To quote that which I posted to the CR List back around Thanksgiving of 2010, "Bernard Thevenet ... won the Tour de France in 1975 whilst employing a Gold anodized SLJ A 500 front and SLJ 5000 CP rear derailleur.... However, when he won again in 1977 he was using an SLJ A 502 front pull front derailleur in combination with a LJ 4000 CP in the rear."
To add a bit more substance to that statement, Peugeot-BP-Michelin team riders used Gold anodized SLJ 5000 CP rear derailleurs during the 1975 season, Peugeot-Esso-Michelin riders used clear anodized and Silver hued SLJ 5000 CP rear derailleurs throughout 1976, and as of 1977 they began using Delrin based LJ 4000 CP rear derailleurs (...of course, there was one exception - Regis Delepine). This practice continued until 1986 under Peugeot-Shell-Michelin sponsorship, although as of 1981 I believe (...could be 1982, I would have to dredge out the collection of Miroir du Cyclisme to confirm exactly which year), the LJ 4000 CP rear derailleur versions used were a "team only" special edition featuring ample "drillium" and incorporating several otherwise "non-standard" lightweight piece parts. For a glimpse at an example of just such a late model "team only" rear derailleur, please use the following link:
http://www.velo-pages.com/
As circumstance would have it, I actually own a 1986 Peugeot PY-10 FC carbon bike just like the Peugeot-Shell-Michelin team employed from 1983 through 1986 (...through 1987, if you count their team Z Peugeot successor), but I am not quite sure that I want to trick it out as a team bike replica (...unlike my current 1977 Peugeot PY-10 CP project) or otherwise "waste" an NOS example of an extremely rare component.
With regard to their "worthiness" and just why the team bikes eventually gravitated to the Delrin based rear derailleur models, it has been my observation and experience that they weigh considerably less than their aluminum SLJ counterparts (...kinda obvious - and that is certainly a consideration with respect to professionally competitive venues where grams can make a difference) and they are also every bit as good with respect to performance (...otherwise, I believe that the Peugeot team would not have tolerated such a substitution - but then again, Thevenet was riding MAFAC Competition center pull calipers, albeit braze-on mounted versions, when he won the Tour in 1977, and that was the very last instance of such a venerable component laying claim to victory) But there is a HUGE caveat that should be noted. Peugeot team riders had the luxury of having their various componentry replaced daily in some cases if not more often (...think chains, freewheels, tubular tires, etc.). So, component longevity was not really much of an issue for them. And while the self lubricating nature of those Delrin based rear derailleurs is integral to their providing excellent performance "out of the box", once their joints have been subjected to the abrasive nature of road grit and grime over a prolonged period of time (...just how "prolonged" usually depended upon how much dirt you rode through or how often you pedaled through puddles and the occasional rain shower), the crisp nature of their shifting gives way to a more amorphous feeling that can leave you guessing as to just where that pulley cage might actually be at any given moment (...unless it finds its way into your spokes, in which case, you will immediately know its exact location).
The bottom line from my perspective is this: like most things in life, use them within the scope of their original intent and you will likely be most pleased by their performance....
Robert "just avoid riding in the rain" Broderick ...the "Chronically Cloudy Clime" of Oregon Portland, USA
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of r cielec Sent: Friday, January 21, 2011 9:51 PM To: Classic Rendezvous Subject: [CR] Gipiemme/Simplex LJ4000 CP Ders- Any Good ?
Ahoy !
Re: Gipiemme/Simplex LJ4000 CP Front and Rear Ders- Any Good ?
Truly, not fishing but, merely trying to figure out what to do with this derailleur set.
The rear has the delrin bodies, not aluminum.
I am guessing these are average OK front and rear derailleurs suitable for a mid-range quality bike. Is this an accurate assessment?
Yes, I've been seeking Gipiemme/SLJ ders for a lingering project. but may use this LJ4000 set until I find the others.
Thanks.
Richard Cielec
Chicago, Illinois; U.S.A.