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  1. #1
    Senior Member eja_ bottecchia's Avatar
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    Shimano Dura Ace 7700 to Dura Ace 7900 upgrade

    Quick question...

    I have a 2001 Litespeed Classic equipped with a full Dura Ace 7700 group. Someone has offered to sell to me, for a very good price, a full set of Dura Ace 7900 components, brake lever shifters, front and rear brakeset, front and read derailleurs and a 10 sp. casette.

    My questions is this, IF I upgrade with the components listed above, do I also have to update the crankset and chain rings (I currently run 53-39 with 170 crank arms).

    My friend does not have the DA 7900 crankset/chainring and I kinda prefer the look of the 7700 crankset over the 7900.

    So, can I upgrade all the other components and keep the old crankset?

    Thanks for any help/suggestions.

    BTW, today I saw the last stage of the ToC. I was at the top of the Norwegian Grade (in Thousand Oaks). It was pretty exciting seeing these guy ride up the same hills that I ride on weekends, albeait at a far faster pace.
    My current stable:

    1989 SLX Bottecchia (Campy Athena 11s)
    1999 Cannondale F400 mountain bike
    2012 Bianchi Infinito (Campy Record 11s)
    2012 Colnago C59 in PR99 color scheme (Campy Record 11s)

  2. #2
    Senior Member volosong's Avatar
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    Can't help you on the chain question. I'm struggling with my own chain issues.

    On the ToC, how fast were they going up the Norwegian Grade? Was it a sprint for them, (since it is a relatively short climb) ... or were they struggling like we do, (because of the steepness)?

  3. #3
    Senior Member oldbobcat's Avatar
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    According to Shimano's compatibility pdf, the 7900 front derailleur requires a 7900 or 6700 crank for optimum performance, but it will also work with older 10-speed cranksets. But 9-speed cranksets/chainrings are out of the question. It also requires an asymmetrical 7901, 6701, or 5701 chain. I don't know if 7900 chainrings will bolt to your 7700 cranks, and even if they do all bets are off on shifting performance.

  4. #4
    Senior Member the_don's Avatar
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    If it doesn't have the cranks, then it's not a full set.

    Here is some lists of compatibility from Shimano

    http://www.starbike.com/images/Shima...ngeability.pdf

    http://bike.shimano.com/publish/cont...ty%20Chart.pdf

  5. #5
    Senior Member volosong's Avatar
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    Quote Originally Posted by the_don View Post
    the_don, where does the Shimano R-553, (50/39/30), crankset fit into the scheme? I'm swapping out the "no-name" stuff for Ultegra.

  6. #6
    bike whisperer Kimmo's Avatar
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    Two factors relevant to a crankset's 10spd compatibility:

    1. Tooth offset on the rings. NFI whether you can find ones to make it work...

    2. Spider thickness. Is that the sound of a milling machine I hear...?

  7. #7
    Senior Member liquefied's Avatar
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    Your old crankset will work fine! I ran a DA 7700 crankset on my bike with an Ultegra 6700 chain and FD, I had no problems and it shifted like a dream.

  8. #8
    bike whisperer Kimmo's Avatar
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    I suspected this may be the case. As long as the shifter has enough throw and the chain won't fit between the rings, it should work.

  9. #9
    cab horn
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    Man, i'm really getting tired of correcting the magnitude of wrong information on this forum.

    We've done this conversion, and have tested various combinations of combining 'old' 10 speed and 'new' 10 speed stuff. The bottom line is that the instant you start mixing things, with the exception of rear derailleurs, you lose performance.

    Old 10s crankset on new 10s everything else? Lower performance front shifting than with new 10s cranksets. You also lose the massively stiff large ring that is featured on 7900/6700 systems.

    This is what shimano refers to as 'B' compatibility. Most people have no idea how a properly setup, matched drivetrain is able to perform out of the gate. Most people wouldn't know how to setup one for max performance if they were smacked in the face with it.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

  10. #10
    cab horn
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    Quote Originally Posted by Kimmo View Post
    Two factors relevant to a crankset's 10spd compatibility:

    1. Tooth offset on the rings. NFI whether you can find ones to make it work...

    2. Spider thickness. Is that the sound of a milling machine I hear...?
    Yeah, let's also ignore.

    Chain design.
    Large ring design, pins ramps.

    The new 7900 chain is designed to pickup faster and disengage faster on the 7900 specific chain rings for example. That's why the chains are assymetrical. It makes a big performance difference. A properly setup new 10s front shifting is miles ahead of old 10s in terms of performance.

    If you have no idea what you're talking about, stop talking. It's called a lie.
    Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.

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