Originally Posted by
Roypercy
My current ride is a 1982 Grand Jubilee, a bike I like a lot. It's pretty much all original. It came stock with Simplex SX610 derailleurs, which have always been, well, ok. But lately I'm finding the rear derailleur is going out of adjustment pretty frequently and I have a lot of trouble keeping it dialed in: either it won't want to go onto the biggest chainring, or it won't go onto the smallest.
Since I've never been all that crazy about the Simplex anyway, I'm thinking about upgrading.
The RD is a Simplex SX 610 GT/SP with a 34T large freewheel sprocket capacity. They shifted about as well as pre-SIS Shimano and Suntour friction RDs.
Not shifting to the small sprocket can mean the derailleur needs to be thoroughly cleaned and lubricated, same with the cable and housing. A worn upper pulley can cause shifting problems too. Also check the upper and lower limit screws. Clean and lube the chain too.
I have a Simplex SX 610 GT/SP on my 1980 Moto Grand Jubile (still called Grand Jubile in 1980).
Originally Posted by
Roypercy
What puzzles me is the dropouts. They aren't branded "Simplex"; the only engraving on the dropouts I can see looks like "CO". What's also weird is, the rear derailleur isn't just screwed directly into the dropout, there's some sort of washer with a built-in stop between the derailleur and the dropout. My experience with this stuff is pretty limited; usually in the past I've worked on maintaining the parts I had, rather than replacing them. My wife's Grand Touring has Suntour dropouts and Suntour derailleurs, and I had expected my bike's dropouts to be branded "simplex" but it looks to me like something else is going on.
I've never seen a Motobecane with Simplex dropouts. They used Campagnolo, Huret and Suntour dropouts with integral derailleurs hangers on their mid range to top quality models.
Per [MENTION=20650]T-Mar[/MENTION] in message 8, the dropouts on your bike were made by Huret. Motobecane used them on a lot of their models from ~1978 through the early 1980's. They appear to have been made of investment cast steel.
The derailleur hangers on most Huret dropouts from the mid 60's until the mid 70's were a proprietary design that only worked with Huret derailleurs.
By the mid 70's Huret gave up their fantasy of world domination and changed their derailleurs and dropouts to be compatible with the de facto standard Campagnolo design.
You can mount most brands of 1970's and later C&V derailleurs on your bike without any problem - except for early 70's Huret RDs which require an adapter.
That's not a washer on your Simplex RD. It's the travel limit stop that's part of the derailleur. There's several different styles.
A word of caution, don't try to remove Simplex derailleurs by removing the nylon plugs in the hex openings in the pivot bolts. Those hex openings are only for adjusting the pivot spring tension.
Loosen the mounting screw on the inside of the dropout.
Originally Posted by
Roypercy
Anybody know what I've got here? I'd love to switch to Huret something, since my last two vintage roadbikes had Huret derailleurs and I like their action a lot more. And it would be at least keeping my GJ as French as possible. What else might be compatible without too much fiddling?
Simplex and Huret (later called Sachs-Huret).
verktyg
Chas.