# Dura Ace compatibility...



## Quattro_Assi_07 (Jan 13, 2006)

Can someone tell me if Dura Ace SL-7700 9 speed index down tube shifters are compatible with Dura Ace 7410 8 speed group?


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## Peanya (Jun 12, 2008)

From my understanding, the rear derailleur would work, but you would need a 9sp cassette to make it work.


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## Quattro_Assi_07 (Jan 13, 2006)

Peanya said:


> From my understanding, the rear derailleur would work, but you would need a 9sp cassette to make it work.


So it is the 9 speed spacing that is different when going from 8 to 9?


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## Peanya (Jun 12, 2008)

yes, the hub stayed the same size, but the spacing of the cogs and the indexing changed. Also, there was one model of DA hub was exclusive, but I believe it was a 10sp. Don't quote me on that though!
Post the link to this in the components & wrenching section (so you're not double posting) and I'm sure you'll get more specific answers.


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## Bridgestone (Sep 6, 2007)

If you use a DA rear 8 speed derailleur, any shimano 8 speed cassette, 9 speed shifters work fine.http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3946, http://www.sheldonbrown.com/dura-ace.html

I am running 9 speed ultegra R shifter with 8 speed DA drivetrain.


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## Dave Hickey (Jan 27, 2002)

Quattro_Assi_07 said:


> Can someone tell me if Dura Ace SL-7700 9 speed index down tube shifters are compatible with Dura Ace 7410 8 speed group?



They will shift 8 speed perfectly... Hook it up normal and don't use the extra click.

The 9 speed DA shifters( or any 9 speed Shimano shifters) shift for 8 speed spacing when hooked up to a Dura Ace 7400 series rear derailleur... It's a unique situation and it was designed that way by Shimano.

My J P Weigle is set up that way

Trust me on this one.....Perfect shifts....and the silver 9 speed shifters look better than the gray 8 speed Dura Ace shifters...


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## Quattro_Assi_07 (Jan 13, 2006)

Dave Hickey said:


> They will shift 8 speed perfectly... Hook it up normal and don't use the extra click.
> 
> The 9 speed DA shifters( or any 9 speed Shimano shifters) shift for 8 speed spacing when hooked up to a Dura Ace 7400 series rear derailleur... It's a unique situation and it was designed that way by Shimano.
> 
> ...


Ok, that sounds good. The reason I ask is that you had said a while back when I was thinking of using 7900 series shifter levers and a 7400 RD...


_1. DA 7900 shifters won't work with 7400 series derailleurs..The 7400 derailleur has a unique pull ratio that will only work with 7400 series shifters._

Is there any difference bewteen 7400, 7401, and 7402 rear derailleurs? I believe the RD that I have and want to use is a 7401 and came to me as part of a 7 speed group I had purchased. I originally wanted to just get an 8 speed shift lever but they don't seem to show up all that often and like you said, the silver finish of the 7700 series is a lot nicer.

Another question for you... since I will go the route of 7700 9 speed shift levers, can I go ahead and use a 9 speed cassette on 8 speed hubs? If this can be done, would there be any benefit in using the 9 speed cassette versus the 8 speed other than having one extra gear? Did the shifting improve at all?

Thanks,

James


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## Dave Hickey (Jan 27, 2002)

Quattro_Assi_07 said:


> Ok, that sounds good. The reason I ask is that you had said a while back when I was thinking of using 7900 series shifter levers and a 7400 RD...
> 
> 
> _1. DA 7900 shifters won't work with 7400 series derailleurs..The 7400 derailleur has a unique pull ratio that will only work with 7400 series shifters._
> ...



1. 8 speed spacing is different than 9 or 10 speed.You can't use 7900, 7800, or 7700 shifters to shift 9 or 10 speed with a 74xx series derailleur.. you can use them to shift 8 speed when connected to a 74xx series rear derailleur. 

2. Shimano made minor changes to deraileurs 7400, 7401, etc... but it doesn't effect shifting or the number of cogs you can use, Any 74xx series derailleur will shift 6,7, or 8 speed when connected to the appropriate shifters..

3. When I replied in a early post about 7900 shifters not working with 74XX derailleur, I believe you were asking about using it to shift 10 speed not 8....

I know this gets confusing....Dura Ace 74xx series derailleurs have a unique pull ratio that is unlike any other Shimano derailleur..Simply put; for every click of a shifter, the 74xx series RD will travel a larger distance than other Shimano derailleurs

Shimano abandoned the idea and, starting with the 7700 series, made the DA rear derailleurs with the same pull ratio as all other Shimano derailleurs

Back to your original post, you are fine when using 7700 shifters with a 74XX RD only if you want to shift 8 speed..You cannot use this combination if you want to use 9 cogs...


