BEST of PEZ ’08: First Look At DA-7900
Here it comes…! Shimano has ‘officially’ unveiled their newest Dura-Ace gruppo for 2009. Early hands-on accounts are glowing, and it seems the performance bar has been raised once again. Team Highroad mechanic Benny Devcich has been working with the protos and testing for some time, so we asked him to take us through the line.
The Best of PEZ – To help make brighter these winter days, we’ve selected for your viewing pleasure some of our Best Stories of the Year. Who decided which of our stories from 2008 were the best? – we did! Through the next week we’ll present for your consideration some of the work we’re most proud of, and hope you enjoy one more look as much we do. Sometimes a glance back helps clear the path ahead. This story originally ran in June 2008.
The very redesigned 2009 Dura-Ace gruppo arrives with some big changes – most visible being the internal cable routing from the levers and a new shape to the hoods, but perhaps more noticeable will be the shifting and braking performance. The whole group has shed some weight, and although not yet the lightest in class, it’s still only 2045 grams total, and that’s about 5 dimes away from the ‘magic’ kilo mark. But we’ll let Benny take it from here…
The cables go inside, and the levers and hoods get brand new shapes.
– Reported by Benny Devcich – Team High Road –
One of the nice things about working for a large Pro Team, is the new equipment we get to play with and test. Normally it’s new frames, new wheels or things as simple as a new saddle. But upon our arrival in Sicily, a few days before the Giro started, we got a message to expect a couple of the new 2009 Dura-Ace groups sets. It’s not as if we didn’t have enough work on our hands in the days leading up to the start, but that’s all part of the job.
• Benny in action at the Giro start in Palermo.
What we didn’t know is that the new group sets came with a team of technicians to set the new gear up as well. Included in this group was the man responsible for the shifter design, the chainring designer, and the chain designer. For me this was great, to put a face to a product, and to see the engineers who’s last year or so was dedicated to designing these components. My small knowledge of Japanese language came in handy when asking a million questions on the design changes and features of the new products that we were fiddling with. Much like a proud new mother showing off her new baby, each of the engineers gave me all the answers I needed, and showed me all the fine details before they proceeded to assemble the two bikes with the stuff.
Direct from HQ – the new gruppos arrived with their own tech crew.
There were a few prototypes of the new group that I’d already seen on some of the Shimano sponsored pro teams, some as early as last year’s Tour (bet you never even saw it), but until now was still in the design stages. Now it was our turn to have two of our GC riders testing the final prototypes, or working models, for the next month.
The new Dura-Ace 7900 Series comes with everything you see here.
Two riders had been chosen for the test groups, so we assembled the frames, bars etc, ready for their assembly to begin. We had a few other frames to swap over, and a couple of new bikes to build, so we had no time to watch the Japanese masters at work.
They had a few suitcases packed with the new groups, carefully unpacking each part, recording the serial numbers, and marking every component for future inspection. It was going to take them all day to build one bike, with four engineers, we did not have that luxury. Four bikes: one mechanic was our ratio for the day. We left them to it, but I was checking every step of the project, just to get familiar with the group in case of issues during the race.
Hmmm – something looks conspicuous by its absence…
I think the most noticeable change is the lack of cables coming from the inside of the shifters, which made Shimano unique. That distinct Shimano look has also been a point of contention amongst many riders…
But now Shimano has joined the ranks of the ‘hidden cables’, even though they have sworn for years, shifting quality is jeopardized by doing so. Now they have made a few changes to the internals of the shifter, and to the cables to make up for this.
Shifting actuation functions just like the current Dura-Ace… only better.
LEVERS – A Big Change
• ST-7900 Dura-Ace Dual Control Levers
Shimano Says: The new STI Dual Control levers offer a refined ergonomic shape while reducing the weight by over 40 grams. With a Shimano first, the new STI levers offer unidirectional carbon fiber lever blades which reduce weight and offer shift cables hidden under the handlebar tape for a more sleek design. Using a revised internal mechanism along with PTFE lined casing, the shifting is still as light as ever. Shifting stroke for the rear derailleur has been reduced by 20% for quicker shifts and a built in reach adjuster allows for fine tuning the fit for riders with smaller hands.
Getting my hands on the lever for the first time was kind of strange. It didn’t have the weight of a normal shifter, I suppose when you handle these all the time, a small change is noticeable. But this was a big change, not only from the carbon lever, but the whole unit felt hollow, as if they had left out the shifting mechanism itself. [Pez Tech Ed Charles: The new levers are supposed to be 40 grams lighter, but with Proto’s it could have absolutely been different.] There were two options for the shifter cable, running on the outside of the bar, or inside, running next to the brake cable. We opted for outside, as it looked like it was a nicer line for the cable to run.
As You Wish: Cable routing can now run on the same side, or opposite sides of the handlebar.
The Engineers assured us there was no difference whichever way we chose. It felt a lot fatter when you wrapped your hands around them, a least 20% more girth than the standard. It felt very flat, not like the rounder feel of today’s shifters. Close your eyes, and you can swear they feel like Campag or SRAM, a nice flat platform, from bar to shifter.
