My wife and I have been riding together for a number of years now. We’re at the point where we ebb-and-flow together on the road without even thinking about it. As long as we’re on our usual bikes (a pair of Rivendells), we can ride for hours without either of us needing to say a thing about the pace.
It’s always interesting though, to bring a new bike into the mix. Because she rides her trusty Betty Foy most of the time, and we ride together so much, she acts as a baseline against which I can gauge the relative efficiency of any new bike we have on hand.
My new Civia is a good example. I rode it alone on my commute for two weeks before riding it with her on a weekend for the first time. I had pretty well convinced myself that it was less efficient than my Rivendell. I’m not 100% sure why I came to that conclusion, but it probably had to do with the general consensus that internal gear hubs are less efficient than derailleurs, and that the internal gear hub concentrates weight at the rear of the bike, making it feel heavier than it actually is.
Much to my surprise, on that first ride she had some trouble keeping up with me (if anything it’s usually the other way around). I kept finding myself absent-mindedly cruising along at what felt like our normal pace, then looking back to see her falling behind. It finally dawned on me that it was the bike. Subsequent rides on those two bikes confirmed my suspicion; in their current configurations, the Civia is more efficient than the Rivendell.
After thinking it through, this all makes sense. As we all know, a large majority of the effort we expend propelling a bicycle goes toward overcoming wind resistance. In the case of these two bikes, the Rivendell is set-up to place me in a comfortable, upright position. The Civia, on the other hand, has lower bars and a longer reach to the grip area which places me in a slightly less comfortable, but more aerodynamic position. I believe this difference in rider position explains the Civia’s higher efficiency, even with its potentially greater rolling resistance due to the internal gear hub and heavier tires. I’m pretty sure that reversing the cockpit set-ups would make the Rivendell at least slightly more efficient than the Civia.
Of course, none of this is anything but totally subjective. But I suppose that’s the point. We can make all kinds of assumptions about the efficiency of a bike based upon our pre-conceived notions regarding drivetrain efficiency, weight, handlebar height, etc., but it’s all conjecture until we get out on the road and see how a bike actually rolls along in a familiar setting.