# Replace 6770 Rear Derailleur with 9070 or 7970?



## metalheart

Can a 6770 Di2 rear derailleur be replaced with the Dura Ace 7970/9070 and function properly?

Is there any advantage to doing so?

I banged up my rear derailleur and want to replace it and just wondering if there are options other than the 6770.

Thanks


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## Full_Spectrum

9070 should work. Same wires, comms protocol, etc.

7970 will not. Different everything.


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## metalheart

Thanks!


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## agravic

Even though 6770 is 10sp and 9070 is 11 sp?


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## mpcbike

10-11 won't matter, chain width is the same and the derailleur are "dumb", junction box is "smart" and that you program with appropriate settings.


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## agravic

So if I'm understanding you correctly. A ultegra 6770 di2 system can be converted to a 11sp system by merely changing to 9070 RD and reprogramming junction box? Asumming of course with a 11 sp cassette and compatible hub.

If so 6770 shifters and FD will work still. 

I thought the 11 sp chain is narrower than 10. That's why kmc sells specific 11 and 10 sp missing links.


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## mpcbike

I have asked this question of Shimano techs & although they will not confirm or deny anything officially, I am led to believe you can upgrade 6770 to 11 speed with only a cassette/chain & compatible wheel. Have not tried it & cannot confirm, but techs would not say "NO" when asked directly. KMC 11 speed links are based on Campy 11 chain width(narrower). As I understand it(cannot remember 100%), Shimano 11 chain is same outer width but narrower inner width(thinner cogs). Someone feel free to correct me if I'm wrong.


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## agravic

This would be such a budget upgrade if true. Hoping for others with insight. Thanks for then info thus far.


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## rcb78

I have an unofficial answer from our contact at Shimano and it's an interesting one. If you have upgraded the firmware of your 6770 setup to the newest version, then putting a 9070 rear derailleur will effectively make your system function as 11sp. Put on an 11sp cassette and chain and you're golden. The front derailleur will function, but at a 'B' compatibility level due to the wider cage dimension.
So yes it will work, BUT it will no longer function as an 10sp system and will not shift on a 10sp cassette.


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## agravic

That's more reassuring info. I'm sure no one at shimano wants this as widely known since it may cannibalize the newer 9070.

I would be willing to try it but my existing hub is 10 sp.

Are the 7900 cranks 11 sp chain compatible? I'm particularly curious about chainring teeth thickness. 

If the 9070 RD is a can bus network the 9070FD may work as well.


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## Full_Spectrum

I am guessing that the 9070 RD could easily be flashed with the 6770 firmware....to make it 10sp compatible.


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## rcb78

I can't imagine they think it's a very big secret. He was very upfront about the compatibility and the see it as a selling point. The 'push' to do a full upgrade is weight based, 6770 is still a heavy SOB.

The crank will work fine. The inner dimension of the chain is unchanged, meaning tooth thickness on the crank is the same. In fact the cassette cogs are supposed to be the same thickness as well with the spacing being the only change. I haven't measured mine so I can't say for sure, but again, from my reps mouth.
I'm currently running 9000 (mechanical) with a Rotor 3D+ crank & Praxis rings. It works as well with 11sp as it did with 10sp.

As for flashing the derailleur itself, the software knows what specific derailleur it's connected to, I don't think the it will allow for flashing a ROM to a device it wasn't 'designed' for. My understanding is that it would have to be a hack/mod.




agravic said:


> That's more reassuring info. I'm sure no one at shimano wants this as widely known since it may cannibalize the newer 9070.
> 
> I would be willing to try it but my existing hub is 10 sp.
> 
> Are the 7900 cranks 11 sp chain compatible? I'm particularly curious about chainring teeth thickness.
> 
> If the 9070 RD is a can bus network the 9070FD may work as well.


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## r1lee

10spd and 11spd will be determined by the shifters, not the deraillieurs. So if you have 6770 and you add the 9070 rear brifters, you system should automatically become 11spd.

And the same can be said if you want to use your 10spd wheels on 9070. You must have 6770 brifters for it to work.


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## Cinelli 82220

The pro peloton is full of guys running 7900 SRM cranksets with 11 speed derailleurs.
So I assume the crank is compatible?


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## carbonLORD

r1lee said:


> 10spd and 11spd will be determined by the shifters, not the deraillieurs. So if you have 6770 and you add the 9070 rear brifters, you system should automatically become 11spd.
> 
> And the same can be said if you want to use your 10spd wheels on 9070. You must have 6770 brifters for it to work.


Incorrect. My Shimano rep says change the RD and Cassette and you're good to go.


