I have a 1985 Trek 720. Considered by many to be one of the finest production touring bikes of all time. I've made a few changes here and there- Phil Wood/Super Champion wheels, Shimano 600 slotted brake levers, Mathauser brake shoes... and it came with a Sachs/Huret DuoPar rear derailleur. While that unit shifted REALLY nicely- I didn't trust it- so I've been running a beautiful, and badass Suntour XC Pro. It's a great derailleur, it looks really cool, it feels "quality" and it shifts impeccably. Most ordinary people would just keep running that and it would still be sufficiently awesome.

But I've got a bug to swap some stuff around on that bike; and I'd like some help making that decision... I'll be using Suntour barcons for the time being- so with friction shifting- that pretty much allows me to use whatever derailleur I choose to...

I've got a Suntour LeTech that's in really nice shape. This came on the 1984 Schwinn Voyageur SP- and it shifted fantastically on that bike. I wanted to change stuff around on that bike... and swapped it out for an XC Pro (are you sensing a theme?). Anyway, the LeTech is a triple pivot derailleur- it moves in and out- like every derailleur- the cage pivots around- but what makes the LeTech unique is that the cage pivot is on a pivot. This allows the upper pulley to get close to the smaller cogs and back off the larger cogs. It's sort of the same idea behind the DuoPar- but executed much more... excellently. It looks like a rear derailleur should- it has tons of chain wrap capacity and it can take a HUGE rear cog. The super modern computer font screening kind of seals the deal.






I've also got a Shimano M735 Deore XT rear derailleur. This is truly a great rear derailleur. It looks sufficiently badass and it's bullet and bomb proof. It shifts great, it has great capacity for cog size and chain wrap. The Deore XT is really the standard that all MTB and touring bike components are measured against.




Of course, there's also the Suntour XC Pro. IMO the finest RD evAr. It looks perfect- the Suntour branding stands out on the back plate, the springs on the unit are strong and it shifts with authority. Everything about the XC Pro just exudes class and quality. I really love these RDs.




I'd also consider putting the DuoPar Titanium back on. It's a really nifty looking unit- it's the poster child for ultra smooth shifting - it shifted so smoothly, I seriously wouldn't know that the shift went through until I felt the resistance on the pedals.

First World Problem; Bike-Nerd Edition.

Agreed.

Go full XT for the win.

Have you considered Shimano?

I said XC Pro. It looks really great and has a slight edge over the XT in the rare-cool department, plus as you said it's insanely reliable. Now show us a pic of the whole machine!
Signed,
A Vintage Trek Fan

There's no bad answer between th xc pro and Xt. I've never used the le tech, but I vote no because it's called le tech. I did NOT like the duopar at all.

Go Campy or go home.



Or is it, "Go Campy and call home when it shifts into your spokes"?

None of the above. Suntour VGT Luxe

XC vote here.

Great choice, but is it really any better than the other SunTour options?

Here it is last weekend- I was ecstatic about getting out and about on the bike!

Based on looks, XC Pro then the XT. The Le Tech kind of looks odd, but could lead to some interesting conversations? The DuoPar looks pretty fugly in my opinion, that is pretty much worthless anyway. You could just get them all set up for the bike and play pick a RD every time you take her out?

The Le Tech is just so uber-80s that I've got to put a vote in for that one.
You can ride around singing Mr Roboto.
Domo.
Domo.

I don't know...maybe I'm too much of an old school guy. Seems to me C&V means that there was a reason why certain parts/bIkes were put together the way they were and that this part of the draw/aesthetic.

Duopar unless it proves to be unreliable crap...but then again it's just a bike...whatever floats your boat! (Duopar on my 720, but you know, there are times it pisses me off.....hence the charm!)

Le Tech...just because it is odd looking!

My last build, I went from a
Suntour honor,
to a Vx,
to a VGT Lux
to a Cyclone,
before I even finished the build.

DOS 2.1 'low Tech' gets my vote. Looks like a beaut too! Floating lower jockey on it? I forget which Suntour (Superbe Pro short cage or Le Tech) but years ago thought it would be cool swapping to Bullseye. Don't do it!

So this is where all the great Suntour stuff went. Look at post 16...lol

Leave well enough alone and don't go to the effort of switching things if you've got something functional (if only I could take my own advice).

[MENTION=174646]The Golden Boy[/MENTION] - that Trek is a classic build, in that all the parts are selected on merit, not just because they are part of a manufacturer's group.

Do you have a Rohloff equipped bike? This might be the time for that!

What's the spacing on those Rhm?

And that's really how these bikes were specced- the parts were selected by someone for specific reasons. It was an "eclectic mix" of parts from whatever manufacturer made the best part. At that time, the XT brakes were the best ever, to that point- so they got paired with the finest Gran Compe levers of the time (of course, I had to be all neurotic and replace those with some Shimano 600 levers- and am contemplating some slotted Dura Ace levers). The DuoPar was the one of the most wide ranged and smoothest shifting derailleur- to this day, the Suntour Barcons are considered among the best touring components.

I'm not sure what prompted the selection of the Sugino LP crankset or the Simplex Super LJ front derailleur. I don't know that there's any better crankset- but the Sugino AT is an "all time" greatest candidate. The Simplex FD doesn't seem to be as nicely finished as most of the Suntour and Shimano options. I haven't replaced the FD just because it's original, it works well, and it provides that French classicness. I really want to use a Mountech FD on there- my Mountech on my Voyageur SP works nicely- it looks really nice and it's easy to adjust. It appears to have been the top of the line triple FD of its time. I was really surprised with how incredibly light it is. It's just a little heavier than a 1st gen Cyclone- and way lighter than an XC Pro.

I did a bit of thinking about this- at first I was all like "no way, Ray- part of the fun of old bikes are the fun shiney bits"

Then I was all like- "wow, those hubs sound pretty awesomely incredible"

So now I'm all like- "that's really something to consider- if not for the 720, maybe for something else, and maybe not a vintage bike... right now, an internally geared hub is not a part of of my wheelhouse- but the more I think about it, I'm not opposed to it.

Didn't these come with a total capacity of 28t and max cog of 30t?

Pretty limiting, from what ive read. Love the look though. I have one, haven't used it though.

My Favorite Touring Bike RD is The Campag MTB Euclid. I scored a few on close-out in the 80's