# Dura Ace RD-7700 and RD-7800



## TunicaTrails (Jun 29, 2009)

Here's my drivetrain setup. Before I tell you, let me say that I race and I ride my bike a lot, in both XC and marathon races. What I use has to be reliable and work well.

I have found that using short cage Shimano Dura-Ace derailleurs, both front and rear, works wonderfully for my setup with 8-speed shifters and cassette. I have two chainrings up front.

Listed weights:

Shimano Dura-Ace RD-7700 rear derailleur: 195 grams 
Shimano Dura-Ace FD-7800 front derailleur: 74 grams
SRAM PG850 11-30 cassette: 220g
SRAM Attack 8-speed grip shifters: 187g/pair


































For me, it's both light and inexpensive. I was using 11-32 cassettes with no issues in many races before, other than a little bit of noise in the big cog. It shifts smoothly and quickly, better than any other rear derailleur I've used (those being: X.0 short and long cage, X.9, XTR, LX, Sora short and long cage)

Feel free to let me know what you think, :thumbsup: or ut: I've been thinking about a 1x10 SRAM setup, 11-36 with 34t up front, but I do enjoy what I've got now.


----------



## nino (Jan 13, 2004)

My words!

Except that using the newer 7900 parts saves you even more weight.

I've been using DA front and rear for over 10 years now. To use a 32 cassette you need to change at least the standard upper 11t pulley to 10t but that's really all that's needed to make it run even on a 32 cassette. The short cage makes for more precise shifts, less chance to get caught on the trails or in crashes and less play in the cage since there is less leverage...super precise shifts! My front shifts with the Speen adapter are faster than XTR.

Shown below:
Dura Ace 7900 rear derailleur standard: 165g
DA 7900 with decent tuning (10t pulleys and aluminium bolts): 143g

DA 7900 braze-on derailleur with Carbon clamp: 66g
DA 7900 with integrated 34,9 clamp and aluminium bolts: 74g
DA 7900 with intgerated clamp + Speen Top-Pull adapter: 79g

11-30 titanium cassette: 157g

9s shifters: 94g

PS: using a 1x10 setup with a high gear of 34/11 would definitely not be fast enough for me. I'm currently using 27-40 up front and 11-32 on the cassette and my high gear of 40/11 is just what i need. In very few occasions i could need 1-2 teeth more on the front but most of the time i'm just fine but going even lower on the front ring i would feel like i would be missing top speed - definitely.


----------



## xcatax (Mar 26, 2009)

Now im running 

Sram x0 ss tuned: 166 grams 
Sram red + speen + btp 80 grams
Recon ti 11-30 : 167g
SRAM x0 twister: 195g/pair
Chainrings 38/26

Saves 1x10 for me 136g --- 520e <--------- :nono: 
1xtwister -95g
1xrecon gripshift -49g 60e
front mech 80-30 (chain guide) -50g 50e
rear mech long cage +30g 120e
longer chain +10g 40e
1x26 ring + bolts -23g
sram xx 11-36 208-167= +41g 250e

Thinks il keep going 2x9 :thumbsup:


----------



## TunicaTrails (Jun 29, 2009)

Thanks for the replies. I think the DA RD-7700 actually runs about 180 grams; I need to throw all this stuff on a scale. Right now the older models of Dura-Ace are much cheaper, and I've mangled a couple of rear derailleurs this year. I'd be crying if I hadn't spent less than 100 bucks on them  

I find that 8-speed shifts more reliably than Shimano 9-speed. Low-end SRAM cassettes wear out quickly but again, at 25 bucks or less, I can afford to swap them out when needed. 

I should mention that I'm racing a 29er, so 36x11 is a tall gear, it's my max right now. I agree that 34x11 might be too much of a compromise.


----------



## moab63 (Dec 29, 2003)

*On a related note can you use*

the Ultegra stuff, I have a few front derailleurs. Im running all xo drivetrain. Building my new flash. Trying to reuse some parts at least a few.:thumbsup:


----------



## kiatkiat (Sep 21, 2008)

Hi, does anyone know if 7800 RD outer cage is interchangable with 7700's?

