# How easy is it to use a Dura-Ace Front Derailleur on a mountain bike?



## Mr. IROC-Z (Aug 24, 2006)

Hey Guys,
I just noticed that the weight difference between a new 7900 Dura-Ace and an XTR is almost double (66g vs 120g). I have seen some folks use the Dura-Ace front Derailleur on their bikes. Is it easy to do? I will be using twist-shifters, will it work with them?
Any advice would be appreciated.
Thanks,


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## nino (Jan 13, 2004)

Mr. IROC-Z said:


> Hey Guys,
> I just noticed that the weight difference between a new 7900 Dura-Ace and an XTR is almost double (66g vs 120g). I have seen some folks use the Dura-Ace front Derailleur on their bikes. Is it easy to do? I will be using twist-shifters, will it work with them?
> Any advice would be appreciated.
> Thanks,


Hi,
they mount as easy as any other derailleur.

2 main "problems":
-they are available as DOWN-PULL only. But a Speen adapter from Speen.de converts them to Top-Pull.

-they are supposed to work with 2 chainrings only and on triple setups they might not have enough movement to reach the outer ring. There's 2 ways to solve this: Correct your chainline by installing a shorter BB spindle which brings the rings in...on integrated cranks you can put those spacers you usually have right or left of the BB shell on the left side only which again moves the chainrings to the center of the bike. And finally you can modify the DA derailleur so it swings out farther than usual. the endstops can be modified so it reaches the outer ring (see pic below!).

But for double chainrings up front there is no modification needed!


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## Mr. IROC-Z (Aug 24, 2006)

Nino,
Awesome! Thanks for your help! I have a bottom pull frame so I guess I am set. Happy to be saving another ~50 grams!
Thanks!


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## Thomas Anderson (Mar 10, 2006)

Hmmmm - so 34.9 clamp and triple set up would work on a 2008 Epic? The 08 Epic needs a top swing type FD so I'm not sure whether this would work but I'd be peeing my pants to get a DA7900 FD on my ride


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## nino (Jan 13, 2004)

Thomas Anderson said:


> Hmmmm - so 34.9 clamp and triple set up would work on a 2008 Epic? The 08 Epic needs a top swing type FD so I'm not sure whether this would work but I'd be peeing my pants to get a DA7900 FD on my ride


Well-top swing is different in the height of the clamp to the cage.check that on the pics above so you have an idea if that could fit on your bike BUT i guess they suggest top-swing for a reason...


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## Boralb (Jan 8, 2010)

Is there any compatibility issue for speen adaptor to use with triple version fd like DA7803?(I don't know if there is a triple crankset version of DA7900) I plan using them with 970 xtr crankset..


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## nino (Jan 13, 2004)

Boralb said:


> Is there any compatibility issue for speen adaptor to use with triple version fd like DA7803?(I don't know if there is a triple crankset version of DA7900) I plan using them with 970 xtr crankset..


If i'm right the triple version isn't any lighter so all the advantage you are looking for would be gone. That makes no sense. If you want to play it safe get an older XTR like FD-M950 or FD-M952. Those are around 110g and work as good as any current derailleur too.


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## checky (Jan 13, 2006)

Right,
next is, that the triple racebike FD's have mostly a longer cage as MTB FD have. Result is, that the end of the FD's cage could touch the chainstay.
Had this issue at some different frames with the 7703 (with 44/32/22 setup). I use the Sram RED with self made TP adaptor now. Works fine with Sram twist shifters.


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## Limbo (May 1, 2009)

A quickie qns here..

If $$ not an option, what would you choose, if weight is more important than bling factor? 
- campaqnolo front derailleur ?
- duraAce front derailleur ?

I am referring to braze-on version.


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## checky (Jan 13, 2006)

BTP's copie of the Campa Record with 35g:
http://www.b-t-p.de/B-T-P_Team/Produkte/Antrieb_Schaltung/antrieb_schaltung.html
Dont know how it works.


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## adept1 (Jul 25, 2008)

Another potential problem is interference with the water bottle brazes. I was unable to use Dura-Ace 7900 or SRAM Red on my bike because of this. I guess you could file them down to get around this problem, but I just decided to live with my X.9 front instead.


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## nino (Jan 13, 2004)

adept1 said:


> Another potential problem is interference with the water bottle brazes. I was unable to use Dura-Ace 7900 or SRAM Red on my bike because of this. I guess you could file them down to get around this problem, but I just decided to live with my X.9 front instead.


I had this problem too on my previous Winterbike-frame...to solve it i dremelled some of the clamp.Easy fix!


