All posts in Shimano Dura-Ace

Dura-Ace 7900
How does Shimano push the envelope when the cycling community is just getting up to speed with its last Dura-Ace components? Shimano’s 7900 begins with a new hollow chainring design with a carbon shifting assist profile. The derailleur cables are tucked into the STI Dual Control lever bodies and their shifting action is double speed. The leverage ratio of the brakes is reconfigured, along with the brakepads, to boost modulation and match wet and dry weather stopping. Carbon fiber replaces aluminum in the rear derailleur’s pulley cage, and the world’s fastest-shifting front derailleur is reconfigured to eliminate micro adjustments at extreme chain angles. The 2009 topper? An asymmetric chain that is profiled on the inside link plates to better engage the next larger cogs.

Styled like nothing that came before it, Shimano’s Dura-Ace 7900 group may well be the “Swiss Watch” of the Dura-Ace legacy. It’s mechanical precision is certainly comparable- especially if one has the courage to disassemble the inner workings of its STI dual-action levers-but Shimano’s Di2 replaces the complicated mechanical innards of 7900 with simple (and reliable) electronics. Will Di2 overshadow Dura-Ace STI levers like the electronic quartz movement overwhelmed the self-winding mechanical watch?

(www.roadbikeaction.com)


Dura-Ace was always Shimano’s attempt to make a top of the line parts group, but it was not really successful until 1984.
In 1984, Shimano introduced Dura-Ace S.I.S. (Shimano Indexing System) the first successful indexed-shifting system. It was a 6-speed system with indexed shifters mounted on the down tube.
As with any new product, once it was in regular use, minor problems came to light, and they were rectified in later versions. One of the risks of buying into a brand new system is that you are, to some extent, a guinea pig. All of the compatibility problems associated with older Dura-Ace parts result from genuine improvements that Shimano made after the original introduction.
Since the original Dura-Ace was represented as the top-of-the-line possible with 1984 technology, Shimano had a bit of a problem explaining changes in compatibility. They didn’t want to obsolete earlier Dura-Ace versions and leave their customers stuck with orphaned equipment, but they also wanted to keep improving their products.
The marketing department tried to pass off the differences as signs of Dura-Ace’s higher quality vis-a-vis the lower priced systems.
Dura-Ace went through multiple generations, from 6-speed, through 7-speed and 8-speed through the 1996 model year.
1997 was a very big year for Dura-Ace. The system went to 9 speeds, and that was the most publicised change. In addition, however, the entire Dura-Ace system was re-designed and made to be inter-compatible with other Shimano components.
Shimano Dura-Ace 7800 / 7900
Three key words have emerged as the theme for the DURA-ACE system:
Speed, Smooth and Strength.
Speed and Smooth result in effortless shifting, improved braking operation, enhanced ergonomics and an attractive feeling and design. Strength is focused on the critical need for lightweight without sacrificing rigidity, durability or precision. “100% Power Transmission” is the goal pursued by the fusion of these three concepts.