I recently found someone selling carbon outer cage for 7800. Wonder if I can put them on my 7700.


----------



## TigWorld (Feb 8, 2010)

Can the DA 7900 front derailleurs be used (or modified) for a triple chainring front?


----------



## TunicaTrails (Jun 29, 2009)

There are Dura-Ace for triples, but you need a special model of front derailleur, either the FD-7703, FD-7803 or FD-7903.



TigWorld said:


> Can the DA 7900 front derailleurs be used (or modified) for a triple chainring front?


----------



## TigWorld (Feb 8, 2010)

Yeah, but the triples don't seem to be any lighter than a tuned recent model XTR and heavier than an older model XTR.


----------



## Roadsters (Jul 7, 2008)

A few days ago I put a Dura-Ace 7700 cassette and rear derailleur on my 2000 Breezer Lightning, which already had Dura-Ace 7700 175mm cranks.

Gearing is 39 by 12-27. This combination shifts quickly and works great all around.

Fast and fun to ride.


----------



## Eiron (Jul 20, 2010)

Hi, I'm building up a new bike & currently have an older XT short cage rear derailleur shifting perfectly on my 12-28 & 26/36/46 setup. This XT has 10t pulley wheels & the same link & cage lengths as the 105 RD of the same MY. The cage is stamped with 28 Max Capacity & (I think?) 28 Total Capacity.

A friend gave me a Dura Ace RD 7700 that I'd like to use on this drivetrain instead, but the Max/Total listed online for the derailleur is 27 Max & 29 Total. The link lengths appear to measure the same as the XT short cage, & the cage is maybe 2mm or 3mm shorter.

Is anyone here using this RD on a triple? Or know what the outer limits of gear range is for it? And will the larger 11t pulleys give me comparable chain take-up to the slightly longer XT cage?

Thanks

Greg


----------



## satanas (Feb 12, 2005)

It'll probably work much the same, but you may lose 1 or 2 gears on the small ring. Try it and report back!


----------



## nino (Jan 13, 2004)

Eiron said:


> Is anyone here using this RD on a triple? Or know what the outer limits of gear range is for it? And will the larger 11t pulleys give me comparable chain take-up to the slightly longer XT cage?
> 
> Thanks
> 
> Greg


I have used DA derailleurs for years with triple cranksets up front. The only "problem" is the max. tensioning capability of the short cage. Using the standard 44/32/22 will give you a loose chain when using the small 22t up front paired to 11/12/13 on the cassette (which are gears you usually don't use anyway). Using smaller chanrings up front helps. I used 42t as big chainring and had no problems for about 7-8 years. Also important is that you run the shortest possible chain lenght! You need to determine the shortest chain lenght by putting the "big-big" gear in and have the chain shortened so it barely accepts that gear without over-streching the rear derailleur.

The pulleys have nothing to do with taking chain slap. That's determined by the lenght of the cage only.
Smaller pulleys will allow to use the short caged derailleurs with bigger than 28t cogs....like explained in that other thread here:
http://forums.mtbr.com/showthread.php?t=630098

So installing bigger 11t pulleys won't help in thightening the chain at all but it reduces the capability of the short caged DA to be used with real MTB cassettes like 11-32.


----------



## DeeEight (Jan 13, 2004)

Actually the pulleys do affect the total capacity as the larger diameter the pulley, the further apart the effective span of the derailleur cage and thus the capacity of chain it can take up. The GS cage Ultegra 9speed derailleurs had the same actual cage length as the old M900 XTR derailleur, yet the effective span was greater because of the 11T pulleys vs 10T pulleys. The derailleur's rated capacity was 4T higher.


----------



## kiatkiat (Sep 21, 2008)

I had use the stock 7700 rear derailleur with a 11/34T cassette on my commuter bike and it work fine. Able to shift to the largest cog smoothly. BTW, I'm using a 1x9 setup.


----------



## Eiron (Jul 20, 2010)

kiatkiat said:


> I had use the stock 7700 rear derailleur with a 11/34T cassette on my commuter bike and it work fine. Able to shift to the largest cog smoothly. BTW, I'm using a 1x9 setup.


