SHIMANO ULTEGRA Di2 – A QUICK REPORT

SHIMANO ULTEGRA Di2  – A QUICK REPORT

By Jim Weaver, Service Manager

Fit Werx, VT

I just finished building two bikes with the new Ultegra Di2 electronic shifting group.  One bike is a very nice Serotta Ottrott SE.  Saying an Ottrott SE is “very nice” is redundant, as I cannot imagine an Ottrott that is not “very nice”.  But I digress.  The other bike I finished is a Cyfac Spirit, with internal cable routing specific to Di2.  Cyfac may be an unfamiliar name to riders in the United States; they are a custom frame manufacturer from France that builds using carbon fiber, titanium, aluminum, and steel, in a very wide variety of frame designs.  The Spirit is one of their steel offerings and we were impressed with the quality and finish and we liked that it was a bit out of the ordinary.   Well, “out of the ordinary” is really not the right term; Serotta, Parlee, Guru, Independent Fabrication, Seven, or Moots, other hand built manufacturers we represent, are definitely not “ordinary” bicycles.    Perhaps I should use the adjective “rare”, “scarce”, maybe even “esoteric”, rather than “out of the ordinary”.  The bottom line is that if you are riding a Cyfac, odds are that you will have the only one on that next group ride.  But again, I digress.

The topic at hand is a first report on the Ultegra Di2 group.  From a mechanic’s perspective, the electronic group goes together fairly easily, arguably slightly easier than with Dura Ace Di2.  If the bike has internal cable routing, the Ultegra Di2 is much easier to build than the Dura Ace as the cable junctions for Dura Ace require the use of heat shrink tubes around each joint to make them water-tight.  The Ultegra connections are water-tight without the need for any additional sealing.  This is much easier for me, the builder, not to have to mess with using a heat gun, in tight spaces, around painted surfaces.  Presumably Shimano will adopt this type of connection on the next generation of Dura Ace components.

The setup and operation of the Ultegra is the same as the Dura Ace.  Initial alignment of the derailleurs is very easy, and the process is the same for both groups.  I did not notice any difference between the two when riding.  Shifts are spot on, no misses because you did not swing the lever far enough, and are totally predictable.  The front shifting is of particular note, being very quick, no misses, no rattling, and with the entertaining and functional computer controlled automatic trimming to prevent the chain from rubbing the derailleur.  These same comments apply to Dura Ace as well.  The only drawback I see to Shimano’s electronic shifting is the inability to shift more than one cog at a time, but if you move your finger rapidly this doesn’t seem like much of an issue.

Unfortunately, my rides of both Di2 systems have been limited to brief test rides of new bikes to insure that everything is working properly, and that the build of the bike is correct.  Perhaps back-to-back, longer rides would reveal operational differences between Ultegra and Dura Ace that I could not detect.   It is worth noting that there are some other notable “non-operational” differences between Ultegra and Dura Ace Di2.   All of the Ultegra parts, particularly the front and rear derailleurs, are noticeably heavier than their Dura Ace counterparts – 263 grams, about half a pound.  For high performance bikes these days, half a pound is a lot.  This being said, the Ultegra Di2 is only 80 grams heavier than the mechanical Ultegra group, so the weight penalty for going to electronic shifting is minor.  The Ultegra Di2 derailleurs are also larger and bit chunkier in appearance than their Dura Ace siblings.  The primary reason for the bulkier look is that the Dura Ace derailleurs use motors designed by Shimano specifically for that application while the Ultegra derailleurs use “off the shelf” motors in order to achieve significant cost savings.  I do not find the larger, bulkier look of the Ultegra to be a significant detraction, but they don’t appear quite as refined.  The battery is the same lithium ion battery as used in the Dura Ace group, and the battery life is predicted to be the same.  Shimano says the battery should last at least 1,500 miles.   Recharge takes 90 minutes, and the battery can be recharged 5,000 times.  That’s a lot of miles!

Simply stated, everything you have read about the Dura Ace Di2 operation applies to the Ultegra group.  If you want the ultimate, go with the Dura Ace for its lighter weight, better esthetics, and all the durability and bearing quality advantages that Dura Ace components offer over Ultegra in the long-term.  On the other hand, if you want the benefits of electronic shifting for half the price of the Dura Ace group, Ultegra Di2 offers a lot of “bang for the buck” and will likely be very popular over the next few years.