutions of many late

\r?\n> > Simplex

\r?\n> > derailleurs.  Many models were definitely little

\r?\n> changed

\r?\n> > from the late 1970s models. I suspect all worked

\r?\n> pretty

\r?\n> > nicely... but, by this era Shimano was also producing

\r?\n> a

\r?\n> > wide selection of derailleurs as well... which were

\r?\n> > probably

\r?\n> > just as good, or better, and maybe a bit cheaper than

\r?\n> the

\r?\n> > best of the Simplex derailleurs.

\r?\n> > 

\r?\n> > I noticed in an early 1980s Motobecane catalogue that


\r?\n> > the Team Champion was using the Super LJ 6600 with a

\r?\n> > tri-color "M" logo added right beside the Simplex

\r?\n> > script on

\r?\n> > the outer parallelogram plate, so they were still

\r?\n> highly

\r?\n> > regarded... at least for the French domestic market,

\r?\n> where

\r?\n> > they would also have been competitively priced against


\r?\n> > other imported marques.

\r?\n> > 

\r?\n> > Many of these derailleurs may still be good values,

\r?\n> priced

\r?\n> > far below the exalted market prices of the earlier

\r?\n> 1970s

\r?\n> > models, so these pages may be worth downloading and

\r?\n> > saving in your PC files... especially if you are a

\r?\n> > Francophile

\r?\n> > bargain hunter and could benefit from a "field

\r?\n> > guide" to

\r?\n> > help distinguish between the ranges and features of

\r?\n> all

\r?\n> > these models.

\r?\n> >

\r?\n> >


\r?\n> > 

\r?\n> > **************A Good Credit Score is 700 or Above.

\r?\n> See

\r?\n> > yours in just 2 easy

\r?\n> > steps!

\r?\n> > (

\r?\n> > =Mayfooter51209NO115)