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## Limbo (May 1, 2009)

Are you offering BTP version as part of the option?

But these are but insanely expensive.:madman:

I have ordered braze-on campaqnolo, and now regretted about it.
Few friends of mine are telling me that DuraAce braze-on are even lighter.
It damn sucks!
Anyway I should be replacing the stock bolt from those from torontocycles.



checky said:


> BTP's copie of the Campa Record with 35g:
> http://www.b-t-p.de/B-T-P_Team/Produkte/Antrieb_Schaltung/antrieb_schaltung.html
> Dont know how it works.


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## JAZ (Apr 22, 2005)

nino said:


> If i'm right the triple version isn't any lighter so all the advantage you are looking for would be gone. That makes no sense. If you want to play it safe get an older XTR like FD-M950 or FD-M952. Those are around 110g and work as good as any current derailleur too.


Well I feel a bit stupid now after buying a 7803 off Ebay to get a light triple FD, my fault for not doing my research better. I'm sure I read on here the 7800 triple ones were what I needed, oh well I'm sure it's lots lighter than the XT one it's going to replace & I'll post a weight when I get it.
I hope it fits without modification as I have a Salsa Bandito, I'll just dremel it like Nino's if not.


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## scant (Jan 5, 2004)

Nino, do you have any more pictures of your front mech modification (to allow use with tripple chainsets) please 

did you need to remove material purely to allow the end stop of the adjustment screw? or to make room for the mech to move further?


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## JAZ (Apr 22, 2005)

The 7803 triple I bought turned out to be 115g (34.9) so not really that light weight, but I saved 20g on my previous FD.


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## Kyle2834 (May 4, 2007)

My FD is 210g. Life could be worse.


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## eric512 (Jan 27, 2006)

Just tried a new 7900 on my Spark with a triple. No go. Even if I drilled it out to reach the outer ring, the chain would not clear the inner 22 ring. Not enough tooth range on that type of cage.

Middle ring worked find though - and very light on a 34.9 clamp.

So to all the WW's, I have a new DA 7900 34.9 clamp for sale. I only paid $89 for it from Performance - on sale. 

PM me if you want it before I return it.


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## nino (Jan 13, 2004)

ERIC512 said:


> Just tried a new 7900 on my Spark with a triple. No go. Even if I drilled it out to reach the outer ring, the chain would not clear the inner 22 ring. Not enough tooth range on that type of cage.
> 
> Middle ring worked find though - and very light on a 34.9 clamp.
> 
> ...


I don't understand "would not clear the 22t..."?
I have seen several triple setups with the 7900 so where's your problem?


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## eric512 (Jan 27, 2006)

nino said:


> I don't understand "would not clear the 22t..."?
> I have seen several triple setups with the 7900 so where's your problem?


Thanks Nino. The chain would drag on the bottom of the cage when on the inner 22 ring. Even when on the larger cogs on the cassette.

I set the height so it was a few mm's above the outside chainring.

Already took it off - so I don't have any pics. I can mount it again in a few days to take a pic. Would be great if it could work.


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## checky (Jan 13, 2006)

That depend on your seatstayangle.
I made the experience, that where the DA not fit because of this issue, the Sram RED will work.


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## Pinokio (Oct 23, 2009)

ERIC512 said:


> The chain would drag on the bottom of the cage when on the inner 22 ring. Even when on the larger cogs on the cassette.
> .


you have full sus? with ht there is not problem at all

clearance at fs is about 4-5cm (maybe more) higher than on ht, so your crank axle.
change 22 to 24 ring it will help a bit


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## Pinokio (Oct 23, 2009)

nino said:


> I I have seen several triple setups with the 7900 so where's your problem?


Spark plus clavicula MTB (triple) plus 7900 will not work.

Outer ring is to far so cage of DA starts to go up instead out and push chain toward big ring.


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## KenDobson (Jan 18, 2008)

Im afraid that the New Speen adaptor with a 7900 dura ace der wont pull enough cable with Sram XX front shifter. The der will move enough but I cant get it to not rub the chain on the sides in two gears, either top or bottom. I can get it to shift fine just need alittle more travel from der. Bummer, so I ordered a XX front der, and the weight that goes with it.


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## pernfilman (May 24, 2007)

You are better off with XX IMO the speen adapter will not be able to take the beating like the XX will. The extra 25 grams is worth the hassle free solid engagement. I found the speen/7900 combo extremely disappointing, been loving the XX since then.


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## ivan_msc (Jun 19, 2009)

*Carbon Ti adapter*

Hi,

Has anyone tried the Carbon Ti adapter? I would like to know how it performs, otherwise I'll be picking the Speen adapter.


