Conversion kit for 1980s Simplex derailleur
 

I recently bought a 1983 Peugeot P19 mixte and was abruptly and unceremoniously introduced to the world of Simplex derailleurs. Being a grad student on a tight budget I played amateur bike mechanic and spent 2 hours trying to figure out what was causing the weird clicking sound, like the chain was catching on something in the derailleur. After standing behind the rear wheel I suddenly saw it--3 missing teeth on the plastic jockey wheel like a rat had gnawed it off. Yikes!

Luckily for my student budget there's a bunch of YouTube videos on how to replace the gears in a derailleur. I was looking at a vintage derailleur conversion kit on eBay:

https://goo.gl/pvW8HR

Would this kit work for a Simplex SX610T derailleur?

The bike came with a claw derailleur right? Just pick up something cheap from your local bike coop. $5 and you're good.

You're talking about this bike, right?

http://www.bikeboompeugeot.com/Broch...hure%20P18.jpg

Pretty much any rear derailleur with a claw will work. They're available and cheap.

Now if you're talking about a bike with a forged simplex rear drop out, then finding a RD just became a lot harder.

Yep, that's the bike and it looks like a claw derailleur.

Thanks, great to know that just about any claw derailleur would work if needed. Right now I'd like to keep as much of the original parts as possible in order to have the option of selling it in the future. So probably will either buy another Simplex or try to change out the jockey wheel myself if I can. It doesn't seem overly complicated according to YouTube and definitely cheaper than buying a new Simplex derailleur.

Does anyone know a good guide to changing jockey wheels?

On this level of a bike, the make of the rear derailleur will have zero impact on the value of the bike.

Actually, anyone who knows bicycles would probably change out a simplex derailleur for something else. The best vintage derailleurs were made by Suntour. look for a Vx rear deraileur and any suntour front and they will shift much better. Start going to bike swap meets and you will find all kinds of stuff cheap. Find a bike coop and you will find parts and help learning how to fix your own bike for free.

I would just buy a low-end shimano derailleur. There are some that sell for under $10. BITD, we replaced a lot of Simplex derailleurs with Shimano Eagle derailleurs.

I'm with the other guys above. Replace the derailleur. Using a non-original derailleur, even a non-French one, won't hurt the value of the bike. If you want to stay period-correct, SunTour made some great derailleurs; a SunTour V or 7 would be an appropriate replacement and would likely work better than the original. They're easy to find on eBay and shouldn't cost any more than the replacement pulley kit you posted above. A Shimano Light Action derailleur would be another option that's almost period correct and wouldn't look out of character.

Thanks for all the feedback! Wow, it doesn't sound like Simplex derailleurs are very reliable. Darn, I just ordered a Suntour replacement pulley wheel set yesterday. How bad is the Simplex? Is the shifting really awful? What makes Suntours better than the Simplex?

I'm checking out a local bike co-op tomorrow to see if I can pick up some cheap parts!

.
...in terms of actual shifting performance, they're not as good as the slant parallelogram Suntour, but roughly about as good as every other contemporary mechanism. The real issue is durability, and the amount of Delrin plastic in whichever one you're talking about.

They made a lot of them, in different models over the years. Some were more durable than others. The plastic does not age well.

For my money any suntour derailleur is better than the Shimano eagle. The Eagle is heavy and out dated tech. Suntour made some of the best non indexing derailleurs ever. I have at least one of each model or have used them . The Vx is one of the best. Light , strong, good looking and very durable. Get a nice one and you can't go wrong. I also like the BL They are even lighter but probably harder to find.

Jonny

Not all Simplex rear derailleurs are unreliable, and all of them work quite nicely when new. But Simplex was fond of Delrin plastic, and many of their low-end derailleurs used Delrin in the parallelogram body. Grit eventually erodes the pivots and makes the derailleur action sloppy. But there are Simplex derailleurs with all-metal bodies as well, and these are more durable than the Delrin models.

No. When new, they work quite well. The upper and lower pivots are both sprung, which allows the pulley cage to track the cogs well. Shimano copied this design for their derailleurs as well. SunTour's design fame came from their patented "slant parallelogram," which mounted the parallelogram on a slant with a nearly horizontal alignment. This followed the cogs even better than the double-sprung pivots. It's interesting to note that when SunTour's patent expired, Shimano quickly incorporated the slant parallelogram into their own derailleurs, and almost all modern derailleurs have both double sprung pivots and a slant parallelogram.

fireroadie-


Your alloy Simplex will shift quite well with new jockey wheels especially with a clean chain and a good freewheel. Change the wheels and carry on. I have used a 410 GT for years and it is very good.

Great to hear this! I finally got the replacement jockey wheels in the mail and removed the old wheels. The previous plastic wheels were so badly chewed up it look like mice gnawed off half the teeth on them. I was able to replace the wheels after watching a YouTube video for replacing jockey wheels from Global Cycling Network. The only tough part was aligning the screws with the wheels and washers and getting the back cage plate to screw on correctly while using the allen key to twist the cage outward so I can reach the wheels. There's probably an easier way to do it, but my noob techniques prevailed and everything took only 1/2 hour!

I haven't tested out the Simplex SX610 yet. Still waiting for some Panaracer Pasela tires to arrive in the mail. Once they get here I'll post about how the Simplex compares. The only other friction derailleur I've ever used was a Shimano Titilist, so will compare it to that.

Simplex Suntour Jockey Wheel Replacement Kit
 

Lovecitycycles has this conversion kit available on ebay and on our website. The kit will fit most Simplex and vintage Suntour rear derailleurs using the 6 mm mounting bolt. Kits are also available with sealed bearing jockey wheels We also have several other hard to find replacement part for your vintage road bike : rear drop out spacers, Simplex skewer wingnuts...and others

As a former grad student, I must point out that whatever you end up needs to look cheaper and less roadworthy than any of the undergraduate bikes, even if the difference is only cosmetic. It's a matter of pride and honor. ;)

This is the kit I bought and I had left you guys a high rating on eBay. The kit is fantastic! My Simplex SX runs beautifully (after an expert mechanic tuned it up some more). Installation was easy after watching the YouTube video. Thanks for making this! It's kept my bike in all-original condition and works great in all sorts of weather conditions!

The slant is here to stay, but SRAM's upper pivots aren't sprung; they just sit against the B-screw. And Shimano's Shadow derailers have skipped the upper spring too; they work like SRAM.

With the Shadow design taking over (it's on R9100 and R8000), it looks like the sprung upper pivot's days are numbered. Wonder if Campy will follow suit one day...

You don't need the pulleys to hug the cassette if you're friction shifting.

Shimano's B pivot spring was something they came up with when Suntours slant patent was in effect and decided to keep - but it is not necessary to keep the pulley close to the cassette.

Welcome to the forum, Lovecitycycles! For the regular members, I've bought a number of items from Lovecitycycles, and they're an excellent source. Good prices, they've quickly answered any questions I've had, and excellent shipping speed. Everything I've bought from them was near-NOS. Highly recommend them.

Simplex Suntour Jockey Wheels
 

thanks for the kudos everyone...We try hard ....been selling vintage parts on ebay for 9 years. Get new items every week..have lots of small parts not listed on ebay....so if you can't find it....drop me a note. Adding this week "new" replacement stem caps for those Cinelli Grammo stems.....had them made here in Loveland, CO

The classic, period correct replacement for a Delrin Simplex derailleur is a Suntour VGT. I Googled it just today and got a host of hits.