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Discussion Starter · #1 ·
I have a Dura Ace triple that came with my last bike, and I'd like to switch to a double for the new frame I"m having built (don't really need the triple). I was looking at the crank today, and it seems that the small ring is just bolted directly to the middle ring, not to the actual spyder...so is it basically a double crank with the different middle ring? Or is there some sort of different offset in the crank?

So my next question...if I take off the small ring, run the crank as a double (I could replace the 39 with a "proper" ring), trim the front derailleur to not shift to the small ring....should I get a shorter BB (the one I have now is 118.5) and, could I feasibly use the left triple STI shifter, as long as I didn't use the last detent?

I know it sounds like a bit of fiddling...but it's easier and cheaper than pitching it all to buy new double specific parts.

Thanks!
 

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Remove inner ring, replace bottom bracket and front derailleur, and you're good to go. Replacement of rear derailleur is not neccesary, but if you can get a good deal, it will look better. If you have a 9 speed 7700 system, a 7800 rear and front derailleur will work fine.
Once you set the limits on your front derailleur, it won't matter if you click into the "little ring" position on you left shifter. Nothing will happen.
 

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Discussion Starter · #3 ·
Thanks Mr. Grumpy!

Thanks for the info....I guess the DA triple front derailleur will have too much throw to be able to trim it properly? The fronts are relatively cheap anyway.

As far as a BB....is another Dura Ace worth the cost, or should I look at an Ultegra or 105?
 

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If you have a 7700 series Dura Ace, 105 and DA are probably the only 109.5 BB you'll be able to find...

The 6500 Ultegra's have all but disappeared.

I've done the exact conversion your are talking about... At first I got away with just removing the small ring..I kept everything else the same...It worked fine....in the end, I changed it over to a 109.5bb( Dura Ace), double front derailleur and a double inside ring.
 

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Discussion Starter · #5 ·
7700 series...

Yes, it is 9 speed 7700 series.

Now that I know that the conversion works, I'll do the BB and front derailleur from the get-go...probably look for a new inside ring as well. After all...it is a shiny new Marinoni frame it's going on, but my budget doesn''t have room for brand new DA right now.
 

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I don't recomend a 7700 bottom bracket to anyone except myself. Go with the 105 model.
 
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