By Jim Weaver, Service Manager, Fit Werx, VT
Note: As of 8/3/14 firmware updates from Shimano remove the functionality between 6770 and 6870/9070 electronic components being used together. Some previous firmware versions allowed the below conversion to function without replacing the front derailleur, but firmware being installed as of 8/3/14 will irreversibly render such a mixed system dysfunctional. As of 8/3/14, a 6870 front and rear derailleur are both required to allow 6770 shift levers to work with an 11 speed cassette.
The Shimano 11 speed Dura Ace 9070 Di2 system was released in the spring of ’13 to resounding accolades. Over the winter, Shimano has released the new updated Ultegra 6870 Di2 system for 11 speed. I have had the opportunity to install this component group on several bikes. Of course Dura Ace 9000 has the usual advantages over Ultegra, such as lighter weight, nicer finisher, and better bearing surfaces for longer life and smooth operation. However, functionally, the two groups are very close and share all the same battery packs and wiring. Simply stated, the new Ultegra 6870 Di2 system works great. It has the same programmability as Dura Ace and is a great option for someone looking to save a few component dollars while still taking advantage of Shimano’s electronic Di2 system.
The introduction of the full Di2 11-speed line from Shimano raises the question of whether the previous generation Ultegra 6770 Di2 10 speed system can be ungraded to 11 speed compatibility without replacing all the components. The simple answer is, “Yes”. Di2 shift levers are little more than buttons and thus they don’t differentiate between 10 and 11 speed the way a mechanical lever does. However, some parts will need to be changed if you want the system to actually function…
When it comes to the actual drivetrain, the limiting factor for the 6770 generation Ultegra Di2 system working with 11 speed is the rear derailleur. The Ultegra 6770 Di2 rear derailleur (top image below) will not recognize 11 speed shift commands. However, all you need is a new Ultegra 6870 (or Dura Ace 9070) rear derailleur (a 32T compatible version is pictured in the lower image), a new 11 speed cassette, and a new chain and the rest of your existing shifters, cabling, junction boxes, front derailleur and brake calipers will work just fine. (Note: As of 8/3/14, there are front derailleur firmware compatibility issues. See top of post).
It is worth noting that another potential limiting factor is your rear wheel. A new 11 speed Shimano or SRAM cassette will not fit on many older 10 speed freehub bodies and some hub designs cannot be updated. Most new road rear wheel is now equipped to accept an 11 speed cassette, so if you are getting new wheels this shouldn’t be a problem. Older wheels may, or may not, be able to be adapted by replacing the 10 speed freehub body with a new 11 speed part – it depends on the wheel, so check with us. We can tell you that if you have a Mavic rear wheel, you are likely in luck, as no replacement pieces are needed at all. We simply remove a spacer that was required for your 10 speed cassette, and Viola! 11 speed compatibility. Unfortunately, their freehub is one of the only ones that is this easy (or free…) when it comes to using an 11 speed cassette.
So, if you have an Ultegra Di2 10 speed system now, and are hankering to add another gear to give you more shifting options or to bridge a gap in your current cassette; or if you want to start using one of Shimano’s new 32 tooth cassettes, it is actually not that difficult. As an added bonus, if you buy the parts through Fit Werx and mention this article, we’ll install them for ½ the normal labor rate! Contact us for more information…