At least, that is what I think this model is:





Anyway, I like it, and I want to use it.

However, I can't figure out how to mount it correctly on a Campagnolo hanger. If that is at all possible.

The problem is that the tab that should keep it at the right angle is not in the expected position, which is - more or less - at one o'clock (viewed from the drive side).

The location of the spring and the slot in the mounting plate keep the tab firmly at five o'clock:






The only thing I can think of is that this was meant for a Huret hanger. Or am I missing something?

I've checked this forum's posts that I could find on the Simplex Criterium - amongst which this helpful one by [MENTION=61614]verktyg[/MENTION]. They all show the later model, which has the spring in a different location. So I can't replace the mounting plate with one from a later model.

Thanks in advance for any information that may help.

The "official" name of the derailleur that you have was the Simplex PresTige CRITERIUM AR537.

There's some conflicting info on velobase.com and on https://www.disraeligears.co.uk. I'm going with information on velo-pages.com.

The Simplex PresTige CRITERIUM AR537 was introduced in 1966 and in production until 1970 when the then new (and improved) CRITERIUM AR637NI replaced it.

PresTige became name of the PRESTIGE model which was the omnipresent black Delrin derailleur that destroyed the French bicycle industry!

The "NI" indicates the derailleur was designed to attach directly onto a dropout with an integral gear hanger. The "P" version came with a "Claw Hanger".

1966 Simplex PresTige CRITERIUM flyer from velo-pages.com




I liked these older model derailleurs with the dark blue face plate better than the ones with the shiny silver foil parallelograms. I only recall ever seeing a few of them "in the flesh".

By the time I got into working on French bikes back in 1973, most of the 537 RDs had been replaced. They had some weaknesses - see below.


Huret? NON! NON! NON!

The problem is the upper pivot bolt is damaged.



It should have flats on the end like this one to fit into the travel stop plate:



This is the stop plate from a 637 but it shows how it should fit over the pivot bolt.



Another later model Simplex RD. They continued using this poorly designed "feature" until the bitter end.



Munged end on the upper pivot bolt. This happens when someone tries to remove the derailleur with the hex opening in the upper pivot. It rounds off the end.



I've been able to save some of these pivot bolts by carefully forcing the end to fit into the stop plate using a tapered punch with a sharp point.



All of the post 1970 RD had plugs in the hexes to prevent this.

1971 CRITERIUM AR637P - notice how the travel stop tab fits over the front of the dropout hanger. This is a Campy dropout but it works the same on Simplex dropouts. Also note the red nylon plugs. Later all metal Simplex RDs had natural colored nylon plugs.



I don't think that you'll be able to repair the pivot bolt end on your RD. It takes a part number 2549 which may be next to impossible to find to around a 50 year old derailleur that wasn't very common.



You may end up having to use the more common AR637NI derailleur. Good luck.

verktyg

Thanks, Chas, for your elaborate reply. Much appreciated!

I hadn't even got to the point where the mangled pivot bolt would have become a problem. Thanks for pointing that out. Saves me a lot of time and frustration.

I have a other - newer and better - Simplex derailleurs, but this particular one would have looked really nice on my 1968 Jacques Anquetil. Oh well.

What I'm still not getting, though, is the five o'clock position of the tab. It is purely the result of the locations of both the spring end and the groove in the stop plate (part 2580). My initial reaction was the same as yours (Huret? NON!), but I still haven't any other logical explanation.

I looked for a replacement stop plate in my parts bin last night, but the ones I have are all like the one below you posted. They require a "ledge" which the 537 doesn't have.



I think I'll mount a newer SX-somethingorother for now, but the 537 looks awfully pretty with its blue hue, and I'll keep looking for a new pivot bolt and Simplex-compatible stop plate.

The stop plate that you have IS the correct part. Those Simplex derailleur stop plates look weird until you mount them onto the dropout. There is a small amount of preload in the upper pivot when the tab is placed over the leading edge of the dropout that will correctly position the derailleur.

Newer all metal SLJ derailleur showing where the stop tab should sit. Simplex used this method from the mid 60's until the end. It allowed their derailleurs to be mounted on most dropouts including proprietary Huret dropouts (with a little modification).



You probably caught this but the upper pivot needs to be pushed further in so that the spring engages the slot in the stop plate. What a Rube Goldberg design!



verktyg

I'm possibly not getting it here, but it appears tome that the stop plate, mounting bolt and retaining screw ALL are stationary WRT the dropout, and can thus be held in place merely with firm tightening of the retaining screw.
Am I wrong about this?

It also seems to me that the two ends of the spring engage the upper knuckle and the head of the mounting bolt, respectively, not the stop plate.

So I am thinking that if the assembly is mounted up, that as the retaining screw is tightened, a 5mm Allen key can be used to preload the spring just as much as needed (for the particular largest cog, with the chain on the small chainring).

That is what I would try.

Am I overlooking anything here?

Thanks for that picture. Very useful. It is exactly how every Simplex derailleur I have looks when mounted: the tab that grabs the hanger roughly at one o'clock.

Except this particular one.

Let me explain. I like your style of presentation, so I hope you don't mind me copying it:



While I think - and this is corroborated by your pictures and my experience - it should end up here (please excuse the lousy artwork):




"IST", BTW, is German for "current situation" and used a lot here in Holland to explain the difference with "SOLL", which is (again) German for "how it should be":

So, what is it that I'm not understanding here?

"Possibly not getting it" is an accurate description of my frame of mind.

Yes, the spring ends engage the upper knuckle and the head of the mounting bolt. And yes, turning the mounting bolt will preload the spring. The problem seems to be the position of the spring end in the upper knuckle in relation to the slot in the stop plate, which places the tab that grabs the hanger at five o'clock rather than one o'clock where I think it should be (and where it is in Chas' picture).

To the OP, note that the derailer's upper knuckle swivels on the mounting bolt, but that the stop plate remains in fixed position to the dropout.

So, with the end of the spring "keyed" into the hole in the plastic upper knuckle, you would not want the same end of the spring to in any way "engage" with the stationary stop plate, as this would prevent the spring-loaded pivot from functioning.

So note that, with the parts properly oriented, that the end of the spring will never coincide with the location of the "groove" in the back of the stop plate (that "groove" is I believe some sort of metal-forming trick designed to improve the strength of the bent tab that engages the front edge of the dropout).
It may also be that the end of the spring isn't long enough to actually engage with the "groove" in the back of the stop plate(?).

Sorry non-fixie, I am just now seeing your above post!

Who's on second, anyway?!!

The spring is long enough to engage with the groove. And so far I've been thinking it is actually supposed to do so, hence my mental suffering ...

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Thanks for beginning this discussion [MENTION=173992]non-fixie[/MENTION]!

One of these mechs came on the PX10E I purchased nieuw in 1970.

Happily, it never required fiddling during the time I owned the machine.

With Chas. on the case we are in fine hands.

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