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## agravic

Still need a 11sp hub and 11sp chain to go with the rd-9070 and cassette. In the grand scheme of things, probably cheapest 11sp ui2 setup.

Who is going to be first to definitively prove it?


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## mpcbike

Why the rd? It was suggested to me by Shimano techs that 6070 will do 11. They said travel was the issue, but 10speed der has plenty of extra movement to cover extra cog. Shifters and derailleurs are "dumb" and have no mechanical limit at 10. I'm led to believe that cassette(wheel), chain & reprogram are all that's needed! Maybe a 9070 main junction box as its the one "smart" piece...? But current e-tube hardware makes no distinction, so I think not.


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## carbonLORD

mpcbike said:


> Why the rd? It was suggested to me by Shimano techs that 6070 will do 11. They said travel was the issue, but 10speed der has plenty of extra movement to cover extra cog. Shifters and derailleurs are "dumb" and have no mechanical limit at 10. I'm led to believe that cassette(wheel), chain & reprogram are all that's needed! Maybe a 9070 main junction box as its the one "smart" piece...? But current e-tube hardware makes no distinction, so I think not.


It was irresponsible for your tech to say that, when it is not possible. The throw of the 6070 is not enough and there is no program to support it regardless (and I'm not one for hacking it to have little support and sketchy functionality, all for one more cog).

However, adding a proper 11 rear, cassette, chain... and for some a cassette body swap (King hubs rule). You can be on the new DuraAce 11 where it matters most and I think that in itself is pretty cool, for those who want it.

I've been perfectly satisfied with the multishift update that I don't feel compelled to go through the hassle of an 11 update just yet (and my other bike has SR11 mechanical so I know what I'd be missing, in terms of a extra gear anyway).

When they make the DuraAce stuff in something other then flashy silver I'll tinker but by then I'm betting some new Ui2 Ultegra 11 shadow product will be around, (I just got my Di2 so it's still fresh to me).

Now, I just need to get a Windows back end on my iPad mini so I can run the etube software through it, (or an iPhone).

Puzzles me why Shimano of all companies doesn't have an iOs app for etube. Now there's a hack I'm interested in!


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## mpcbike

Programming is an issue, but I don't see a problem with throw on 6070. Plenty of room at limit screws.


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## young-nyc

Agree with carbonlord, would be amazing if they had an iOS app for etube. 
The only issue I could see is that apple's protocols probably won't let 3rd party apps to sendout data via USB.


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## young-nyc

Actually never mind, realized there are apps on the market that interfaces with our car's OBD computer and also allows it to reset the check engine light. So if this is possible so would an ETube app that would interface with our Di2's

So to sum things up for Ultegra Di2 owners who want to upgrade to 11 speed,
There are 2 options based on this thread. 
1) get a 9070Rear Shifter which "technically might" allow the 6770 RD to act as an 11speed or

2) get a 9070 RD which "technically might" allow the Ultegra di2 system to recognize that it is now an 11speed. 

Both theories are from Techs. 
In Both cases rider has to upgrade the cassette and wheel hub. 
Hmmm wonder who will be the first guinea pig? 

Should be interesting.


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## kiwicyclo

This sort of sums it up.


"_* Due to the E-Tube wiring, none of the electronic components of Dura-Ace Di2 7970 are compatible with the new 9070 Di2. Those with Ultegra Di2 are in for a little better luck. Although it would still be a hefty investment to go from Ultegra’s 10-speed to an Ultegra/Dura-Ace Di2 11-speed setup, it’s completely possible. New derailleurs, chain, and cassette would be a must according to Shimano, and potentially a new crank due to differences in spacing. An 11-speed compatible rear wheel is also necessary, but since many of the wheels made over the past year are already designed for the extra gear you may already be good to go. Shimano is quite clear on what they deem the term “compatible” to mean, and that’s perfect integration. The biggest boon to Ultegra Di2 users is the fact that the internal battery will work with their system (a junction box is also necessary for charging), in addition to the aero bar extension shifters and the climbers switch.  "*_


All the cables, shift methods (TT Bar extensions, Bull horn shifters, sprint shifters, climbing switches) are inter changable between ultegra Di2 / 9070 Dura Ace Di2


** All TT shifters are Dura Ace 9070 any way.

On the wheels / hubs . . I have successfully machine 1.85 mm of my powertap hub (SL+) so it can run 11 speed. All I do is put on a 1.85 mm spacer back on the hub to run 10 speed if I want to.

I have also machined 1.85mm of my bontrager 90 mm hub, this also fits a dura ace 11 speed cassette.

I purchased the DTswiss 11 speed free hub body for my reynods 66's, this was a 30 second swap out.

