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I think somewhere between .30, and .35 is a pretty good approximation for craig's bike. this is basically a blunt somewhat smooth body with good profile. the open sides act like open windows or wheel wells on a car. only creating a deceptively small amount of turbulence. Allert's would probably fall between .25, and .30, and looks to be quite a bit lighter. Also rolling resistance would be just over half the average for a car. this accounts for higher resistance tires, but half the number of tires. you must also figure that we are not using 100% of our rated output at 70mph. why? we could ride 70 all day without killing our bikes. 100% output will damage an engine after a relatively short period. The most efficient design would use about 60-70% load with the lowest drag possible. also, my bike is rated at 12-14hp new and is 30 years old. I was probably using closer to 10hp on the 70-80mph section, and making it up on the slower parts using closer to 5-6 hp. Craig's bike is rated at 16hp, and could go 70-80mph. this means that either the calculator is wrong, or that Craig's design is better than you give him credit for.
For the record, my frontal area was quite a bit less, but I think my cd is slightly higher.
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