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## Peanya (Jun 12, 2008)

I thought it was the spacing. Guess I was wrong on that one. My apologies.


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## zmudshark (Jan 28, 2007)

There are two people that should never be doubted, Scooper and Dave Hickey.

They know their stuff.


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## Quattro_Assi_07 (Jan 13, 2006)

Dave Hickey said:


> 1. 8 speed spacing is different than 9 or 10 speed.You can't use 7900, 7800, or 7700 shifters to shift 9 or 10 speed with a 74xx series derailleur.. you can use them to shift 8 speed when connected to a 74xx series rear derailleur.
> 
> 2. Shimano made minor changes to deraileurs 7400, 7401, etc... but it doesn't effect shifting or the number of cogs you can use, Any 74xx series derailleur will shift 6,7, or 8 speed when connected to the appropriate shifters..
> 
> ...


Sorry Dave, my original question was clear as mud, as they say...

_"this one will be a full DA 7400 8-speed series build except for the shifters. I am out of 7400 series 8-speed shifters (out of all DA 7400 parts now except for 7410 crankset) but do have a set of DA SL-7900 downtube 10-speed shifters. I was wondering if there are any compatability problems to think about before using them with the 8-speed stuff.

One other question, can the 7400 DA hubs work with a 10-speed cassette? I don't think there should be a problem with the 7400 rear derailleur handling the extra 2 cogs, would there? I am thinking the cassette hub has a different spline profile... ?"_

Too many similar questions at one time but what I want to do is use the 7700 series shift levers with a 7400 series RD and 8 speed cassete. I have all the parts to do that and from you now, at least I know it can be done. The other questions were about using 9 and 10 speed cassettes along with the 9 or 10 speed shifters (with 7402 RD) and I see now why they will not work.

A few more questions for you... if I were to use a 7700 series RD with 7900 series shift levers, could I then run it with a 10 speed cassette? I still would like to use my 7410 crankset and 7410 FD and I have 7403 8 speed hubs. Can this be done and if so, would this require a 10 speed chain?

Thanks again,

James


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## zmudshark (Jan 28, 2007)

Dave, Do you have any idea how a set of Dura Ace 8 speed STI's, coupled with a 7402 RD would mate up with a Campy 8 speed wheel, apart from the planets being tossed off their axises and all of that ?


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## steelbikerider (Feb 7, 2005)

DA 7400 hubs can take a 10 speed cassette if they have the internal threads on the cassette body. I can interchange my 7400 wheels with 7850 wheels with no adjustments. Be sure to use the spacer provided with 10 speed cassettes


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## Dave Hickey (Jan 27, 2002)

zmudshark said:


> Dave, Do you have any idea how a set of Dura Ace 8 speed STI's, coupled with a 7402 RD would mate up with a Campy 8 speed wheel, apart from the planets being tossed off their axises and all of that ?



It should work....The reason I say that is Shimano 7 speed cassette cogs are 5.0mm apart and so is 8 speed Campy... I've shifted 7 speed Shimano with 8 speed shifters with no issues


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## zmudshark (Jan 28, 2007)

Dave Hickey said:


> It should work....The reason I say that is Shimano 7 speed cassette cogs are 5.0mm apart and so is 8 speed Campy... I've shifted 7 speed Shimano with 8 speed shifters with no issues


I'll let you know in a couple of weeks, when the parts arrive. I'm thinking it should be 'close enough'.


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## Bridgestone (Sep 6, 2007)

zmudshark said:


> Dave, Do you have any idea how a set of Dura Ace 8 speed STI's, coupled with a 7402 RD would mate up with a Campy 8 speed wheel, apart from the planets being tossed off their axises and all of that ?


I think it should work also. I share three wheelsets running sachs eight speed fw's (4.8mm spacing) between a Campy record eight speed bike and 7402 DA RD and Ultegra 9 speed brifter bike. They work equally well.


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## zacolnago (Feb 15, 2006)

I'm so glad I read this thread. Thanks goes out to all you Dura Ace geniuses.


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## karyg (Feb 17, 2004)

*one more question to add to the confusion*

Dave,
Can I use my DA 8sp shifters with a DA 7700 RD to shift 8sp or do I need a 74XX RD?
thanks


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