I obviously need to replace the front derailleur and two questions answered. First is what would be a suitable replacement? This bike has down tube shifters. The second question is can I take the cage off the simplex and swap it out with the cage on a replacement? I like the look of the simplex cage and would like to keep it if possible. I don't want another plastic simplex FD as it will most likely crack again. The bike is a mid 70's Peugeot AO-8. This is my first restoration project and I am a complete rookie so any help is greatly appreciated. Thank you in advance!

Simplex is not made by Shimano. One was A French Company.

just look for a Suntour Vx or V GT. Change the RD while you are at it.

https://www.disraeligears.co.uk/Site/...-_Page_15.html

Absolutely ^ replace both derailleurs. Nice alloy SunTour Vx from that era would represent an upgrade. Sell the Simplex rear on eBay to offset part of the costs...

Is there a market for cheap simplex derailleurs? You could try out the local bike collective or co-op and try to find an old school derailleur that will do the job; your LBS might have old derailleurs lying around that they are willing to sell.

The cages with the Simplex logo are kind of cool. You might be able to find a body that hasn't cracked, and replace your cracked one. Just to keep the bike original. But, many of them do crack. Not all, though. I have one that is 40 years old and not cracked. Yet.

Be aware that you may have to shim the replacement derailleur to get it to sufficiently tighten to the seat tube. French bicycles used slightly smaller diameter (28mm) seat tubes versus the 28.6mm that most front derailleurs are designed around. Some derailleurs have very stiff clamps that are not ductile enough to form to the slightly smaller diameter seat tube.

If you want to stay with a French derailleur, just move up to a newer all metal Simnplex derailleur set and you will be much happier too as they will shift much better. Check out the simplex SX610 rear and the front derailleurs that match up to them. The plastic (Delrin) derailleurs from Simplex just don't do too well on bikes after a few decades of off-gassing their plasticizers into the atmosphere, which causes them to becom brittle and eventually crack.

Techincally if it's a 'restoration' you're doing, you should replace the original with another plastic Simplex of the same kind. I've got one in my parts box you can have cheap if that's what you really want.

If you're more interested in cleaning the bike up and making it better for riding again, almost any Suntour or Shimano derailleurs you can get will be better than the old plastic Simplexes (which is why I have an old Simplex in my parts box, rather than on a bicycle )

You bet. Check out ebay, some go high. Ridiculous for cheap plastic derailleurs, but so many break that the supply of unbroken ones is limited, and some people want exact replacements for their restoration.

+1 On LBS left overs. I picked up a nice Deerhead RD at a nearby LBS for $6....

This RD sold for $55:

https://www.ebay.com/itm/SIMPLEX-Pres...p2047675.l2557

Several others sold for $30 plus, front or rear.

Thanks for all the comments. I probably used the wrong term in restoration but my goal here is to clean and shine it and be able to ride it occasionally around town. I have no qualms about switching out the FD and RD for a more modern one. It looks like the Suntour ones will at least look appropriate. Is it possible to use a modern FD like a 105 with down tube shifters?

The frame is pretty badly scratched on the seat stays and fork and I was considering a complete repainting of the frame but that seems like overkill. Can the paint be touched up without removing the stickers? Below are before and after pics of the front brakes after removal and cleaning.



I have also cleaned the wheels.


The leather saddle needs some reconditioning.

+2 Suntour VX GT derailler set would be my choice fairly inexpensive and about the best era correct derailluers for this bike. I would also spring for a a set of Suntour powers shifters so you have a matched group. If you shop around you can find all three for around $40-50.

Modern derailleurs will work fine with downtube friction shifters. But you will have issues with the claw hanger in the rear and the clamp size on the FD. A mached set of vintage Suntour, simplex steel or even Shimano DR's would be a cheaper and likely better solution for this bike.

As for touching up a few spots, maybe try the ol' nail polish trick? Do a search on this forum for instructions.