I recently had a conversation with a bicycling friend that went something like this (I say "something like" because I don't record my conversations to have them transcribed verbatim). . .
Friend: "So, my friend that I do most of my riding with just got a new bike with electronic shifters. He really loves it. It's practically the same bike as mine except for the shifters so I can't wait to go for a ride with him and I can compare and see if he's really any faster than I am."
Me: "He won't be any faster."
Friend: "But I want to compare and then I'll know for sure."
Me: "He won't be any faster."
Friend: "But the guy at the shop says that the electronic shifting really is an improvement -- he says this is one upgrade that really makes a difference.
Me: "It CAN'T make you any faster."
So we go through this discussion round and round with me continually repeating that electronic shifting will not -- cannot -- make someone faster. If the rider is faster on a bike with cable operated shifters, then they will be faster with electronic shifters. If the rider is slow with cable shifters, they'll still be slow with electronics. How the bike is shifted has nothing to do with it. It doesn't even factor anywhere into the equation. The whole concept just seems typical to me given the hype that manufacturers, their marketers, and the typical bicycle publications lavish on the latest innovations.
Speed, of course, is primarily determined by pedaling cadence and gearing. Basic math. For a given gear ratio, the bike will move forward a specific distance for each pedal revolution. Multiply that distance times the pedaling RPMs, and you get a speed in feet per minute. Cadence is mostly impacted by the rider's fitness level. Gearing, in turn, is determined by the chainring/cog combination, wheel size, and crank length. Other factors that will affect a rider's speed would be: wind resistance; rolling resistance (affected by things like tire pressure, tire casing/construction, and tread); weight (I'd emphasize rotational weight first -- i.e. wheels -- then static weight -- i.e. frame, other components, and of course the RIDER); and drivetrain friction (affected by things like hub and bottom bracket bearings, chain+cogs+pulleys, etc.). Without doing a lot of research, I'd say it's a pretty decent estimation that those "other factors" are probably even listed in order of importance. Regarding weight, notice that I emphasize the rider. The rider himself (or herself) is far and away the single heaviest part of the whole equation, and is often the one thing the gets ignored in most discussions about bicycles and weight. Anyhow, reducing the various resistance, friction, and weight factors lets you either pedal in a higher gear or perhaps at a faster cadence than you might otherwise be able to, thereby letting you ride faster. Notice that there is not a single element in this whole equation that could be affected by the connection between the shift levers and the derailleurs.
One review that I saw of Shimano's Di2 shifters called them "The single most jaw dropping experience" that the reviewer had ever had. Phew! But the biggest benefit that I could see is that the front derailleur automatically "trims" itself (moves slightly to keep the chain from rubbing on the cage) when you shift the rear derailleur. Nice. If one primarily uses Shimano's cable-operated STI brake/shift levers, I can see that being a really nice feature -- mostly because STI doesn't really give a rider much control over front derailleur trimming. Campagnolo's Ergo levers are much better in that regard. Then again, NO integrated brake/shift levers give a rider as much control over that aspect as downtube friction levers, or even Shimano's excellent bar-end shift levers. With Shimano's bar-end levers, the rear shifter has solid, positive clicks between each shift. And the front lever has a super-fine ratcheting mechanism that allows virtually infinite fine-tuning of the front derailleur position. Not only that, but I find that, with a little practice, I can shift the rear derailleur with my right hand while simultaneously trimming the front derailleur with my left. No problem. With downtube levers, I can do the same thing with one hand -- and that's not bragging -- I'm assuming that most riders who cut their teeth with downtube friction shift levers can probably do the same.
Another review of the Di2 system said that the shifting was so slick and reliable that it would let the rider "take his mind off the shifting and focus on the ride." OK. Here's the thing. If someone is so preoccupied with their shifting that it takes away from their ride, then I'd argue that they have bigger skill issues than what can be solved by switching to electronic shifting. Are botched shifts really that much of a problem?
(WARNING: I'm entering full-on Retrogrouch mode here)
I have a few bikes with friction downtube levers, one with Dura Ace bar-end shift levers, one with Shimano STI controls, and two more with Campagnolo Ergo integrated levers. The controls that probably give me the fewest problems in shifting are the bar-ends. They just work. Every time. Even if the system gets a little out of adjustment, they still work because their tolerance for maladjustment is just that high. With the integrated brake/shift lever systems (STI and Ergo), the biggest problem that I've ever encountered would not be solved by switching to electronic controls. It's a total newbie mistake that doesn't happen often, but I always feel like a complete dork when it does. Here it is: I push the lever or button to downshift when I actually want to upshift. Or vice-versa. In my own defense, I'm most likely to do it after I've logged a bunch of miles on a bike with down-tube or bar-end levers, then switch to one with integrated levers. And also it's worth noting that the levers or buttons that control upshifts and downshifts on the left side (front derailleur) do the exact opposite on the right side (rear derailleur). Switching to electronic shifting would not prevent that dumb mistake -- but I suppose it's really nice to know that the electronic system would still flawlessly and reliably make the shift happen anyhow.
Pretty much all the other benefits -- like being able to shift the front derailleur while standing on the pedals -- seemed pretty minor to me, especially considering the huge price difference between the cable-operated vs. electronically controlled components. It varies from retailer to retailer, but it's roughly $2000 difference between "traditional" and "electronic" for Dura Ace. Ultegra Di2 can probably be had for about $1000 less than the Dura Ace version, but still many hundreds of dollars more than the "traditional" set. Will it get cheaper over time? Probably. In fact, it was hard for me to figure out just how much the Di2 stuff actually costs because prices between different online retailers seem to vary so wildly. Some retailers offer some pretty drastic discounts (which should really tell you something).
|List price $139|
|List price $469|
|List price $759|
|List price $279|
One can find similar price differences between the Campy versions, too. But overall, given how well many of today's traditional components work, I just don't see where the benefits really justify the cost. Add to that the bloated-looking electronic components (compared to their "traditional" counterparts -- as described in previous posts), and the tumor-like battery packs and control units, and the need to keep them charged (and what I presume would be the inability to shift should you forget to do that) and the fact that there is probably nothing in these electronic component groups that is going to be user-serviceable, then I just don't see the point in making the switch.