it's a hell of a drug

The OP could not be more wrong, in my opinion! To that add the fact is that they are no longer produced and that is saying something also.

Yes, they work just fine but the failure rate is very high and can be catastrophic when failure does occur. Wait until one feeds itself into the rings, damaging both the useless derailleur and the ring set...
http://www.mytenspeeds.com/My_TenSpe...rank_Teeth.jpg

http://www.mytenspeeds.com/My_TenSpe..._Cracked_1.jpg


Have a look at Dupont Delrin & Simplex, if you want to know a bit more about what I have learned over the years about these derailleurs.

Randy - I don't think anyone here - including the OP, would contest the fact that the fronts are crap. I think that some of us are saying that the rears are pretty decent derailleurs.

The main issue with the rear derailleurs is those darned pulleys. Here is an example: The pulleys were "slightly" worn (but incredibly still operating) and the body, et al, was perfectly intact. . .
http://i254.photobucket.com/albums/h...w/DSCF0004.jpg

Good comments in this thread about the Suntour V GT - I try to keep one or two always on hand simply because they keep on working and working and working. Although I've seen a pretty fair number of cracked and Prestige RDs, I've never had one actually break on me - and I rather like the way they shift on a five speed rear. On the other hand, I have had the Delrin crack and snap under under riding torque on a Simplex FD. No harm done other than the soiling of my britches because it scared the living hell out of me.

The Op did not differentiate between front and rear derailleurs. I, too, really like the shifting qualities of the Simplex derailleur, but their failure rate is very high. I also offered pictures of front derailleurs, only, as evidence of the kind of failure that I am talking about.

In all fairness to your comment, though, I have never seen a rear Simplex derailleur fail and, once again, they work just fine.

Indeed. Back in the day anyone who replaced a Prestige with a VGT-Luxe or VT-Luxe or whatever noticed an immediate improvement in shifting.

One reason there are so many surviving Prestige rears is that there were so many of them in the first place. Bikes that barely ever got ridden probably account for the survivors. They did work well when new and didn't wear out all that quickly, but too many of them failed catastrophically, which is no fun at all. A cheesy metal derailleur has its own problems, but unless you drop the bike on it or send it into the spokes it will probably not break in use.

Ahh a bit of french bashing! The main reason why I don't post here regularly anymore.

If your going to replace the simplex deraileur on your all original px10 I believe you are missing out on the fun part of owning a vintage bike. Accept the good and bad points of your old bike and having to look after your parts. Dont' slam shift across all 5 gears at once, don't oven tighten the front mech. If the 40 year old part is past its best, find a better condition replacement.

The Simplex Prestige may not be in the top 10 best derailleurs of all time, but if its original to the bike then I'l use it. If Anquetil
could win the tour de france with them, then they are noble enough for me to use.

simplex makes me (insert feeling sick happy face here (surprisingly this forum doesn't have one))

Anquetil only needed the derailleur to last about three weeks. It couldn't wear out, didn't get brittle and it got checked over, cleaned & maybe even lubed every single day.
No reason not to use one on a vintage bike, but unreliability is a good argument against depending on one for touring or high mileage bikes.

vvup, I give up a lot of practicality to own old stuff. Sometimes it's out of sentimentality. Sometimes it's out of frugality. But sometimes, I replace the old stuff with new stuff, because it just makes sense. I'm going to bet you don't ride 40 year old bikes with 40 year old tires.

I looked through this whole thread and see not one instance of French bashing. Wishful thinking on your part?

You ride 40 year old tires, Noglider? :eek:

;)

http://i.imgur.com/ctRKM.jpg

Plastic simplex on ventoux, for the second time that day.

http://i.imgur.com/30qor.jpg

something old. 40 year old tyres I agree are not so practical to ride on. You are right, my bikes do roll on new tyres. I do have NOS tubular's but due to my finaical situation I prefer to keep them nos so that I can sell them or use them in photos.

