’09 Dura-Ace 7900: Fresh spy photos & updated info.
Patience is a virtue, and the long spring of waiting has culminated with the following new info: The new-for-2009 Shimano Dura Ace 7900 should start having some availability in late October. You might see it on an OE-basis (i.e. equipped on pre-built bikes) a bit earlier. But for aftermarket availability, we’re looking at October-at-best. The electronic version — which is really just three components (shifters and derailleurs) is more like best-case-January 2009.
Here’s what we DO know (including weights!) on a component-by-component basis:
- Say farewell to exposed shifter housing. Shimano is making the change to under-the-bar-tape cable routing They refer to it as ‘integral shift cables’. We wonder if Shimano-sponsored pros will find digging deep on the front a but tougher without shift cables to grab on for stability…
- ‘A new perch shape.’ Our interpretation of this means that the shape of the brake hood will be different. We’ve never enjoyed the deep hook of DA brake hoods, and to our ears it sounds like Shimano is modifying the shape to make it more SRAM/Campy-like. In other words, no more plunging hook, and instead you’ll see a flatter hood. Beyond the ergonomic improvement, Shimano also claims this leads to smoother braking.
- You get a reach adjustment mechanism. This is a nice feature of SRAM Red, as well. Folks with small hands should be very pleased.
- 20% shorter stroke to achieve shift engagement on the right lever.
- Weight savings thanks to the use of a unidirectional carbon brake lever and a titanium fixing band & bolt.
- The brake cable pivot location is moved to give better braking modulation.
- 378g for the set — that’s 40g lighter than DA 7800.
- Carbon! The pulley cage will be made from carbon fiber. Shimano is a company built on their commitment to the forging of alloys, so any sort of branching out into composites is a big, big deal.
- Increased chain wrap capacity. In other words, you can use a wide range of gears (e.g. a 50/34 & an 11/28) without having to resort to a ‘Triple’ rear derailleur.
- You get an ‘enhanced pulling cable method’ with an audible click when the shift is complete.
- 166g — that’s 16g lighter than DA 7800
- Due to its redesigned cage profile and linkage, Shimano claims that your days of trimming the front derailleur are over. No trimming will be required. This is a pretty big coup when you compare it to SRAM, since one big upside of Red (in comparison to their Force and Rival gruppos) was its inclusion of FD trim.
- The FD spring tension has been re-tooled to achieve ‘featherlight downshifting’.
- 68g — that’s 6g lighter than DA 7800.
- Put aside your sugar-plum visions of a DA Carbon crankset. Rather, Shimano has forged their 7900-series aluminum crank with even thinner walls to make it lighter than any production carbon crankset in the marketplace. Despite this lightness, though, Shimano claims the 7900 will be 20% stiffer than the 7800.
- When you use the 7900-series crankset with the new 7900-series chain, you’ll get no front derailleur rub thanks to its new chainring/spider design. This also allegedly provides improved power transfer, thanks to the superior mating of chain and chainring.
- More weight savings comes from its new aluminum/carbon composite BB axle.
- Shimano will also introduce a 7950 version of the crankset, with 50/34 chainrings. This will be the first-ever Dura Ace compact crank (a full, what, 7 years since FSA introduced theirs?)
- The crankset will be 15g lighter than the 7800, and including the bottom bracket you’re looking at a total weight of 725g for a 170mm crank/BB combo.
- The 7900 chain is known as the ‘Super Narrow’ chain. The redesigned outer plate resists chain suck, and the new design of both the inner & outer plate mesh with the chainrings with such precision that Shimano claims it reduces mechanical friction by 0.6%. We’re a bit unsure how to parse what that 0.6% converts to…Does that mean an extra 2.4w when you’re making a 400w effort? We’re unsure, and we’re eager for a fuller explanation. Perhaps more important is the fact that Shimano also says it’s a quieter chain.
- The 7900-series chain has hollow pins and perforated plates to further reduce weight.
- The outer plate redesign is intended to reduce chainsuck. The inner plate redesign is what reduces your drivetrain friction and gives you that bit of extra drivetrain efficiency.
- Shimano will introduce a ‘Quick Link’ for its 10-speed chains. Our impression is that this means tool-free installation. However you CAN still use an HG pin if you prefer.
- 252g – 18g lighter than DA 7800.
- Like the chain and the crankset, the cassette sprockets get fine-tuned to optimize shifting, and the cog carrier is a lighter-than-ever aluminum.
- You’ll see a wider array of cassette ratio options. In addition to all of the options you get in 7800, you’ll also see an 11/25, 11/27, and an 11/28. Before you laugh at the 11/28, keep in mind that this is SRAM’s #1 selling cassette ratio! All the ratios made in the 7800 will be produced as 7900-series models as well.
- The aluminum carrier unit is redesigned to make it more rigid & lighter.
- 163g – 10g lighter than DA 7800.
- Gets revised caliper arches to ‘improve linear feel’ and the modulation of the brakes. We think this means you’ll get quicker caliper response when you hit your brake lever, and perhaps better stiffness under heavy braking.
- Lower profile outer cable stop. This improves cable routing, which decreases drag and improves the snappiness of the lever. If you’ve ever installed a set of Zero Gravity brakes, you know that fine-tuned brake cable routing is something you should never take for granted.
- The brake pad compound changes. Shimano claims that the improvement will be most noticeable in the wet, where stopping power improves dramatically, though get a noticeable improvement in the dry as well.
- Add’l titanium hardware saves overall weight.
- 293g per pair — 30g lighter than DA 7800.
Flight Deck Computer
- It’s still integrated into the STI levers, but the functionality gets much broader — It includes a heart rate monitor, altimeter, and an inclinometer. It’s a full-on 2.4GHz wireless system, and you can even download data wirelessly onto your PC.
A Final word on compatibility between Dura Ace 7900 and Dura Ace 7800