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## sergio_pt (Jan 29, 2007)

The speen adapter is cheaper and works so why go for carbon-ti?

I have been playing with a DA 7900 + speen adapter on a XTR triple crankset and XTR shifters. 
It's not the best setup for a MTB... I still have to do the dremeling as nino shows to let the cage move farther way from the frame. Will try that tomorrow. For what I could try it shifts well from inner ring to midle ring and vice versa but it doesn't have enough reach for the outer ring. 
So far I think this setup has more negative points than positives.
Positives: 

It shifts
lighter.
Negatives: 

you have to tweak the FD with the speen umlenker 
and you have to dremel a new part to make it work on triple crankset, 
the *cage is very narrow* and the chain will rub on the sides very easily maybe a narrower 10s chain can make it a little better.
probably not so strong as a MTB FD when shifting under power.

I'll see how it works tomorrow when I complete all the tweaks.


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## nino (Jan 13, 2004)

sergio_pt said:


> [/LIST]Negatives:
> 
> you have to tweak the FD with the speen umlenker
> and you have to dremel a new part to make it work on triple crankset,
> ...


Well- i on the other hand see only positives:
much lighter
shifts better
best use on 2x9 / 2x10 setups where you have less crossed chains than on triple setups (especially Shimano integrated cranks have a bad chainline!)
NO adapter needed at all if you have down-pull on your bike
Not as strong?? What are you doing with your derailleur? How are you shifting? The DA is as strong as others.

SURE you use 10s chains! Why would you use the heavier 9s when the slimmer 10s works as well ?!

IF the reach for triple setups isn't enough why not try the older 9s DA FD-7700. I used that version for years on my triple cranksets and never had to modify anything.But i can't understand why people complain about reach problems here. It was mentioned before that the 7900 might not be ideal on wider triple setups. For this you would better choose the older 9s FD-7700.


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## scant (Jan 5, 2004)

sergio_pt said:


> I'll see how it works tomorrow when I complete all the tweaks.


cool, I look forward to hearing :thumbsup:


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## sergio_pt (Jan 29, 2007)

manual filing work. in pictures. more comments in a minute. 
sorry for all the dirt and mud but my bike gets used and abused a lot.


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## sergio_pt (Jan 29, 2007)

The DA 7900 FD + speen setup Is ALMOST OK for me if it weren't the problems I found.
It's harder to shift from middle to outer ring probably because of the tight angle the cable makes with the horizontal. The frame is designed to use top pull Der. so the cable stopper/cable are tilted to the left making this strange angle. I'm trying to find a simple solution for this, maybe longer housing.
The chain rubs more easily as I said.
I would not recommend the DA 7900 + speen setup if you have this kind of cable routing. The chain rubbing in the bottom and sides of the cage are almost impossible to avoid. 
If you are willing to ignore this problems the shifting is good I admit. 

Saving 80g from the XT FD was the most interesting part


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## mad dog26 (May 1, 2007)

*DA or XX for 2x9*

I am just building up a new 2x9 that came standard with XTR F mech
I plan to run it as a 2x9 (Race Face Next sl crank) with 22 or 24- 34 or 36 .
Yes i need lower gearing for solo 24 hr racing with lots of climbs.

I want to run a dedicated 2 x F mech (34.9 frame) for low weight, good shifting.

So, will XX F mech work with X0 twist? Do i need to run 10sp chain?
Will DA be better option? I don't have a lot of set up time and do have top pull.
thanks


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## biglines (Apr 6, 2009)

i am going to attempt this FD on my Trek. i have xtr shifters that will be using with the speen adapter and DA 7900. i am however running a 2x9 (26/38) now so i am thinking there wont be any major complications and i won't have to grind on my new DA. just waiting for parts, the waiting is the hardest part!


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## reformed roadie (Mar 30, 2008)

mad dog26 said:


> I am just building up a new 2x9 that came standard with XTR F mech
> I plan to run it as a 2x9 (Race Face Next sl crank) with 22 or 24- 34 or 36 .
> Yes i need lower gearing for solo 24 hr racing with lots of climbs.
> 
> ...


FWIW, Sram has been touting the 1 - 1.5 ratio of chain ring teeth as part of why XX shifts so well up front(26/39, 28/42)...a 24-36 will be the combo.
I think a XX FD, shifted w/ a grip shift will be insanely quick...think about it - twist in the direction you want to go till it stops.

Post if you go that way, as I plan on doing it eventually myself.


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## Jake Pay (Dec 27, 2006)

reformed roadie said:


> I think a XX FD, shifted w/ a grip shift will be insanely quick...
> think about it - twist in the direction you want to go till it stops.