Very interesting. From earlier comments I would've thought that the upper pulley would get pretty chewed up from running against the cog teeth, no? Do you actually have some measurable clearance between pulley & 34 cog teeth? I'm thinking of swapping my 12-28 for a 14-32, so being able to keep the larger diameter top pulley would be a definite plus!

On any of my bikes that I set up with a triple, I try not to run the small ring with the two smallest cogs or the large ring with the two largest cogs. So not having "full range" of all gears is not an issue. Since I plan on spending the majority of my riding time on this bike, I'd really like the shifting to be as intuitive as possible. The DA 7700 seems to be the right direction for that goal.

Once I get it all reconfigured, I'll let you guys know how well it works.


----------



## nino (Jan 13, 2004)

Eiron said:


> Very interesting. From earlier comments I would've thought that the upper pulley would get pretty chewed up from running against the cog teeth, no? Do you actually have some measurable clearance between pulley & 34 cog teeth? I'm thinking of swapping my 12-28 for a 14-32, so being able to keep the larger diameter top pulley would be a definite plus!
> 
> On any of my bikes that I set up with a triple, I try not to run the small ring with the two smallest cogs or the large ring with the two largest cogs. So not having "full range" of all gears is not an issue. Since I plan on spending the majority of my riding time on this bike, I'd really like the shifting to be as intuitive as possible. The DA 7700 seems to be the right direction for that goal.
> 
> Once I get it all reconfigured, I'll let you guys know how well it works.


The guy above with the standard DA on a 34t cassette must have a special, longer than usual derailleur hanger. I have never seen a DA accept a 32t cassette without changing at least the upper pulley to a smaller diameter let alone a 34 cassette!


----------



## kiatkiat (Sep 21, 2008)

nino said:


> The guy above with the standard DA on a 34t cassette must have a special, longer than usual derailleur hanger. I have never seen a DA accept a 32t cassette without changing at least the upper pulley to a smaller diameter let alone a 34 cassette!


Hi Nino, this is not a special derailleur hanger. It is just an old school bolt-on derailleur hanger from the 90s.

And just did a measurement this morning. Its approximate 10mm longer than modern derailleur hanger.

I have another hanger that is riveted to a Tourney RD. That one is even longer. Guess I can use it for future 36t project.


----------



## fastback67 (Apr 6, 2010)

Roadsters said:


>


oooh nice bike (specially the frame). makes me jealous.
does this setup work well without chain guide ?


----------



## nino (Jan 13, 2004)

kiatkiat said:


> Its approximate 10mm longer than modern derailleur hanger.


That's what i thought so your setup is for OLD frames only but todays frames, or frames of let's say the last 10 years won't accept a DA + 34t cassette.


----------



## kiatkiat (Sep 21, 2008)

Think of the brighter side. If able to do some basic maching, or know friends that can do that. It will be easy to make a custom hanger that is 10mm longer.


----------



## morati (Mar 25, 2004)

Where are you guys getting your Shimano compatible 10t upper pulleys from? I can find Campy 10t versions, are they the same?


----------



## DeeEight (Jan 13, 2004)

Tacx and BBB offer some decent ones. Or you could just... wow...order from shimano.


----------



## DeeEight (Jan 13, 2004)

nino said:


> The guy above with the standard DA on a 34t cassette must have a special, longer than usual derailleur hanger. I have never seen a DA accept a 32t cassette without changing at least the upper pulley to a smaller diameter let alone a 34 cassette!


The photo clearly shows what sort of hanger his frame has. The kind all cheap low end steel frames have. And just because you....the great nino... haven't ever seen something doesn't make it untrue. Hard to believe there are cyclists out there who've seen and done more than you isn't it?


----------



## rensho (Mar 8, 2004)

I run a 32 and a 34T using a DA 7700 rr der. Just put the B screw in backwards. I've done this on 4 different frames. Using a 34T is a stretch, but works.


