Shimano Dura Ace 9000 Mechanical Overview

By Jim Weaver, Service Manager, Fit Werx, VT.

           

As I mentioned in a recent posting about the available upgrades to Ultegra Di2, I recently attended a product introduction and tech seminar put on by Shimano.  The main focus of this introduction and seminar was the new, completely redesigned Shimano Dura Ace 9000 mechanical group.  Everything, right down to the cables, is new, and designed to work as a total system as ideally as possible and the new group is truly an engineering tour de force for Shimano.

The biggest news, of course, is that Shimano is following Campagnolo into the realm of 11 speed, meaning 11 cogs in the rear cluster.  The available range of cogs is no different than previous Dura Ace offerings, meaning that 11 speeds will not now give you a 29 or 30 tooth cog in the rear.  What is does mean is that the gaps between some cogs have been closed by a tooth, making it easier for the rider to find the perfect gear for any situation.  The change to 11 speeds required a complete redesign of the vast majority of individual components in the group and thus almost all Shimano Dura Ace 9000 components are not backwards compatible with any other current or previous Shimano group.

Shifters

            The change to 11 speeds required some changes to the levers internally and Shimano took that opportunity to improve the ergonomics of the lever.  The bottom line of the ergonomic changes is that the overall shifter body is now smaller, more like Di2 levers, making it more comfortable and less bulky feeling than the previous generation.  Shimano also changed the placement of the lever reach adjuster screw and made it much easier to change derailleur cables.  Both are far easier to access than the previous generation of Dura Ace.  Only technicians might appreciate these changes…   So, what about changes that really affect the way things work when riding?  That is what really counts, right?  Well, Shimano did not let us down.

For starters shifting action has been improved.   The movement necessary to shift the gears has been reduced, which means less wrist and hand motion is required.  The physical force/effort needed to move the shift lever has also been reduced due to internal ratchet and lever changes in combination with new cables and housing (see below) and improvements in cable routing.  This reduction varies with a maximum reduction of 47% over the previous generation of Dura Ace.  The feel is also more positive; one of my criticisms of previous generations of Shimano shifters is that they can be very smooth, but that they also can feel vague – Dura Ace 9000 addresses this.  So, the shifting is now easier with shorter throws and quicker and more precise feel.  The front shifter also has a new trim function designed to make chain drop less likely without diminishing shift quality (see front derailleur description below for more on this).   While Dura Ace has always felt like it worked great, let me tell you that these improvements are not subtle; these are significant and very noticeable improvements over Dura Ace 7900.  The shifting action could be argued to rival the feel of Di2 electronic in some regards, which is impressive to say the least.

Crankset

            The Shimano Dura Ace 9000 crankset is very different from the previous generation, and really from pretty everything else on the market.  First of all, it only has four arms to the spider supporting the chainrings instead of the traditional  five.  This, in and of itself, is not terribly rare.  However, what is unique is that the arms of the spider supporting the chainrings are not symmetrically spaced around the crank.  This looks different at first blush, but the change is far more than cosmetic.  Shimano carefully studied the forces on the crank arms and chainrings while pedaling, and has positioned the arms of the crank to better transfer and absorb those forces and support the chainrings accordingly.  The result is less flexing of the crank and the chainrings, which equals better shifting and more direct power transfer.  As an added benefit, getting rid of an arm also makes the crankset lighter.

The second innovation to the crank is that one crankset will now accommodate all available chainring combinations, from 53/39 to 50/34 (standard to compact).  This is the first time a crank from a major manufacturer has been able to accommodate such a change without requiring that you replace the entire crankset.  Shimano cranks have long been known to offer the best shifting on the market and the Shimano Dura Ace 9000 crankset is only going to enhance this reputation as the ramps and pins that help lift a chain onto the large chainring have been redesigned as well.  The downside to all this, if you want to call it that, is that other manufacturers’ chainrings will no longer fit on a Dura Ace crank.  So, for those of you who want to buy a Dura Ace 9000 crank and then replace the incredibly rigid and fantastic shifting hollow outer chainring with a flexy $30 no-name ring that shifts poorly, you can’t do it any longer…  If you have very specific chainring tooth combinations that are not readily available, you may also be out of luck with the new Shimano Dura Ace 9000 crankset as Shimano is currently only producing fairly standard gearing combinations.  Otherwise, the 9000 series crankset offers the versatility of both compact and standard in single cranks and is part of what makes the front shifting on the Shimano Dura Ace 9000 group, as a whole, the best mechanical offering on the market.