I've been running the XX front derailure since last summer with no issues what so ever...
Shifting is "*insanely quick*" when paired with the XO grip shifter..









I also use KMC's X-10SL and have no chain rub.​


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## nbwallace (Oct 8, 2007)

*Huge amount of effort to shift Dura Ace 7800*

Hi,

I installed a DA 7800 on my sons bike paired with x-7 grip shifts. It setup quite easily in that his Marin Bayview trail is bottom pull. The shifting effort makes it pretty useless for him. Is there something I'm missing?

TIA


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## BruceBrown (Jan 16, 2004)

nbwallace said:


> Hi,
> 
> I installed a DA 7800 on my sons bike paired with x-7 grip shifts. It setup quite easily in that his Marin Bayview trail is bottom pull. The shifting effort makes it pretty useless for him. Is there something I'm missing?
> 
> TIA


Outside of lifting weights with the left hand to strengthen his grip....

I use the 7800 with an X.0 twist grip on one bike, and it's a heck of a twist to get it up to the big ring in my 2 x 9 Middleburn Duo configuration. I haven't tried filing down the endstop to see if that would lessen the twist effort requirement, but I imagine it would. You might try that.

I use the 7900 with X.0 triggers on another bike and it is a much easier shift up to the big ring. I did the modifciation Nino suggested of filing down the endstop and the reach and ease of shifting up to the big ring is very smooth and easy.

BB


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## 2times (Jul 14, 2006)

biglines said:


> i am going to attempt this FD on my Trek. i have xtr shifters that will be using with the speen adapter and DA 7900. i am however running a 2x9 (26/38) now so i am thinking there wont be any major complications and i won't have to grind on my new DA. just waiting for parts, the waiting is the hardest part!


On my 08 Fuel EX 9.0 I am using a 7800 w/speen and sram plasma, no problems what so ever, love it.

You have a thread with your bike on it? I would like to check it out.


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## DeeEight (Jan 13, 2004)

Its because road front derailleurs and mtb front derailleurs have different cage geometry and cable pull requirements for the shifters. Road shifters basically pull less cable per gear change than mountain shifters and the road derailleurs take this into account. Mountain shifters move more cable and with road derailleurs run as they're intended (bottom pull) it not only takes more physical effort to achieve a shift, but unless you're using a friction front shifter (or one with trim stops between the clicks) like a thumbshifter or grip shifter, you won't actually get proper shifts (mtn shifters move the derailleur too far / road shifters don't move mtn derailleurs far enough). You can also run into the above problem of the derailleur body interfering with how far the cage moves.

The speen adapter changes the leverage ratio of the front road derailleur to something that matches the mtn derailleurs close enough that mtn shifters will now actually work with them correctly. I'm not sure why this never got mentioned by Nino.. perhaps he simply never tried running anything except lightweight grip shifters with the road front derailleurs and truly didn't know about it, but its pretty commonly known to actual professional bicycle mechanics.


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## nrsnow (Feb 23, 2009)

I'm using XO trigger shifters. Will a Dura Ace FD-7900 front derailleur work with this setup?


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## 1415chris (Mar 21, 2009)

Let me refresh this thread.
I've been riding the combo xx shifters and da 7900 for a while. Using speen adapter you can make the 7900 working "properly" (movement of the cage), but it doesn't work smoothly as the xx rear mechanism and shifter.
The only way to make this setup working is to move the dlr cable inside the cable bolt, which of course increases the drag significantly.
So I was wondering whether there are any available adapters (speen, carbon ti etc) allowing this combo working smoothly? I know, I can go for xx, but 7900 it’s a really nice mechanism


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## Tiffster (Jan 30, 2008)

I had a similar problem years ago using a Sram red front mech on an XTR crankset. The speen adapter didn't have enough pull to make the shift smoothly.

When you say it doesn't work as smoothly, what aspect ? The shifting quality, force required to shift, chain rub ????

The problem i had was too much force to shift it onto the big ring, all i did was make a homemade speen adapter that was a few mm longer. This reduced the force needed to shift.

I'm currently working on my latest setup which is an XX crank with a 2013 red yaw front mech.


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## 1415chris (Mar 21, 2009)

Moving the cable on the other side of the cable bolt reduces the lever arm distance, smaller torque. You have to balance it by using higher force.
Shifting precision is quite good but this force.....
As you say slightly longer than speen 7900 adapter would solve the problem.


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## Tiffster (Jan 30, 2008)

Just make one then. It's only a piece of steel with two holes in it.

I made mine from brass as it's easy to shape.


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