----------



## nino (Jan 13, 2004)

DeeEight said:


> The photo clearly shows what sort of hanger his frame has. The kind all cheap low end steel frames have. And just because you....the great nino... haven't ever seen something doesn't make it untrue. Hard to believe there are cyclists out there who've seen and done more than you isn't it?


ah - i love it when you have to stink around. There's no better dessert


----------



## Eiron (Jul 20, 2010)

rensho said:


> I run a 32 and a 34T using a DA 7700 rr der. Just put the B screw in backwards. I've done this on 4 different frames. Using a 34T is a stretch, but works.


Cool! I never thought of that, thanks! How many chainrings are you running?

Did SanRensho make mtbs? I gave my 3R SR road bike to my son, but he's forsaken it for a beat-to-crap C'dale CAD3 frame.


----------



## TunicaTrails (Jun 29, 2009)

Interesting idea, I'll have to try that. What does putting the B-screw in backwards accomplish? Does having the screw head extended against the derailleur add just a little bit more extension in order to allow 34t?



rensho said:


> I run a 32 and a 34T using a DA 7700 rr der. Just put the B screw in backwards. I've done this on 4 different frames. Using a 34T is a stretch, but works.


----------



## Roadsters (Jul 7, 2008)

fastback67 said:


> Oooh nice bike (specially the frame). Makes me jealous.
> Does this setup work well without a chain guide?


Sure. In all of the fast riding I've done on the Breezer both on the road and on fairly challenging trails, the chain has never come off.


----------



## Eiron (Jul 20, 2010)

OK, I finally got a chance to install this DA RD-7700 on my 12-28 rear & 26/36/46 front setup. So far it works better than the short cage XT RD-M735 SS I've been running.

So my next question is, does anyone know if I can use the XTR FD-M950 on my 26/36/46 ring combo? With the huge offset (drop?) between the front & rear shift plates, it looks like it will hit the middle ring before completing the shift. I can't seem to find any good listing of ring range for this FD.

Thanks again,

Greg


----------



## schnapmaster (Feb 26, 2004)

I've often had success with short cage road derailers with stock pulleys and 11-34 cassettes, without reversing the B set screw. It must depend on what hanger your frame has. Niner EMD9 and AIR9 work. Fisher frames have worked for me as well.


----------



## Eiron (Jul 20, 2010)

Alright, the XTR FD-950 will work with my chainring combo, but won't work with my Ritchey Logic 110/74 crankarms. That is, it shifts fine, but it won't clear the inside of the low-profile crankarm.

So the new question is:
Is anyone running the DA FD-7700 on a triple?


----------



## nino (Jan 13, 2004)

Eiron said:


> Alright, the XTR FD-950 will work with my chainring combo, but won't work with my Ritchey Logic 110/74 crankarms. That is, it shifts fine, but it won't clear the inside of the low-profile crankarm.
> 
> So the new question is:
> Is anyone running the DA FD-7700 on a triple?


i used the FD7700 for years on a triple.no problems.


----------



## satanas (Feb 12, 2005)

You *may* find you can get the M950 to work by bending the rear part of the cage inwards; I have had to do this with all MTB derailleurs used with Ritchey cranks, both 110/74 and 94/58. The road derailleur will clear fine, but no idea how well/badly it might work, however, I suggest you keep the gap between the outer 2 rings to NO MORE THAN 10T at the most.


----------



## Eiron (Jul 20, 2010)

Well, I've been stymied again in my attempt to use one of the high-end FDs I've already got on hand. The new stumbling block is finding a light-but-sturdy braze-on clamp to fit my 28.6mm downtube. I've got both of Shimano's clamps (31.8mm & 34.9mm) & they're reasonbly light for what they are (about 30g-40g, measured on my analog postal scale).

I'd like to use the DA FD because of its design & light weight, but not if the clamp puts the total weight above the Ultegra or XT FDs I've already got. One of the local bike shops has the J&B clamp, but it's way over-designed for a simple clamp & weighs in at over 60g. I'm not interested in paying extra for carbon clamps. I know there are a few more aluminum models available in my size, but nobody publishes weights for these things.

So my official Weight Weenie question is:

Which 28.6 aluminum derailleur clamp is the lightest?


----------