My original Nomade had one. This RD truly had a mind of its own. Apply a little torque and it may stay in the same cog, but apply more torque (say, to get through an intersection with no time to shift) and it immediately upshifts to the smaller cog. Hated all those unintentional upshifts. Next bike had the SunTour VGT Luxe RD which was worlds better.

vvup - You are not the only one here running a few (front and rear) Simplex DRs. . . I do too, for the reasons you cite. However, I check that front DR for incipient cracks every time, and I advise others to REPLACE their front derailleur with something made from metal. It's the more prudent thing to do.

One way to keep them from breaking, is to not use them. ;)
http://i1227.photobucket.com/albums/.../Gitane108.jpg

I double dawg dare ya!

http://i254.photobucket.com/albums/h.../SimplexFD.jpg

Heck, we can "bash" the Italians too!......all those Ofmega Mistral derailleurs must be getting quite crisp by now too...:rolleyes:...Maybe the pink ones would last longer as I suspect that they would reflect the UV light more than the black ones would......:rolleyes:

Chombi

Oh Yeah! Oh yeah! ...
Wonderful pic, Auchen'. Always been one of my favorite logos. Admittedly, the Record parts on the Gitane was just for fun.
It shifted just as well with those crappy plastic derailleurs on it. ;) Maybe better !

It is a little easier for me to find them, but in 10 or 20 years time when my supply runs out what will I do then? I love to build bike up as they were in the catalog, but if I am building a bike up just for fun I will use a Simplex Prestige, but I have to admit a simplex front derailleur doesn't make the cut.

In defense of the Simplex front derailers, they shift well as long has they don't have to deal with too big a jump and are set up correctly. Maybe they won't crack so readily if they're not over tightened. I'm forced to use one one on my Jeunet because it's the only FD that will work with the Simplex chain guard. It's the fancier one with the chrome clamp and aluminum plug, but the plastic body is the same as the common Prestige. It shifts just fine.

OK, now I feel more confident, about NOT tracking down a Simplex FD, unless I can find one that's all metal, like auchencrow posted. ;) FYI, the Prestige RD I have came on a '74 Atala Giro d'Italia, along with a Shimano FE on the front. I don't recall ever seeing an FE before, but it looks pretty decent. But it is fairly heavy, so I'd have no qualms about throwing a 105 on in it's place. It would be lighter, probably work better, and look better, I think. But I'd have to track down a 105 FD, with that yellow script, since they didn't do red, to match the Simplex in the rear. :D ;)

Mainly I am commenting on the rear derailleur. I've been around cycling for a while and still haven't seen a broken one. Fronts yes. In my opinion the prestige is a fine derailleur. I've had them on a couple UO-8's, and presently on a Super Course and the long cage version on my Grand Sport. They also are equipped with Simplex front derailleurs.

I stand by the Simplex Prestige and believe if maintained and adjusted properly will operate for a long period of time(40 plus yrs. and counting).
And that last sentence contains the key to why I think the Prestige has this myth attached to it, adjusted properly.
In the Boom years the number of bikes that were equipped with these derailleurs was staggering. Almost every entry level bike was equipped with these derailleurs. French, Italian, English, Belgian, you name it the Simplex Prestige was THE derailleur. And perhaps the shear quantity produced lead to the myth. By that I mean, if virtually every bike had them, then any derailleur failure was a Simplex. In my 40 years of cycling I have bent two Campy NR derailleurs. Is the Nouvo record derailleur faulty? No, its because for so many years thats the only derailleur I used.
And out of all those bikes equipped with Prestige derailleurs how many were maintained properly? How many were adjusted properly right out the doors of the local bike shop? In the Boom years the average bike shop employed mainly teenage kids. Building bikes that when shipped from France or wherever were a pile of parts in a box. These "mechanics" assembled bikes as fast as they could to meet the demand of the consumer. The lowly Simplex derailleur rarely was adjusted properly, rarely came back for the 30 day check up, and had a good chance of being shifted into the spokes of the rear wheel within its first summers use.
"I guess those Simplex Prestige derailleurs are junk". "They explode when you shift them". "They crack if you look at them".
All Fallacy!
If anything they were an inexpensive throwaway part, that when replaced, cyclists were finally informed of how to shift properly. And were given a new SunTour GT that was adjusted properly.

I still can't believe how over tightened every nut and bolt is on the bikes I buy. The French have a lighter hand. Afterall its a bike, not a 4 x 4.