Friday, September 12, 2014

The Simpleton's Guide to Simplex: SLJ 5000

The following contribution, from special guest blogger Robert "Simplex Simpleton" Broderick, of, is a fresh installment from his "Simpleton's Guide to Simplex" -- not available in bookstores or online merchants, but first promulgated to the Classic Rendezvous group and available "free-to-anyone-inclined-to-read-this-drivel" (. . . this, in his own words). It is the first-ever "guest blogger" article posted to the Retrogrouch Blog.

CHAPTER XIII - THE SIMPLEX SLJ 5000 SERIES REAR DERAILLEUR (i.e., Real Derailleurs Are Made From Aluminum)

The first of the highly esteemed Simplex SLJ (. . . or Super Lucien Juy) series rear derailleurs, originally but briefly known as the Prestige Super L.J. debuted in 1972 as the SLJ AR 615, which was subsequently superseded by the almost-the-same-but-not-quite SLJ 5000 coincident to model year 1975.  The change in nomenclature was begot of Derailleur le Simplex having decided to undertake a wholesale overhaul of their derailleur model designations principally because they had begun to proliferate said model lineup to a point where their previous part numbering scheme could no longer properly provide a descriptive context (. . . as if it ever did in the first place).  The resulting reformulation of model numbers was intended to result in assignments that clearly articulated (. . . pun intended) the specifics of a given derailleur component . . . ASSUMING that one had the corresponding cipher key.  As previously discussed in CHAPTER IX - POST 1974 SIMPLEX DERAILLEUR CODES (. . . i.e., Taking a Swim in the Alphabet Soup) the Rosetta Stone explanation of Simplex model numbers dating from said era would be as follows:

Front Derailleurs:

Example: SLJ A 5 2 2
                   1  2  3 4 5


1 - Refers to the type of derailleur (simple back-and-forth movement vs. parallelogram) and defines place of model in the product line.

2 - "A" designation indicates that unit is a front derailleur (. . . the "A" being a reference to the French word avant, which not surprisingly translates to front in the English language).

3 - Composition of the derailleur, whereas:
     "0" - (. . . or digit missing altogether) Indicates a clamp-on mount having a Delrin body, metal (. . . either zamak or steel) front plate, and chromed steel chain guide.
     "1" - Indicates a clamp-on mount having an alloy body and front plate, steel parallelogram links, and chromed steel chain guide.
     "2" - Indicates a braze-on mount having an alloy body, steel parallelogram links, and chromed steel chain guide.
     "3" - Indicates a clamp-on mount having a Delrin body, steel front plate, steel parallelogram links, and chromed steel chain guide.
     "4" - Indicates a braze-on mount having a light alloy body, alloy parallelogram links, and chrome plated hardened steel chain guide.
     "5" - Indicates a clamp-on mount having a light alloy body and front plate, alloy parallelogram links, and chrome plated hardened steel chain guide.

4 - Type of actuating cable for SX and SLJ equipment only, whereas:
    "0" - Indicates cable with outer casing.
    "2" - Indicates bare inner wire only.

5 - Type of chain guide, whereas:
    "2" - Indicates standard guide for double chain wheel.
    "3" - Indicates larger guide for triple chain wheel.

Rear Derailleurs:

Example: SLJ 5000 CP / SP
                  1      2    3     4


1 - Refers to the type of articulation and defines place of model in the product line.

2 - Type of parallelogram.

3 - Type of cage, whereas:
     "CP" - Indicates cage axle centered between pulleys (. . . for racing gear ratios).
     "T" - Indicates cage axle off-center between pulleys (. . . for touring gear ratios).
     "GT" - Indicates cage axle off-center with long cage arms (. . . for grand touring).

4. Mounting specifications, whereas:
     "P" - Employs a mounting bracket.
     "SP" - Mounts directly onto fork end without use of a separate bracket.

Having established this wonderful convention, Derailleur le Simplex promptly went about wantonly violating same over the subsequent years with various product offerings (. . . albeit, primarily lower-end models -- but the inaugural SLJ A 500 pre-CPSC front derailleur also does not quite conform to this paradigm).  Therefore, the aforementioned guide should be considered a general rule of thumb and NOT a rigid and inflexible document (. . . unless you want to drive yourself stark raving mad).