It took a while to find out where the shifter cable was inserted (underneath the unit as opposed to the current position), but peeling the hood back a little, revealed the secret. The alloy front cap had to be removed to get access to the brake cable. This cap also revealed a nice little adjustment screw, for adjusting the reach of the shifting lever. Perfect for those of you who have smaller hands, and perfect for most of the women I know who ride, (similar to the action of the adjustment screw you find on the entry level Sora) this saves packing the lever with a shim, to pull the lever closer to the bar. The lever was offset a little (looking front on it looks like the bottom of the lever is spread out a little more than normal), with the lever set a little closer to the bar, you still had full braking, as the brake lever didn’t hit the bar directly.
The cables are coated with Shimano’s top secret Teflon mix. The coating is special, and expensive, so both the brake and shifter cable was only half coated to save costs (and you could see the change). [Tech Ed Charles: It’s Polytetrafluoroethylene “PTFE” same stuff as some of the available auto oil additives and what they use to make non stick coatings for pans. It’s also a damn nice water blocker, film and corrosion shield.]
This ensures smooth shifting with the cables hidden underneath the bar tape, regardless of what route they take. The outers have no change to them, great for retail, as you won’t need to carry extra product.
• BR-7900 Dura-Ace Brakes
Shimano Says: Increased linear response, improved braking power, and reduced weight all make their way into the latest version of the Dura-Ace brakes. A new brake pad compound doubles wet condition performance, while also improving dry power by 20%. Enhanced linear response comes from a redesigned caliper arch while a lower profile cable stop creates better lines for the cables and reduces cable friction. While other brakes ditch sensible features like a spring tension adjuster or adjustable toe, the new Dura-Ace brakes still come equipped with those features and manage to drop nearly 30 grams per pair.
Benny Sez: The brake calipers felt similar in weight, a lot lighter though when comparing with a current caliper in the other hand. [Tech Ed, It’s 30 grams with adjustable spring tension and a slightly new shape]. You could see small change in the shape, a lot skinnier, with some nice lightening holes (almost like old school drillium) if you looked a bit closer. The main fixing bolts were titanium, a nice change. The actuation arms that operate the brake itself were a little bit longer, giving a little bit more braking power, but it was hard to tell at low speed. Some new cable adjusters were the other nice change, giving the opportunity to adjust the brake modulation while riding.
With the full carbon brake levers, they felt a little squishy under braking, not the firm feel the old levers give. But a few km down the road, I loved the feeling of the lever under braking, a little bit of suspension (nice vibration dampening) in the lever, made up for the increase in braking power (think that it’s a hard thing to test, as I never give the brakes a real good squeeze, as going over the bars is not my favorite pastime).
New Chain – Major Work
• CN-7900 Dura-Ace Chain
The new chain with slots, hollow pins… and a hair.
Shimano Says: The new asymmetric design of the Dura-Ace chain has redesigned plates that improve the contact interface with the cogs and reduce the chance for chain suck on the chainrings. Other improvements to the links provide greater durability and life with less noise and smoother function. The chain uses hollow pins and weight drops by over 18 grams even with the addition of a quick connection / removal link. A departure from the traditional Hyperglide connection pin, the SM-CN79 quicklink provides a reusable connection and removal point for the chain. The quicklink can be used on any Shimano 10-speed chain and the new chain can also be joined by a traditional Hyperglide 10-speed connection pin if necessary.
The chain has had a major work over, taking a lot of fat off it, and giving a real sculptured look to it. Not only does it have hollow pins, but also every side plate has lightening slots cut in to them. [Tech Ed: That’s another 18 grams down]. The chain really feels light, (not instilling much confidence initially) but we are told it is a little bit stronger under load. It is a single sided design, with many different chamfers and shapes cut into the outside, the inside looked normal. All the changes were for the one reason only, better pickup from small to big chainrings. With Dura-Ace finally succumbing to compact drive, this will aid in the shifting performance of this traumatic shift that compacts are known for. We were very happy to find out that our standard Shimano chain tools would work fine on the hollow pins, and they did. The other cool thing was that it fits a standard chain pin as well, though it might add a little bit of weight to the bike, in it not being hollow.
Front Derailleur – Tears To My Eyes
• FD-7900 Dura-Ace Front Derailleur
Shimano Says: The new Dura-Ace front derailleur cage eliminates the need to manually trim the front shifting. Additionally, the redesigned, more efficient wide linkage and optimized spring tension combine for reduced shifting effort.
The front derailleur did not seem to have much change in shape, but upon closer inspection, there was a bit of tweaking to the design. A small change in the shape, and a couple of changes to the side plates. But the real proof was in the shifting, this was unbelievable. I have never felt anything like it before, it almost brought tears to my eyes. I tried it time and time again, it didn’t miss a beat. With just the smallest amount of force on the lever, it moved the chain up on to the big ring as if it was just a tooth or two difference. I got the other mechanics to try, just in case I was dreaming. They all were impressed with the shifting, just as much as I was. [Tech Ed: Drops no weight but does drop trim / indexing but say they’ve made it unnecessary. They also lower the spring tension to ease shifting.]
