The 'which derailleur will work with my stuff' game
 

My tourer is a hodgepodge of parts. On the drive train alone:

- Dura Ace 9 speed index bar end shifters
- 105 front derailleur, FD5504
- Tiagra rear derailleur, RD4400
- Sugino 48/36/24 crank
- SRAM chain
- Ultegra 9 speed 11~28 rear cassette

Don't get me wrong, it works and I'm not complaining (well, maybe that rear derailleur, it is certainly stretching beyond what Shimano ever intended). The thing is, the cheap pedals I got are driving me nuts so I'm shopping for a set of Dura Ace 7400 aero pedals to replace them with. This will make two components on the bike that are of the same brand and line, so I figure I could keep an eye to upgrade other parts of my drive train to Dura Ace. Why? Because old dura ace stuff is cheap, plus it would get me that warm and fuzzy feeling that only Dura Ace can provide :D

Which Dura Ace front and back derailleurs would be able to wrap around a 48/36/24 triple with a 11/28 cassette? It doesn't need to be pretty, I have ridden a suicide setup before (where big front/big back is not only not advisable, but an impossibility that could lead to an explosion of parts) :innocent:

Your asking the rear derailleur to wrap 41T which no Dura Ace was ever designed to come close to. The current 7900 is rated for 33T so you way out of it's league. Even giving up the smallest 7 cogs when in the granny and using the 21T as the smallest will barely make it.

There was a Dura-Ace 9-speed long cage triple rear derailleur, 7703. I think it was rated for 38t capacity. If you could find one you could probably make it work. Might have to use a 26 granny ring on the crankset. Try searching e-bay and other web sites.

Same thing with the Tiagra I'm currently abusing :D

I looked it up and the triple rear can wrap around 37t, same as the tiagra. That doesn't mean that it would work but it may be close enough, and I'm certain that it would work with a 26t granny. The only problem is that while the front triple is rather inexpensive, it looks like people want real money for those long cage DA rears.

I'll keep an eye out in case I see one for a reasonable price. Right now the only thing that really needs upgrading are the cheap pedals.

think Deore, not Dura Ace..

The bad thing about DA is the fact that they experiment with it. If it doesn't work it goes away for a new and improved part. The octa-link DA BB and 10sp hub with an Aluminum freehub body are prime examples. Throw in the eliptical bio-pace ,rings while your at it.

The Shimano bar end shifters are the only shifter in the Shimano line up that will work w/road or mountain rear derailleurs.
Thus to work w/the gearing you want you can go with Deore, Deore LX, Deore SLX, Deore XT or if you are feeling rich, XTR.
I would recommend a non shadow rear derailleur as they still have a barrell adjuster on them. Either low normal [ Rapid Rise ] or tradittional will work.

You would have no trouble finding a touring long cage ultegra RD. Used they should be cheap. Untill WiFli realy catches on some of those parts should stay cheap. When wide gearing with compacts does catch on, then these parts are going to be hard to get and expensive.

Long cage Shimano road derailleurs take a 27/28 tooth large cog [ low gear ]. Their chain wrap capacity is usually 38 or 39 teeth.
Long cage Shimano mtn derailleurs take a 32/34 tooth large gog [ low gear ]. Their chain wrap capacity is 41 or 43 teeth.
A mountain derailleur allows him to gear lower or wider if he wants to w/o any compatibility issues.

No, that's not true. Except for 8 speed and earlier Dura Ace, and the newest "Dyna Sys" 10 speed mountain bike group(s), all Shimano indexed rear shifters and index-compatible rear derailleurs, whether from "road" or "mountain" groups, are designed with the same cable pull ratio, and are perfectly compatible with each other.

You could take a current 10 speed Ultegra rear road shifter, for example, and use it with a mid-90's Deore rear derailleur, and the two parts would work just fine together.

You guys are right, the Deore is a better fit. I will keep an eye for one at the right price to replace my abused Tiagra one.

There are three long cage models on the current line:

RD-M770-SGS Shifting: Low, normal
RD-M771-SGS Shifting: Top, normal
RD-M772-SGS Shifting: Top, normal, shadow

I understand that the shadow version is designed so it doesn't stick out as much. For my intended purpose, does it matter which of the three long cage models I get? Is there a significant difference between the above ones and the previous version?

Of those three, I suggest the RD M771, which is a conventional (top normal) derailleur. You don't need the "Shadow" version. Those 7xx series derailleurs in your list are Shimano Deore XT derailleurs, not Deore. The Deore series would work fine, too, and cost quite a bit less. Again, just go with a "top normal" version, and no need to go with a Shadow version.

Shimano Deore LX RD M581
This is a long cage model that is cheaper and performs just as well.

Unless your are using antique or very basic Shimano rear derailleurs the shifter will always determine what you can use and how reliable it will be.
The issue when crossing road and mountain groups is set up. It's doable, it just takes a lil more tlc than directly compatible components.
For those who do their own work, not an issue.
For those who pay others, like the mechanics at their LBS, they need to stick to the like groups as spec'd. Being a mechanic in a LBS means you try to dot I's and cross T's and make sure you go with what you know will work as it's on someone else's dime. So you stick to the manufacturers specs.
Abdon, I guess the question I should have asked you is whose during the work, you or someone else? I assumed that someone else was when I was reading your questions.
As far as the derailleurs go, think of it this way: on a top normal derailleur if your cable tension was too slack, your shifts to lower or easier gears would be slower/less precise. On a low normal, a slack derailleur cable would result in slower/less precise upshifts to larger/harder gears. In either case, the barrell adjusted makes minor adjustments better, so stay away from the shadow models.
If you can find a LX, buy it, as they are solid.