Saturday, June 13, 2015

Shimano Dura-Ace 9000 Cassette

Time to disassemble and compare the Shimano Dura-Ace 9000 11 speed cassette! I had previously compared the Ultegra 6800 cassette with the Shimano 105 5800 cassette, both 11 speeds.

How does the Dura-Ace cassette differ from the other cassettes? What extra feature do you get for the higher cost of the cassette? Let's find out.

11-25T cassette, installed on the Dahon Boardwalk during the upgrade to 11 speeds.

Being a compact 11-25T cassette, it weighs very little, at only 176 grams. This is much lighter than the 11-28T Ultegra or 105 cassettes which weigh well over 200 grams.

Exploded view of the cassette sprockets! 11-12-13-14-15-16-17-19-21-23-25 gear combination.

Lots of holes and grooves on the sprockets, to maximise the weight savings.

One difference that I noticed between this Dura-Ace cassette and the Ultegra cassette is that the spiders on the sprockets are designed differently. For the Ultegra cassette, the 1st to 3rd largest sprockets are riveted together, while the 4th and 5th sprockets are also riveted together on another spider.

As for the Dura-Ace cassette, the 1st and 2nd largest sprockets are riveted together, and the 3rd to 5th sprockets on another spider. This arrangement of sprockets on the spiders are different between the cassettes.

The major difference between this Dura-Ace cassette and the other cassettes is the use of titanium for the largest 5 sprockets. This translates into a good amount of weight saving, but at a much higher cost.

Weight of the largest 2 sprockets. Made of titanium for maximum weight savings.

The next 3 sprockets are also made of titanium. Riveted onto a carbon fibre composite spider.

Together, the largest 5 titanium sprockets weigh only 95 grams, which is just slightly more than half the weight of the entire cassette.

11-25T printed on the largest aluminium spider with the 23T and 25T sprockets.

Next 3 gears are the 17T, 19T and 21T sprockets.

Interesting layout of the rivets and shape of the carbon fibre composite spider. This design seems to enable the sprockets to reinforce each other for greater strength.

All 5 titanium sprockets, mounted to the 2 different spiders. Aluminium spider on the left, carbon fibre composite spider on the right.

Difference in surface finishing between the steel sprocket on the left and the titanium sprocket on the right.

The main advantage of the Dura-Ace cassette over the Ultegra and 105 cassettes is the weight. Other than that, the shifting performance would probably be similar. For most people, using the Ultegra cassette is a good option as it shifts well and is also quite affordable. The Dura-Ace cassette is a luxury that is nice to have but not really necessary, even for competitive riding.

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