Dura-Ace front derailleur?

I am not too sure how good of an idea that would be. Technically there is a Dura-Ace front derailleur designed for a triple crankset. But, the new Dura-Ace derailleur is designed to be used with a 10 speed system (narrower chain I believe) and a crankset with a 52 tooth large chainring. If you were to install the derailleur, the cage would not follow the contour of the crank correctly. This will result in the chain not being positioned over the contours in the cage when trying to shift resulting in poor shifting or possible jamming. Also, you may have the chain rubbing on the derailleur cage in certain gear combinations due to where the derailleur is realtive to the chainrings.

This next part I am not 100% sure on but I believe the indexing of MTB front derailleurs is different than that of road front derailleurs too. When Shimano designed components for the flat bar road bikes they needed to make new rapid fire shifters just for that purpose.

Thanks!!!

GearHead said:

I am not too sure how good of an idea that would be. Technically there is a Dura-Ace front derailleur designed for a triple crankset. But, the new Dura-Ace derailleur is designed to be used with a 10 speed system (narrower chain I believe) and a crankset with a 52 tooth large chainring. If you were to install the derailleur, the cage would not follow the contour of the crank correctly. This will result in the chain not being positioned over the contours in the cage when trying to shift resulting in poor shifting or possible jamming. Also, you may have the chain rubbing on the derailleur cage in certain gear combinations due to where the derailleur is realtive to the chainrings.

This next part I am not 100% sure on but I believe the indexing of MTB front derailleurs is different than that of road front derailleurs too. When Shimano designed components for the flat bar road bikes they needed to make new rapid fire shifters just for that purpose.

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Thanks for the input GearHead!! I'll have to look at that when I get a chance. I was looking at doing a FD-7700, but I'll check out the things you pointed out. Thanks again for the help!

psinsyd said:

Thanks for the input GearHead!! I'll have to look at that when I get a chance. I was looking at doing a FD-7700, but I'll check out the things you pointed out. Thanks again for the help!

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Ah, that would be the 9 speed 2 chainring one then. That would only have a capacity of I believe 15T so it won't cover the 22-44 tooth range. Also, it is designed to be used with a chainline of 43.5 mm. Most MTB have between 47.5mm to 50mm chainlines, the derailleur may not be able to travel out far enough to reach the big ring on a MTB crank either.

Why put a road bike fd on at all?

Bikinfoolferlife said:

Why put a road bike fd on at all?

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I believe he wants to save the extra weight.

Thanks GearHead!!

Hey man, thanks a ton for all of your time and input. As you could probably already tell, I'm a relative newb when it comes to setting up a lightweight drivetrain.

The goal was to use the Dura-Ace front derailleur with the BTP adapter clamp to save as much weight as possible without breaking the bank too much!

Again, thanks for all of your help!