Here in Vermont we have a lot of mountains (no kidding!), and roads that go up and over those mountains. Gearing is thus a major concern for many of our clients. From items like wide range aftermarket cassette cogs to J-Tek pulleys and Wolf Tooth RoadLinks, we work diligently to be aware of the latest options for a variety of drivetrains and how well they work.
One of the most common requests for lower gearing we get has been for Shimano’s Di2 system. While the latest generation Ultegra 8020 and 8070 goes to a 34T large cassette cog out of the box (and we’ve seen more than a few people run 36T), Shimano’s previous two generations of components were not so generous in their gearing. Shimano’s two generations of Dura Ace Di2 road rear derailleurs (7970 and 9070), and the first generation of Ultegra Di2 (6770), could only safely be used with cassettes equipped with a largest cog of 28 teeth. While you can read on-line about people getting them to work with 30 teeth, using some sort of jiggery-pokery, these usually only work under some limited conditions and the risk of the derailleur being ripped off the bike accidentally increases markedly. Ultegra 6870 Di2 officially increased the cassette capacity to 30 teeth and I have had good luck with cassettes up to 32 teeth. However, this may still not be as low as you want and thus you are out of luck putting low gearing on the previous two generations of Di2 components. K-Edge to the rescue…
K-Edge has developed a replacement rear derailleur pulley cage for 6870, 6770, 7970 and 9070 Di2 rear derailleurs that can accommodate cassettes up to 36 teeth. I wrote about this conversion at https://fitwerx.com/index.php?s=K-Edge, and we have had this conversion performed by K-Edge for many clients to date.
One limitation of the K-Edge Long Cage Conversion Kit was that the derailleur had to be shipped to K-Edge and thus the turn-around for this conversion was 2 to 3 weeks. Given the delay, it was not something we could offer on a “while-you-wait” basis. Today, we can do the K-Edge Long Cage Conversion Kit in-house; send us your derailleur and we can install the kit and send it back to you. We usually install and send back derailleurs within 48 hours of receiving them.
If you have an older Shimano Di2 system and want to lower gearing, we can now take care of you in-house. Contact Us and start spinning up those hills with (relative) ease using a K-Edge long cage rear derailleur conversion!