Mark Purdy just got trained on Campy’s new EPS electronic shifting system. He’s also installed a few Ultegra Di2 units already, so I stopped by his shop and got the lowdown on the current state of electronic shifting.
Purdy's iPhone shot of the gruppo. Wait, there's a cable!
Purdy’s overall impression of EPS is that it’s better crafted than Di2 – everything feels more solid, and the shifts sound less chirpy. Campy measured the throw and resistance on their cabled shifters and replicated the feel for EPS. The thumb shifter has rotated down on the shifter body so it should be more accessible in the drops, but otherwise it feels just like the cabled system. To Purdy, it just ‘feels right’.
EPS can only be internally routed. If your bike is made for cabled shifting you won’t be able to install EPS on it. Not that it matters, since there will be no aftermarket sales for quite a while – if you want to get it fast you’ll have to buy a complete bike.
The system is waterproof to 1 meter – it’s said to have been tested for hours submerged in a tank of salt water. The connections are waterproof and can only be undone with a special tool...that doesn’t exist yet. I guess it’s just as well there’ll be no initial aftermarket sales. If someone connects the wires before routing them through the bike they’re screwed.
There are anecdotal stories of Di2 temporarily shorting out in torrential rains. EPS should prove to be more robust, especially for cyclocross.
Battery life is about half to a third of Di2, about 2000k. The battery and the brains of the system are one unit, and never come off the bike. You plug into the battery to recharge it. If you crash or drain the battery you can disengage the motor in the rear derailleur and manually set it to a cog. The derailleur just stays on whichever cog you choose.
Initial setup is easier on EPS. You only need to set the inner limit for both the front and rear (you have to set both on Di2). The system knows where everything else should go from there. Adjustments are made by hitting specific sequences on the shifter buttons.
An indicator strapped to the stem tells you what mode you’re in with colored lights. Unlike Di2, it has no buttons. The rear derailleur is tweaked .1mm per click, compared to .25 for Di2. The precision of EPS is a perfect match for 11 speed, which can be finicky with cables.
The front derailleur shifts with 50Nm of force. For reference, cranksets are installed with 35 Nm of torque. Like Di2, a small metal plate is glued to the seat tube for the derailleur to push against. Shifting under load should be, like Di2, no problem.
There will be no bar top or sprint shifters – apparently Shimano owns the patent for auxiliary shifting positions. TT shifters are being developed. It’ll be interesting to see if there’ll be just one shifting position for EPS TT bikes – the ability to shift in and out of the aerobars is one of the best features of Di2 on a TT bike.
You can press and hold for multiple shifts, but Purdy thinks this is a useless feature. When you press and hold, EPS will first make one shift, then wait a beat before sweeping through the gears. Purdy found that it was quicker to just tap the shifter as many times as you need.
Here's that mysterious cable again. It has rare earth magnets on its ends to facilitate internal wiring.
Wiring is vastly improved with Ultegra Di2. In fact, the next generation Dura Ace Di2 will adopt Ultegra’s wiring system. All the wires are interchangeable, you simply spec the length of each wire to suit your bike and its routing.
As you can see, Purdy is already fully stocked with multiple lengths of wires.
Ultegra’s derailleur motors are off the shelf items, so both the front and rear derailleurs are significantly bigger than their Dura Ace counterparts.
The shifters appear identical to Dura Ace with the exception of aluminum instead of carbon levers.
Like Dura Ace, the rear derailleur has manually set upper and lower limits.
In general Purdy likes Ultegra Di2. It's heavier and cheaper, but from the rider's perspective there is no real difference between it and Dura Ace. And Purdy wouldn't buy Dura Ace Di2 now. The 2013 changes to its wiring will make the current version obsolete fast.
Is electronic shifting a scourge or a godsend? Either way, Purdy thinks it is here to stay. Cabled shifting won't be obsolete, but for the foreseeable future electronic shifting will be the top of the line for Campy and Shimano. It’ll get lighter, smaller, better, cheaper, and more widespread, and eventually all pro teams sponsored by the big two will be on it.
For more info on Dura Ace Di2 check out this build with Purdy.