Originally Posted by Az B
I see where we're failing to communicate. You are looking at the drivetrain as the entire system. And yes, it is slightly more efficient.
I'm looking at the whole package. With 1/4 to 1/2 horspower moving around 200 lbs of weight over mixed terrain, multiple gears allows the motor to be far more efficient with a slight loss of drivetrain efficiency. Think in terms of calories used per mile.
Az
It occurred to me after making my post that you were likely talking about the entire system. Generally speaking, when people talk about the efficiency of one bicycle versus another, however, they seem to be talking about the mechanical efficiency of the drivetrain. I don't think I've ever heard anyone claim that it is somehow more efficient, in terms of Calories per mile or any other measure you can think of, to run a singlespeed drivetrain. What is generally referred to is how easy is to push, for example, a 75 inch gear on a SS versus a geared bicycle. The claim is that you can run a push a slightly higher gear at the same cadence for the same amount of effort, thereby moving a bit faster in that particular gear on the SS versus the geared bike. This is a reasonable claim, and I believe that it is what
most folks mean when they talk about efficiency.