Now to the riding:
The group has snappy, accurate shifting, albeit perhaps louder and less smooth on rear upshifts (to smaller cogs) than Shimano Di2, but it has better ergonomics. EPS would work great in the cold with thick gloves, while Di2 is less than ideal in that situation; its two buttons are close together and don’t make the same kind of distinctive clicks that the Campy ones do, so it’s easy to shift the wrong way or not at all with Di2 and winter gloves.
The sound of the high-speed (12,000 RPM with EPS) servo motors driving the derailleurs is almost identical to Shimano Di2, as is the action of the chain. As with Di2, the front derailleur automatically moves over to avoid chain rub on the front derailleur as the rear derailleur is run through the gears.
The difference between the two systems really lies in the feel. Besides obvious differences in lever shape, the distinctive click of each shift with EPS feels similar to the click of a cable shift (it requires much less finger or thumb movement, however), whereas the button push is much less noticeable with Di2.
Campagnolo achieves this feel with its “MultiDome” switches — layers of domed spring steel under the lever require two kg of force to compress them and activate the switch below. The lever provides so much leverage that the force from the finger is much less, but the click and feel of the button depressing is quite distinct.
The “Virtual Hand Sling” with EPS
The front shift from small to big front chainring when sprinting out of saddle over the top of a hill that I love so much on Di2 is also possible with EPS, but the shift is slightly less powerful and quick than with Shimano’s electronic front derailleur.
When pedaling moderately hard out of the saddle when cresting a hill in the small chainring, if you hit the left EPS upshift lever, it pushes the chain right up to the big ring, although it is sometimes slightly delayed while it waits for the next chainring shift ramp to come to the top.
But when I was sprinting full out in the small ring over the top of a hill and hit the upshift button, there was a considerable delay before the chain went went up. It still shifted and gave me that feeling of a hand sling and an immediate gap over my proximal riding partners, but the delay was a bit more than ideal.
With Di2, upon cresting a steep hill, if I hit the upshift button on the left lever under full power just as my cadence increases, it consistently, instantly, and smoothly ramps right up onto the big chainring.
Like Di2, one of the ways that EPS manages such a hard shift under load is by overshifting (and it overshifts a different amount depending on which rear cog the chain is on), and then returning to center over the chain once the shift has been completed.
With both Di2 and EPS, no concentration and minimal hand force is required to get this “virtual hand sling” over the top of a hill — just a tap of a button. The acceleration is amazing; to be suddenly going full out atop a big gear without having eased off to make the shift is quite the sensation.
In case you are wondering, you cannot make this shift effectively with cable-actuated systems, because they cannot shift under as much pedaling torque as either Di2 or EPS. I know, because I’ve tried it many times on bikes equipped with 2009 or later Dura-Ace 7900, SRAM Red, SRAM Rival, Campagnolo Super Record, and Campagnolo Centaur.
While there are variations in how each system accomplishes the shift, I have never been able to achieve the same sensation with any cable-actuated system as with the electronic ones.
The full-shift through all 11 cogs in either direction I mentioned yesterday, or through as many of the cogs as you choose, by holding down the shift button, is really sweet. Cresting a steep climb and dropping all 11 cogs from biggest to smallest is great, but it turns out to also be easy to just go through, say, just three or five cogs. I had worried that you would have no sense of how many gears you were shifting and when to stop pressing the button, and that it might continue shifting after you let go, but none of that turned out to be the case. My legs told me right away when I had shifted through as many gears as I cared to, and when I let go of the button, the shifting ceased instantly.
Campagnolo claims that the average shift speed is about a third of a second, while it is about a half a second with its cable-actuated systems, and that the entire 11 cogs can be shifted in 1.5 seconds.
In case of emergency: If the derailleur is hit in a crash (and indeed, one of the riders today managed to crash into a wall and do that — he was OK), it protects itself by uncoupling the electronic motor from the mechanical shaft. You’ll know this has happened when it won’t shift to the smallest cog. To re-couple it, you can repeatedly press the upshift button without pedaling until it hooks up and will again allow shifting to the smallest cog, or you can stop and engage the two parts by pushing inward on the derailleur body with your hand until you hear it click back into place. This uncoupling feature can be used to set the rear derailleur on any cog to ride back home when, for instance, the wire has been cut in a crash, or the battery has been completely discharged.
Power down: The system can be shut off for transport or when leaving it for extended periods without riding, to prevent discharging the battery. This is accomplished by inserting a magnet into a small hole in the battery pack.
On the road adjustments: Front and rear EPS derailleurs can be adjusted on a stand or while riding (such as when you’ve taken a spare wheel during a race). Adjusting the front derailleur is simply done on the small-big combination, by bumping the lever while it is in the adjustment mode until the inner cage plate is 0.5mm from the chain. Adjusting the rear derailleur is done by bumping the shift buttons in the adjustment mode until it is quiet on the second largest and second smallest cog. Furthermore, the standard inner limit screw (to keep the chain out of the spokes) and b-screw (to adjust the distance from the cogs to the jockey wheels) adjustments apply as well. Vuelta stage winner Pablo Lastras of Movistar said that he never readjusted his rear derailleur the entire season and used many different wheels on his bike.