Shimano has released further information on the carbon crankset we first saw at Eurobike and followed up in this story.
The Press Release reads:
Shimano carbon crankset compatible with new Dura-Ace
At the Eurobike show in August 2007 we introduced a carbon fiber Dura-Ace crankset FC-7800C. Originally this crankset was designed to be compatible with the Dura-Ace 7800 series. However, with the introduction of the new Dura-Ace 7900 series this year we decided to change this. We will deliver this crankset to be compatible with the new 7900 group instead.
Additionally, we will be able to provide a special chain ring set to make this crankset also compatible with Dura-Ace 7800.
As announced recently, the new Dura-Ace 7900 has a further refined front shifting performance and trimming of the big chain ring is no longer needed. These features were made possible by a new chain ring design and new front derailleur of Dura-Ace 7900.
FC-7800C has an aluminum core to realize a lightweight yet very rigid construction. By using this technology, Shimano developed a crankset that combines the best of both materials. The aluminum frame ensures a stiff set-up for optimal power transfer while using carbon saves weight. Weight of this crankset (including bottom bracket) is 715 grams.
This state-of-the-art crankset will be available in gear combinations 53/39T and 52/39T in crank arm lengths 170, 172.5 and 175mm.
Available as after market product from end of December 2008