The result is Dura Ace now has a stiffer and lighter crankset that shifts even better than its industry leading predecessor, and you can change between compact and standard without changing cranksets.    More good than bad here…

Front Derailleur

             As noted above, Shimano’s front shifting has traditionally been the industry standard.  Shifts were always positive and fast, particularly when shifting to the large chainring.  However, as with all front derailleurs, there are those nagging times when shifting from the large chainring to the small chainring, under pressure, would end up with the chain over-shifting and falling off on some bikes.  Not fun.  The Shimano Di2 electronic shifting front derailleurs addressed this problem by making such downshifts in two steps.  The first step moves the chain to the small chainring, but does not move the derailleur all the way to the inside as that is where the overshift can happen, so the chain rubs a bit.  A moment later, after the chain has fully seated on the chainring, the derailleur makes the final small step to the inside and out of the way of the chain.  It works great.  Shimano has taken that idea and moved it over to the cable-actuated shifter and derailleur on Dura Ace 9000.  When you shift from the large to the small chainring, the derailleur does not fully “get out of the way”, but rather will slightly rub against the chain, until the chain is fully seated on the small chainring.  You then click/trim the front shifter once more, and the derailleur moves out of the chains way completely.  The result is more positive shifting, with less chance of the chain coming off under pressure.  A simple chain watcher, like SRAM introduced on the current RED group, seems like a simpler solution than having to trim the shift lever, but Shimano has never been a company who takes inspiration from others and their system does work well.

Another change on the Shimano Dura Ace 9000 front derailleur is they have lengthened the leverage arm and changed the angle that the cable attaches to the derailleur.  With the advent of internal cable routing, cables no longer approach the derailleur from a standardized angle; cable angles can be all over the place, depending on the design of the bike.  Changes in the angle of the cable’s attachment to the derailleur can affect the quality of shifting.  Without going into an explanation too complicated for this article, Shimano now provides two different attachment options to adapt to varying frame designs.  The result is better shifter response regardless of how the bike frame is designed.

Cables and Housing

            Shimano has introduced a new cable and housing set for Dura Ace 9000 and they sweat the details on one of the most important, yet under-appreciated, components of overall shift efficiency – Shimano even designed 9000 series ferules/housing ends for specific applications (the ferules at the shift lever are different than the ferules going into the frame, for example).  Not using these new cables and housing will result in a loss of at least 10% of the shifting and braking performance of the new Dura Ace 9000 group according to Shimano.

The brake housings are stiffer so there is less compression of the housings when you brake.  This allows more pressure to actually go the brakes themselves, improving brake performance and feel.  The cables now have a polymer (Teflon) coating that helps the cables to slide very smoothly through the housings.  The new cables and housings provide quicker, more accurate shifting, and smoother, more powerful braking, with better feel.

Unfortunately, the new and improved cables and housings will not work well with anything other than Dura Ace 9000.  The cables are simply too slippery for the fixing bolts to hold them securely, particularly on brakes.  The new fixing bolts for Dura Ace 9000 derailleurs and brakes are roughened in a specific way to allow them to adequately grip the cables.  Shimano is working on bolts and plates for previous generations of Shimano components so that owners of older components can benefit from the improvements offered by these new cables and housings.  As of the publication of this posting, these new bolts are not yet available.

Chains

            The redesign of the Dura Ace group has even reached the chain.  Of course, a change was needed to be sure that the new chain would work properly with 11 cogs, rather than 10.  But that is not the only change.  Those of you using Shimano know that the latest generation of Shimano chains are directional, meaning that there is an inside and an outside.  Get the chain on backwards, and shifting REALLY suffers.  Well, the new chain is symmetrical, so there is no longer any need to be concerned about getting the chain on backwards.

Shimano has made improvements to the coatings on the chain that they claim will result in a 20% improvement in chain life – which is a significant improvement.  This new coating is applied to the inner plate, the outer plate, and the roller of the Dura Ace chain.  This same coating will also be used on new Ultegra and 105 chains, to lesser degrees.  The Ultegra chains will get the coatings on the inner plate and the roller, and the 105 chain will get the coatings on the rollers only.  The Ultegra and 105 chains will therefore last longer than before, but not as long as the new Dura Ace chain.