• RD-7900 Dura-Ace Rear Derailleur
Shimano Says: With a new carbon fiber rear pulley cage, the rear derailleur loses another 16 grams while maintaining durability and improving performance. The new design is compatible with wider range cogsets and can accommodate a maximum 28 tooth cog. The available wider range creates even better compatibility with compact cranksets.
The rear derailleur was dripping with carbon, the side plates and one of the pivots were looking decidedly stealthy. Even though I was told there was no change in the spring tension, they felt stronger. But this could have been the weight reduction giving the faster return action I could feel. A new set of pulley wheels, and a longer cage, made the chain run a little more freely through the unit. Shifting was just as good, a little snappier, but only slightly noticeable under load. Shifting up the cassette was much the same as before, but the down shifting, was a lot faster, and quite a significant change, perfect for the sprinters in the team. The combination of the cable coating, the lighter derailleur, and the greater spring tension, made shifting down as fast as shifting up the cassette, if not faster.
[PEZ Tech Ed: Longer cage, better shifting all round and 16 grams dropped.]
The Chain rings feature some aggressive new ramps.
The big chainring, half the weight, twice the strength, and hollow (made from 16 different pieces I was told). Had the most aggressive lifting ramps I had seen for a while on a road crank, very much like you would see on their mountain bike equivalent XTR. More forward facing teeth (though you couldn’t tell), and a new fixing system for the chainrings, were other new features. It has to be a mechanic’s design, but the new single bolt (torx bolt, threading into the outer ring from the inside) fixing method was a dream to work with. We were using our own SRM cranks on the bikes, and the rings fit perfectly, and easily. I am sold already on these, having numerous rings bite me bad, over the years.
The combination of the ramps, single sided chain, and the new lever, was enough anyway, I was hooked.
The ‘yet to arrive’ crankset now comes in regular and compact versions.
NOTE: – The full crank set was not available at time of writing, and Highroad received only the chainrings. Shimano reports “The iconic Hollowtech II hollow forged crank has always been a benchmark for strength to weight performance characteristics and is the perfect platform for a crank intended to be used at the highest echelon of competition. Combined with a hollow outer chainring the crankset is 20% stiffer for optimal power transfer while still saving 15 grams. Other changes include redesigned chainring teeth for better contact and power transfer. Improved bottom bracket seals further reduce contamination and friction.”
• CS-7900 Dura-Ace Cassette
Shimano Says: Shifting has been even further improved by creating an even more rigid (and lighter) aluminum carrier unit along with re-engineered teeth profile. Cassette design is lighter as Shimano has developed a super lightweight and rigid aluminum cassette sprocket carrier. The largest four cogs are titanium and weight is reduced by 10 grams. Available combinations will be: 11-21T, 11-23T, 11-25T, 11-27T, 11-28T, 12-23T, 12-25T, 12-27T.
The cassette has had a little bit of redesign going on as well. A bit lighter [T.E. 10 grams], and a little stronger, from what I saw. A few of the single sprockets, near the small end of the cassette had some cool lightening channels cut out of them. Likewise the cage holding the three sprockets at the back, had some machining done to lighten them as well. As to the actual difference in weight, I couldn’t tell, but they looked cooler though. Compatibility issues were our concern, as we only had 11-23, and 11-25 cassettes supplied. But as soon as we hit the mountains, the standard 27t cassette worked fine with the system, no adjustments needed. And the good thing was, when we implanted the compact cranks for the hilly TT, the chain worked perfect (not compatible with standard chainrings was the message from the engineers), with no compatibility issues at all.
The Gruppo also includes the new FH-7900 / HB-7900 Dura-Ace Freehub and Front Hub, and while Benny had no comments on these:
Shimano Says: Both the hub and freehub body have evolved to designs that improve rigidity for efficient power transfer and quick handling. The bearings have been updated with a new tool-free bearing adjuster for quick bearing adjustments. The freehub continues with the durable titanium shell and quick engagement internals.
Long Term Testing Report
After the month of testing, things still worked just as good. We never changed the cables, and they worked like a dream throughout. Both of the riders testing the groups were involved in a couple of crashes, and the gear survived well. In fact Tony Martin smashed his bike to bits in one of the early stages (I folded it in three, to fit in the back of the team car), and we were really worried about the shifters. But surprisingly they survived without a scratch, same as the rider. The chain wore out the same as the standard one, and the wear on the cassette and the chainrings was standard. I was pretty impressed overall, and like the new colouring of the official group published by Shimano. I have already ordered a set, now just to find a nice frame to hang it from.Я
Pez Tech Ed Adder: Well how’s that for an intro to the new D-Ace?! It took us a few days, but we got the High Road hands on and have been assured that this last testing phase were production spec items getting their final run through before full bore green light. So there’s general feel feedback and longevity and a bit of stuff on the shifting which we can verify (though we didn’t get a hand directly on the High Road stuff… Like Benny did).
The new stuff should get a short run of kits to the press possibly late July, OEM shortly after and Aftermarket I would guess in late September and early October.
BIG HUGE MASSIVE THANKS to Benny, High Road and Shimano for the info – !
• See more Benny online at Wrenchman.Blogspot.com
Available Fall 2008