All you have to do is see if you have enough "flange" on the hub to have 1.85 mm machined off the back of the free hub body (rotor) to fit on the new 11 speed cassette.

The 7900 chain rings work fine on the DA9000 chain as the internal dimensions of the chain are the same, it is only narrower on the OD.

Where does the 11 speed functionality lie? Surely there must be a dealer out ther who can simply take a 6770 Ui2 rear derailleur of a bike, plug in a DA9070 rear derailleur and see if it shifts 11 speed or steps 11 speed.

I hope to be able to test this personally inside a couple of weeks.

Hope this all helps.

I currently run a DA9000 mechanical Trek Madone 7 series and looking at upgrading my current 9 series Trek speed concept for DA7970 to DA9070 in a couple of weeks.

Cheers


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## young-nyc

Good luck and hope you'll be one of the first to report back with some good findings. :thumbsup:


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## TomasK

kiwicyclo said:


> This sort of sums it up.
> 
> 
> "_* Due to the E-Tube wiring, none of the electronic components of Dura-Ace Di2 7970 are compatible with the new 9070 Di2. Those with Ultegra Di2 are in for a little better luck. Although it would still be a hefty investment to go from Ultegra’s 10-speed to an Ultegra/Dura-Ace Di2 11-speed setup, it’s completely possible. New derailleurs, chain, and cassette would be a must according to Shimano, and potentially a new crank due to differences in spacing. An 11-speed compatible rear wheel is also necessary, but since many of the wheels made over the past year are already designed for the extra gear you may already be good to go. Shimano is quite clear on what they deem the term “compatible” to mean, and that’s perfect integration. The biggest boon to Ultegra Di2 users is the fact that the internal battery will work with their system (a junction box is also necessary for charging), in addition to the aero bar extension shifters and the climbers switch.  "*_
> 
> 
> All the cables, shift methods (TT Bar extensions, Bull horn shifters, sprint shifters, climbing switches) are inter changable between ultegra Di2 / 9070 Dura Ace Di2
> 
> 
> ** All TT shifters are Dura Ace 9070 any way.
> 
> On the wheels / hubs . . I have successfully machine 1.85 mm of my powertap hub (SL+) so it can run 11 speed. All I do is put on a 1.85 mm spacer back on the hub to run 10 speed if I want to.
> 
> I have also machined 1.85mm of my bontrager 90 mm hub, this also fits a dura ace 11 speed cassette.
> 
> I purchased the DTswiss 11 speed free hub body for my reynods 66's, this was a 30 second swap out.
> 
> All you have to do is see if you have enough "flange" on the hub to have 1.85 mm machined off the back of the free hub body (rotor) to fit on the new 11 speed cassette.
> 
> The 7900 chain rings work fine on the DA9000 chain as the internal dimensions of the chain are the same, it is only narrower on the OD.
> 
> Where does the 11 speed functionality lie? Surely there must be a dealer out ther who can simply take a 6770 Ui2 rear derailleur of a bike, plug in a DA9070 rear derailleur and see if it shifts 11 speed or steps 11 speed.
> 
> I hope to be able to test this personally inside a couple of weeks.
> 
> Hope this all helps.
> 
> I currently run a DA9000 mechanical Trek Madone 7 series and looking at upgrading my current 9 series Trek speed concept for DA7970 to DA9070 in a couple of weeks.
> 
> Cheers


I try to update the 6770 system to work on 11sp without success, you need to use the DA9070 f/r to work with the 11sp system, the derailleur determine the amount of gear that the system can use.


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## Cinelli 82220

young-nyc said:


> Good luck and hope you'll be one of the first to report back with some good findings. :thumbsup:


It's already been done. See the Mix and Maych Ui2 and Di2 thread.


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## young-nyc

yup just read the mix and match thread,
http://forums.roadbikereview.com/sh...ra-di2-dura-ace-9000-di2-possible-303900.html
however i guess we all want to know if it's possible to just upgrade the RD to 9070 instead of upgrading both the RD and FD to make it work?


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## Cut.Aussie

I have already made the Ultegra to DA 9070 upgrade, see my post elsewhere.

If you just plug in the 9000 RD with the Ultegra FD it gives you 10 speeds, then plug in the 9000 FD and the 9000 rear suddenly gives you 11 speeds which kind of makes sense when you think about it, with the 11 speed cassette having a wide chain sweep you would need the 11 speed front to match.

So, poor mans upgrade is FR, RD, cassette, chain and a wheel that will mount the cassette such as Mavic and others, you can use all your other Ultegra stuff like levers and even 10 speed crank in a pinch.


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## pataww2001

very interested in doing this......


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## chojn1

This mis-mash upgrade is no longer allowed by Shimano.


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