ToniH. 

If you would have to pick one rear derailleur model for the rest of your life what would you choose? Lets not think about the cost or how hard it would be source, just what would be your favourite if there would not be any real world limitations.

How about front derailleur?

Charles Wahl

Well, I think that from a vintage point of view (friction) it's just about impossible to beat the Suntour Cyclone, 1st generation -- either the short or long cage version.
I'm no indexing expert, but the Shimano RD-M739 (Deore XT) was very classy looking, and functional, plus it will deal with a lot of teeth and big cogs.

There are a lot of front derailleurs that can work; it's a much simpler operation. So choose based on looks alone.

iab

Tullio's best innovation, the Gran Sport.

nlerner

For friction, Shimano Deerhead (RD M700). For index, Shimano Dura Ace (RD7402)

embankmentlb

Dura Ace 7700gs rear. 9 speed, shiny, down tube or STI compatible, can accommodate large cogs with an extender.

Not near as happy with the 7700 front, it can be a pain to get set correctly. Although, that could be mostly the shifters fault.

seypat

Friction:
This, but all generations. I think the first gen was lighter than the Superbe. The FD will shift a triple as well. For FDs, I haven't tried a Suntour that wouldn't shift a triple.(haven't tried a Superbe, though) Suntour X-1 would be the choice for monster range, and can be found for cheap. Same for the Mountech. A Shimano FD-620whatever will shift a triple also.

Indexed:
Can't put DA7400 series RDs at the top because some of them only work with the corresponding shifters. Orphans from the rest of the Shimano components. If something breaks you are SOL until you locate a spare. Otherwise, plenty of good ones to chose from. Whatever you think looks best.

52telecaster

Friction is all I do but first gen cyclone is my fav. Vx is more common and darn near as good. Always want them in long cage.

Ross200

RD-M900 SGS. or XC Pro

XC Pro FD

Chombi1 

Suntour Cyclone Mk Ii......
One of the best shifting derailleurs I ever used......
Looks really nice plus quite a weight weenie too!

TugaDude

For friction I'd have to side with Suntour Cyclone 1st generation. It is eye candy too with the black knuckles version. To me it is one of the prettiest ever.



For a front derailer, I don't really have a favorite. So let's just go with one that matches the rear derailer.


The last one I'd choose is the Suntour Spirt, because you have to spell it for folks to understand what you are saying.

Moe Zhoost

Huret Duo-Par Titanium. Shifts like a dream.

cudak888 

Sturmey-Archer FW

Jokes aside, I'm a retrogrouch and would second iab's selection of the original Gran Sport. Bulletproof, well mannered (relatively speaking to its design) on corncobs, and beautiful. It is not a modern derailer, but life is too short for boring groupsets.

Plus, most of them had adjuster barrels, a feature unceremoniously dropped on the fabled Nuovo Record.

-Kurt

scarlson 

Shimano XTR M952, long cage.


For friction or indexed, it works great. Got a nice light action, so it works with Simplex levers. Can probably work with bigger than 34t cogs using one of those drop-down link things. Reasonably svelte at 210g or so. Sealed ball bearing pulleys - even the centeron pulley has ball bearings in it, which slide side to side. Brilliant mech.

I have one on my Trek (shifted by retrofriction barcon), on my Colin Laing tandem (shifted by Shimano indexed for 9), and on my Ron Cooper (shifted by Suntour levers).

Classtime 

Huret Jubile for friction. I never pushed them far regarding a wide spread of cogs but on the three beat up Grand Jubile I've had, the derailleurs were lovely. For the front, I'd choose Shimano 600. It seems to require the least trimming.
If my only bike is a Peugeot, Simplex Criterium 1/2 step set up is perfection.

repechage

I am a Stylist, Nuovo Record - when I became aware of that in early 1970, just was the style and quality statement.
the leader of the pack.

stardognine

True, and with the earlier RD-M735, ya get the cool gold letters.😎

I'm not sure which years had that, if others, might have to read up again. 🤔

tricky 

Came here to say the XT or XTR derailleurs but they've already been mentioned!

Kabuki12

Gosh, that’s a tough one . Hmmm… I’d have to say I have Camp. NR on almost all my bikes , a couple with SR. I also like the first generation Cyclone, they are (to me) the best performing RD. I have one with the black knuckles like TugaDude’s with a long cage that I have yet to mount on my Motobecane that presently has a NR . I guess I won’t be able to choose just one !

scarlson 

Oh, and for a front, since the OP asked that too:

Suntour Mountech. Nice straight cage, easy to take apart and put back together, huge chainring capacity.

jdawginsc 

I’ll go cheap. Suntour ARX rear, ArX front and the same for shifters.

Never missed a shift and nearly bullet proof...

Dura Ace 7400 is sublime though...friction or click.

smd4

Dura Ace 7700 25th Anniversary version. Stainless pivots, titanium bolts. Polished to perfection.

bwilli88 

​​​​i chose a Shimano Dura-ace 7700gs. Second, but never tried one, would be a long cage Huret Jubilee.

AdventureManCO 

My practical side says old school XT.

But my visionary side says Suntour Cyclone Mk II (especially if the tension spring was guaranteed to never break).

That derailleur is functionally awesome and with some modification will easily get to and possibly surpass Jubilee weight territory.

kunsunoke 

Dura Ace 7700 GS, for all the reasons already stated.

randyjawa 

This is, without a doubt, the best working rear derailleur that I have ever used. For a bike that I like to ride and ride a lot, this would be my choice...



On the other hand, if function is put into second place and esthetics placed first, I would, without doubt, choose the Shimano 600 Arabesque (I would prefer the long cage version but don't have an easy to access picture of one)...