Bicycle Mechanics - Dura Ace cranks with ultegra?

With all the hubbub about the new dura ace crank, and it’s stiffness/weight, etc. I was wondering if it’s strictly a 10-speed piece, or could if it could be used as part of a 9-speed setup. Is there a different style of ramping for the chainrings, or perhaps something to do with the narrower chain that would prevent it’s use.

At worst you put 9spd rings on it? sure you might lose that flashness of the 10spd big ring, but you would retain the qualities of the actual crank?

Brendon

Wouldn't you have to replace the whole bttom bracket in order to change the cranks?

Wouldn't you have to replace the whole bttom bracket in order to change the cranks?
I believe that the bottom bracket is partially integrated with the crank, so yes. I'm not really considering it right now (new wheels first) buit I am curious since I like the way they look and function.

With all the hubbub about the new dura ace crank, and it’s stiffness/weight, etc. I was wondering if it’s strictly a 10-speed piece, or could if it could be used as part of a 9-speed setup. Is there a different style of ramping for the chainrings, or perhaps something to do with the narrower chain that would prevent it’s use.

I checked the Shimano site and here is what they say.

6. Will the new cranks (FC-7800) work with my current 9-speed set up?
The new cranks are designed to be used with the new front derailleur (FD-7800) and chain (CN-7800). The pickup pins and ramps of the new crank will work best with these new parts

The SHIMANO site says a lot of things that while true, are not necessarily accurate. This is to get you to use only Shimano products and to discourage you from doing things that work, but don't make them as much money.

The SHIMANO site says a lot of things that while true, are not necessarily accurate. This is to get you to use only Shimano products and to discourage you from doing things that work, but don't make them as much money.

While I would agree with you to a degree, at the cost of the DA 10 speed components, I would hate to put out that kind of money and find out they were telling the truth.

Hmm.. CyclingNews' article on Chris Horner's bike shows him using the new Dura Ace crank with a 9-speed Dura Ace setup. Link here (http://www.cyclingnews.com/teamtech04.php?id=tech/2004/probikes/webcor_lemond) And he certainly hasn't been having problems winning, so perhaps it is just Shimano looking after themselves in case something goes wrong.

The cassette is compatible, its the bottom bracket that won't work.

The cassette is compatible, its the bottom bracket that won't work.

I know that, the bottom bracket is integrated into the cranks. I was just worried that the front derailleur would have problems shifting since, as georgesnatcher pointed out, shimano says:


Will the new cranks (FC-7800) work with my current 9-speed set up?
The new cranks are designed to be used with the new front derailleur (FD-7800) and chain (CN-7800). The pickup pins and ramps of the new crank will work best with these new parts.

Are the current 9-speed front derailleurs compatible with the new Dura-Ace crankset (FC-7800)?
No. Only the new Dura-Ace front derailleur is designed to work with the new Dura-Ace crankset.

I've been running the FC-7800 with Shimano's 9-speed Dura-Ace derailleurs and cassette...Everything works fine. I was a bit leary at first, but noticed a guy on my team rode the crank with the 9-speed setup and some others on the weekend group rides, too.

I have noticed a slight increase in noise (nothing alarming), but that is most likely due to the 9-speed chain with the crank.