Yes, I know, throw it out. No way. the bike is 95% original and I hope to get it 100% some day. I am having trouble shifting onto the small chain ring and need to adjust the rear too. Can't find any picto-instructions on the web. Thought I'd ask y'all.

Which model?

Dunno.
These ones:

Ah. Prestige.

You sure you don't want to throw them out?

It won't be a problem if he rides the bike as they will break in a very short time anyway. Roger

You could pay a visit to Harris cyclery to see if one of their wrenches can show you some of what it takes to adjust the old Simplex's. In the day, Prestige's did give acceptable performance when new but also wore out rather quickly. Good Luck!

The rear is adjusted like any other RD, but the FD is rather unique. I could show you, but describing how to do it is not so easy.

The front is easy to adjust:

1) Set the height so that the cage clears the large chainring by 1mm.
2) Put the bike in first gear, making sure the front shift cable is slack.
3) Loosen the set screw on the cage and adjust the lateral position of the front derailleur cage so that its inside edge clears the chain by a couple of mm. Adjust its rotation so that the cage roughly follows the profile of the outer chainring.
4) Now shift into the highest gear and adjust the front derailleur's limit screw so that the cage's outer edge clears the chain by a couple of mm.

The rules are pretty much the same for the Campagnolo Gran Sport and Valentino.
4)

I had a set of those old Simplex plastic derailleurs on my mid 1960's Peugeot UO8. The rear worked pretty well, but the front was absolutely terrible. The front cage moves straight in and out horizontally and does not move down to properly guide the chain on and off the small inner chainring. As a result, I was constantly dropping the chain when shifting down to the small chainring and it took enormous effort to get it to shift back up to the large outer chainring. Eventually the plastic housing broke, and I replaced it with a Suntour that worked much better.

I think that the earlier Peugeots had a smaller small chainring and that type of FD doesn't handle those well. They work fine if there's not too much difference.

None of my Simplex FD's of that type allow the rotational adjustment that John mentions. The flat spot in the rod that the set screw runs up againt sets the angle. Also, I push the shifter all the way forward and remove any excess slack from the cable before doing any adjustments

Your rear derailer is not the common Prestige, but the Criterium model. I still have the original from my '74 PX10 and it would still work if I gave it some new pulleys. The front is a Prestige.

On the front, tighten the clamp until the plastic breaks, then replace with something that works...

The rears seem to keep working until the jockey wheels are worn round...

You've got a good point there. My Peugeot UO8 had a steel cottered crank, and if I remember correctly the chainrings were 52-36, which is a 16 tooth difference. From the photo in this thread, it looks like the crank is some sort of Stronglight aluminum cotterless model, and the difference is much less, so maybe it'll work OK.

You can get Bullseye pulleys on eBay for $18 a pair or two sets for $31. Put on some black or dark gray ones and it will look original but you won't have to worry about your pulleys disintegrating. I just put them on a Super LJ and an SX610 just for peace of mind.

Looks like a 49D.

Ok. I quit. What products are compatible with this bike?

You can substitute almost any older bottom-pull clamp-mounted front derailleur, although a few may require a thin shim for your 28.0mm seat tube's outer diameter. (The rest of the world used 28.6mm.) If your new front derailleur lacks a cable housing stop, just thread the housing under the bottom bracket shell and leave the end nearest the derailleur "floating." Great choices for your Peugeot are SunTour and Shimano -- I have a Shimano Titlist on my UO-8, and I had a 600 on my PKN-10. That original Simplex front derailleur is indeed cr@p. (I shouldn't talk, since I have its Campagnolo Gran Sport equivalent on Capo #2, but at least the Campagnolo's cage moves slightly upward as it moves outward, so that it tracks half-step gearing very nicely.)

I had forgotten about that flat spot, which shows how long it has been since I have had to deal with one of the fool things. I also neglected to mention loosening the clamp and twisting the unit around the seat tube as needed to put the cage parallel to the chainrings. Sometimes a very minute amount of inward bending of the inside cage face's forward tab will improve upshifts, but an excessive amount of bending will catch the chain prematurely and make things worse.

True.

My favorite FD for French bikes that need a stop is the Simplex SJA 102.



My favorite RD that fits a Simplex hanger without modification is the SLJ 6500.



The SX610 has the same geometry as the SLJ above and shifts just as well, but weighs 35-40 grams more. You can find them for much less money than the SLJ's, which are becoming horribly expensive.



If you want to use a non-Simplex RD, you have to butcher the hanger .



It doesn't show with the RD installed.



The catalog says that your bike originally had an SX410.

That derailleur fascinates me. It looks like you grafted the cage from a Campagnolo Rally onto a Nuovo Record body.

I broke down and ordered this last night:


https://yhst-84224226242177.stores.ya...si102frde.html

Excellent choice! It will work much better because it not only moves in and out but also up and down, and is much easier to adjust. It will last a lot longer beacuse it has no plastic parts. And it maintains the brand consistency.

Now you just need this:

https://cgi.ebay.com/ws/eBayISAPI.dll...m=200363122230

Good choice! I have a couple of those, and they work great!