As a direct consequence of the aforementioned part numbering re-alignment, it logically followed that contemporary Simplex catalogs identify discrete individual piece part numbers for those bits comprising the original SLJ AR 615 versus the first edition SLJ 5000 rear derailleurs and that said numbers are to some extent unique. However, those very same respective parts remained essentially unaltered from one model to the next, and in fact are almost completely interchangeable with one another -- at least until the second edition SLJ 5000 or if you prefer SLJ 5001 of model year 1978 (. . . in other words, Simplex may have changed the part numbers in name, but not the physical parts themselves). Exploded diagrams for these earliest SLJ offerings can be found as follows (. . . all diagrams reposted herein with acknowledgement to their host source at

Simplex SLJ AR 615:
Simplex SLJ 5000 CP (first edition):

Simplex SLJ 5000 T (first edition):

Simplex SLJ 5000 GT (first edition):

Over the course of its product life-cycle (. . . yep, another of those cursed puns), from inception in 1972 as the SLJ AR 615 through 1979, after which it was superseded for model year 1980 by the yet again remarkably similar but slightly improved SLJ 5500, the SLJ 5000/5001 rear derailleur underwent a few minor production modifications along the way.  

With regard to the new book Derailleurs of The World –Simplexwhile I wholeheartedly commend the author for undertaking such a daunting task and roundly congratulate him on a job “well done,” as with most things in life including many of my own endeavors, there is room left for improvement in my humble opinion. Sticking strictly to the topic of the SLJ 5000/5001 series rear derailleur and its precursor, the SLJ AR 615, there are but two variations which are documented therein – an original SLJ AR 615 and a  third edition SLJ 5000 CP or second edition SLJ 5001 CP (. . . depending upon your perspective – are you thoroughly confused yet?). I could quibble with the production dates cited, but I am of the opinion that any such discrepancy from my own understanding of “The Truth” is likely begot of the author’s omission, be it intentional or otherwise, of both the first edition SLJ 5000 as well as the second edition SLJ 5000 or first edition SLJ 5001.  My final oh-so-narrow critique of this fine book (. . . no sarcasm intended here – if you have any interest in refining your own knowledge regarding the oft perceived byzantine labyrinth of Simplex product offerings, this is the best, most concise place to start by far) would be that for whatever reason (. . . and there are many about which I could speculate and probably sympathize myself were I in his position of actually publishing a physical “book” as opposed to merely positing my punditry in dribs and drabs over the years) the author chose to omit pictorial evidence of anything other than the CP or “racing” version of these derailleurs (. . . an oversight which leads to circumstances such as persons inquiring as to why their third edition SLJ 5000 or second edition SLJ 5001 rear derailleur has such an apparently odd pulley cage assembly when compared to others they might have seen like the one in the book, and that would likely be because it is an SLJ 5000/5001 T as opposed to the close-ratio-oriented SLJ 5000/5001 CP – same derailleur body, same internal springs, same pulley wheels, same size or length pulley cage assembly as opposed to the ginormously long cage GT version, but said assembly has slightly different cage plates which are offset to one side and positioned at a different angle so as to facilitate greater chain wrap).  To be fair, at least the author has included a titular reference to the CP versus T versus GT models, but absolutely no pictures nor even a brief description as to just what differentiates each variation from one another.

Finally, we now get to the crux of a common query regarding a particular affectation of the Simplex SLJ 5000 rear derailleur, specifically with respect to the treatment of its cable stop. It is in fact, this very question that calls attention to the principal variation which defines not only the difference between the original SLJ AR 615 and its remarkably similar SLJ 5000/5001 successor, but also all three of the production versions of the SLJ 5000/5001 itself which occurred from 1975 through 1979. I have taken the liberty of attaching to this already lengthy missive a series of four photographs which can be used by those playing along at home to (. . . again, hopefully) differentiate each successive model:

1972 to 1975 – The original SLJ AR 615.  Note how the cable stop is cast directly into the upper body of the rear derailleur itself along its left side as you are facing same.  The bare cable end would proceed directly downward from here before passing through the lower pivoting anchor stop and being secured in place by a traditional hex headed bolt.
1975 to 1977 – The first edition SLJ 5000.  Again, the cable stop itself is cast directly into the upper body of the rear derailleur along its left hand side.  However, the outer upper parallelogram steel pivot pin (part number 3564 for the SLJ AR 615) has now been replaced by the 3932L similarly steel thread-ended pivot pin having a slotted head underneath which is fitted a circular plastic button. In this instance, the bare end of the derailleur cable would proceed downward from the integral cast cable stop and in front of the extended round plastic guide before passing through the lower pivoting anchor stop and being secured in place by a hex headed bolt. The purpose for this ever-so-slight modification which itself differentiates the previous SLJ AR 615 from the first edition SLJ 5000 is to better ensure that the taught cable will not foul with the parallelogram arms of the rear derailleur when fully extended outward (. . . whether or not this was an issue is largely a function of how much chain one was trying to wrap relative to the smallest cog on their freewheel) as well as to reduce the potential sheer effect of the bare cable which can otherwise enter the lower pivoting anchor stop at an oblique angle.
1977 to 1978 – The second edition SLJ 5000 or first edition SLJ 5001.  No longer is the cable stop actually cast into the upper body of the rear derailleur.  Rather, the 3932L steel pivot pin and circular plastic button head found on the previous edition SLJ 5000 rear derailleur has been replaced with a threaded steel pivot pin having an articulated or pivoting head which serves itself as the cable stop, and through which thereafter passes the bare derailleur cable downward before entering the lower pivoting anchor stop and being secured in place by a ridiculously saucer shaped CPSC-compliant Allen-headed bolt.
1978 to 1979 – The third edition SLJ 5000 or second edition SLJ 5001. In yet a further and final refinement of the twin pivoting cable attachment principle, there is now a black “extended tube” style cable stop/cable guide integrated into the pivoting head of the upper threaded steel pivot pin, through which the bare derailleur cable passes downward before entering the lower pivoting anchor stop and being secured in place by a hex bolt (. . . whether or not it has the saucer shaped CPSC-compliant head or a “normal” hex head depends entirely upon one's particular luck of the draw). This very same manner of “extended tube” style articulated cable stop would be carried forward on the SLJ 5500 series of Simplex rear derailleurs which debuted in late 1979 for model year 1980.
© Copyright 2014  R. S. Broderick – All Rights Reserved.


  1. Dear Robert,
    when I recently found this article while I was trying to classify a SLJ 5000 that I received, it really delighted me as this was the first really comprehensive summary of the history of a Simplex component and after lecture an unambiguous assignment of the component was possible. Yes one model only and there are so many others out there....
    As a very interested "Simplexologist" I can only congratulate to this most informative, precise and substantial article. And - I know which pain one has to go through in bringing up these details, specifically - you already mentioned it - because Simplex was not feeling bound to following their own rules which anyway sometimes appear quite weird. I know it must have been hours and hours of days searching, catalogue viewing, thinking, inspecting components repeatedly and closely finally believing you have understood and then fall into doubt just right after. In spite of all that I'm still a Simplex enthusiast (for whatever reason) at least for the components 'til mid 1980s. I think I have understood it means live time learning but never fully overcoming doubt.
    Thanks again for this great piece of research and compilation.
    Tobias Mundry

  2. Hello Robert,
    Thanks for this wonderful article for a fairly modern Simplex.
    I wonder however if you can help me in identifying my old Simplex gears. They are on a bike I have owned since 1959 and three bikes were built by Greyhound but two were believed to have been sold to overseas buyers. They were especially built for a 1958 race event here in Perth Western Australia. So in essence mine is most likely the only bike in existance of the three built. It has a Simplex four speed and is entirely original but the bike is in overall poor condition as storage was less than ideal. However because of its history and rarity I think it is worth restoring.
    Looking at pictures on line it looks like a Simplex TdeF model or very similar but as it was built in 1958 or therabouts and the TdeF model appears to have come out in about 1950 I wonder if I asm on the right trak.
    It is a bit hard to read but on the outside main bar it appears to have JUY SIMPLEX with the following under the word SIMPLEX - RUSGOG but the S could be a 9 and the O could be a D. Can you interpret those letters ?
    I can send you a photo if it is not possible to make anything out of the letters but would need your email address.
    With thanks and hope you can help. I think it would be best if I can be sure of the Simplex model to sourse parts.
    Thanks Barry Peterkin