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Dura-Ace 2004: In the flesh
By Paul Mirtschin with Mark Shimahara
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For the past few months, the cycling public has been privy to random snippets of information about the 2004 Dura-Ace: occasional photos of Lance Armstrong's bike, press releases from Shimano and the usual rumours.
When Mark Shimahara popped along to visit the Rabobank training camp, he got a chance to not just look at Levi Leipheimer's Dura-Ace equipped bike, but to speak to Rabobank mechanic Bart van Go about how it all falls together.
Lots of questions about the new gear have centred around the new bottom bracket and cranks. How does the new bottom bracket work; how does the new design affect the pedal spacing (aka "Q-factor"); how does it all fit together?
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Well as you can see from the photos, the bottom bracket bearings sit more-or-less where the exposed section of axle is on your current bike. So there appears to be no change in the Q-factor, but there should be a significant reduction in the loads on the bearings, and, theoretically, a longer bearing lifespan.
The new chainring design is also a hot topic of conversation, and even if you don't like the look of it, all reports are that it is one of the stiffest and better shifting chainrings out there. And if you take a look at this photo you can see that there really is no spare metal in the back of the crank.
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The new 2004 Dura-Ace chain is something that hasn't garnered much attention; after all, what can be so exciting about a chain? Well with Shimano completely changing the pin design so that nothing is sticking out of the side-plates, it has managed to make a thinner chain without reducing the plate-to-plate measurement too much.
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The new STI levers now incorporate a lot more plastic composite, allowing less-stressed parts to be made lighter. Both the rear derailleur and brake calipers also feature the same plastic composite material.
The reach on the STI levers is noticeably shorter. We know riders who can't get on with previous STI systems at all because the throw to the levers is just too great, so this should broaden the range of people who can use Shimano's top kit.
Photos
Images by Mark Shimahara/BikeZen.com
- Leipheimer's bike equipped with new Dura-Ace.
- A closer look at the bottom bracket.
- The new integrated lever which appears to use more plastic (black).
- The new STI levers, with a noticeably shorter reach.
- The axle is permanently affixed to the drive side crank arm, but the left crank arm can be removed.
- Sealed bearings (black donut shaped, on outside) and cups are joined by a plastic connector. Mechanic Bart van Go best explained the new crank as installing "just like the [threadless compression] headset"; the drive side crank and axle are like the fork and steerer, the shell is the headset, and the left crank fits as the stem.
- Close-up of Levi's crank.
- A look at the drivetrain from the back.
- Instead of sticking out, pins are flush with each link to reduce the chain width.
- A closer look at the brake calipers (again integrating plastic components), which are lighter than before.
- The deraillleur from the back.
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