Cassette

            In order to accommodate the additional  cog of the 11 speed cassette, the cassette body is 1.8 mm wider than before.  This added width may well make it impossible to use the new 11 speed cassette on many current wheels.  Most existing wheels will need to have the cassette body replaced with an 11 speed specific version to accommodate the wider cassette.   While many wheel manufacturers will offer an upgrade option for existing wheels, don’t assume that it is a given.  For example, we have been told that Zipp discs manufactured before January 1, 2013 will not be able to be converted (non-disc wheels from the latest generation will though).   On the other hand, just about any Mavic wheel will work with the new 11 speed cassette without any change beyond simply removing the spacer that had to be used with Shimano 10 speed cassettes.

Finally, the new cassette is remarkably light.  It may seem incongruous, but the new 11 speed cassettes are lighter than comparable 7900 10 speed cassettes, even though there is an additional cog. The carrier that supports the cogs is now made of carbon fiber instead of metal alloys, resulting in significant weight savings.  Even without a scale I could easily feel the weight difference.

Bottom Bracket

            Shimano has redesigned the bottom bracket, and the new BB is backwards compatible with previous generations of Shimano components.  The main change is that the external bearings carrier is now smaller (thus requiring a new tool to install).  This redesign has made the bearings smaller, as well as the seals.   Shimano’s bottom brackets have historically been very tightly sealed, which means that it has taken some effort to overcome this drag to spin the crank in the bearings.  Shimano says that the new design has decreased the bearing drag by 50%.  I don’t know about percentages, but I can say that the cranks on the bikes that they had available for demonstration certainly spun much easier than before.

Brake Calipers

            The Shimano Dura Ace 9000 brake calipers have been redesigned with a new pivot system that shortens the distance from the pivot to the brake pad and thus stiffens up the entire structure.  When combined with other little structural changes and the new cable and housing, Shimano claims a 20% improvement in overall braking (power and modulation combined).    The changes in braking performance compared to 7900 are not as tangible when riding as the other very notable changes elsewhere in the group, which likely speaks more to how refined this component already was; previous Dura Ace brake calipers have always been the gold standard in terms of power and modulation, and (with the exception of going hydraulic, which it is hard to imagine Shimano is not working on…) it seems like Shimano’s caliper brakes don’t have a whole lot of room for improvement.  However,  unlike all the other components in the Dura Ace 9000 group, the new Dura Ace 9000 brake calipers are reverse compatible and will work with previous generation and other series of Shimano components.

Summary

            As I was thinking about how to summarize the improvements the new Shimano Dura Ace 9000 offers I realized how influential Shimano’s electronic Di2 componentry seems to be in the improvements made to this new mechanical group.  It is almost like Shimano engineers took it as a challenge to get this next generation mechanical product to mimic the features and feel of their electronic Di2 group as closely as possible.   From shift action, quality and precision (especially in the front derailleur, but rear too) to brake lever hood shape and accessibility, there are a lot of features found in this new group that I doubt would have been as refined as they now are without electronic Di2.   The new Dura Ace 9000 mechanical group has made real and very tangible improvements over the already very accomplished Dura Ace 7900 groupset.  The entire group is lighter, weighing less than 2,000 grams,  shifting is better;  lever feel and adjustability is improved;  grips and ergonomics are more comfortable; braking is better;  and so on…  Each component of the groupset has been improved, along with its performance and the results are impressive.

The competition between Shimano, SRAM, and Campagnolo is really driving each manufacturer to do their utmost to improve their products.   The result is that each generation of components from these manufacturers is usually a major improvement over the last.  It is quite the “arms race”.   When Campagnolo updated their components to 11 speeds a few years ago they seemed to take the lead and the Super Record 11 groupset was the epitome of what was available in just about every regard (with the notable exception of front derailleur performance…).  Then, Shimano introduced electronic shifting with Di2.  Campagnolo answered with EPS.  This past summer SRAM launched its attack with the new ultralight and refined SRAM RED 2012.  Now Shimano has released its response with a truly improved Dura Ace 9000 mechanical group and will soon be releasing Dura Ace 9070 11 speed electronic with a host of upgrades to take on some of what Campy’s EPS system improved upon.  All great stuff!   The improvements that have been made in components are jarringly evident – just ride a bike from five years ago and then a bike equipped with the latest components and you’ll understand how far things have come.  Let’s hope these three manufacturers, and any others brave enough to enter the fray, keep pushing each other to even greater heights.  You and I as riders will happily reap the benefits.

Dura Ace 9000 is currently available on some OEM bikes and is just starting to ship as complete groups for frame builds and upgrades.  Contact us if you want more information of if you want to get your name on a group.