Originally Posted by
cplager
First, it's the mass (and really the distribution of the mass) that matters; not the radius (if you do the full calculations with moment of inertia, etc, you'll see that the radius of the wheel drops out of the equations). Now, bigger wheels are generally heavier, so it's almost true that bigger wheels are slower.
Nope! Both mass and radius are important.
Second, the bike isn't just wheels. When you accelerate the bike, you've got to get you and the whole bike moving. And you are much heavier than the wheels (even if you're tiny).
But that would be true, regardless as to which wheel we're talking about! All other things being equal, the larger wheel should be heavier. Therefore, it will have more weight and be harder to speed up or slow down.
As far as that article goes, the author says many things in the article that are wrong (e.g., smaller wheels are easier to accelerate, bigger wheels have bigger contact patch). The author's degree is in psychology, not physics or engineering, but that's not really a good excuse.
What do you mean? ...Those are all facts, given the same tire width!
You'll also hear exactly this in a lot of bike shops: Dude, spend money, get the lighter wheels, you'll accelerate faster. I don't think they're lying just to sell you wheels. But they're still wrong. (Aerodynamic wheels, on the other hand, will help you go faster.)
Lighter and more aerodynamic wheels will help you to accelerate and maintain speed, both by decreasing air friction and having less mass.
Tom Sarazac explains the wheel diameter thing best:
www.tomsarazac.com/tom/opinions/wheelsize.html