All a coast down test does, Jay, is show which bike is lower to the ground and weighs more.  Looks at your results and it becomes obvious.  Most B riders I ride with ride much more reclined but they rarely beat me down the hills unless they crank.  My fat butt overcomes a lot!   But all that mass has to go right back uphill, and now we're talking about weight again, in reverse.  I bet if you did a lot of hill CLIMBS your results would be based purely on weight.  However, a mile of cruising on flat ground at the same wattage will tell you a lot more about true power to the pedals.
 
Powertaps can be had relatively cheaply compared to the cost of the bikes in your stable  .  You'd only need 1 in 650 and 1 in 700.  Dana had a special for the hub at 699.  Mount them both to the same cheap wheel.

Quote from aikigreg on Aug 2^nd, 2011, 9:43pm:

 
Greg, from what I understand drag starts to become the most significant factor in resisting forward movement at 15 mph and over (that's why I did running starts at about 15 mph in my test runs). If conducted properly, coast down tests should reveal the most aero recumbent to the least in order. The most aero should require the least cranking effort at say 23 mph on the flats. In my case (My Carbent and I weigh a total of about 168 lbs) I pass heavier, tucked roadies, in high-speed coasting down steep hills. This can only be attributed to superior aerodynamics.
 
I'm an older rider - new bikes, not expensive power meters and associated computers, are on my bucket list.    

Again I will remind you, Bud, the weight (or mass) of a falling object does not appear in the equation for acceleration due to gravity.  Thanks to that meddling Italian, Galileo, we have to face it, that gravity only works against us, not for us.  

Hey jay, here something you can do and only you because of your unique setup and tested. Take your fastest bike duplicate the same test but add weight like 50 lbs without restricting the airflow or aero of the bike and see what up..

Quote from johnnybent on Aug 3^rd, 2011, 3:36pm:

 
Best answer all thread!!!!  Jay you gotta quit buying those black bikes - that is why i'm kicking your butt on the actionbent!  

Quote from johnnybent on Aug 3^rd, 2011, 3:36pm:

 
You have two fast red bikes, but I never see you on them. Still think you have them hung from the ceiling of your apartment as mobiles.  

Quote from Bud_Bent on Aug 3^rd, 2011, 1:30pm:

 
Bob M, I think I'm going to have to part way with the Galileo argument and agree with Bud. Spent the whole day researching this question (I've said before that I have a lot of free time  ) until my head was about to explode. This question about weight affecting downhill speed has been discussed in many articles and forums with many people taking opposing positions. I refreshed my memory of inclined plane dynamics and found that acceleration of a rider down a uniform slope is equal to the force component parallel to the slope (This force component includes a portion of the rider's weight, minus rolling resistance, minus an increasing drag force) divided by the rider's mass. So, weight of the rider plus the bike does make a difference.
 
Here is an excerpt from one of articles I found: "Thus, the terminal velocity is roughly proportional to the square root of the ratio of M/A. Scaling reveals that larger cyclists have a greater ratio of mass to frontal area. They therefore descend hills faster as a consequence of purely physical, not physiological, laws. Since the larger cyclist has a greater mass, gravity acts on him or her with a greater force than it does on a smaller cyclist. (Note: A common misconception is to note the equal acceleration of two different sized objects in free fall in a vacuum, and assume that the force of gravity on both is equal. The force on the more massive object is greater, being exactly proportional to mass, which is why the more massive object is accelerated at the same rate as the less massive one.) While the larger cyclist also has a greater absolute frontal area than the smaller cyclist, the difference is not as great as that for their masses. Thus, the larger cyclist will attain a greater s3 before a balance of forces results in terminal velocity."
 
Regarding the question of whether or not my lighter bikes should have been ballasted, so all of them would have been of equal weight - The weight difference between the lightest and heaviest is 13 pounds. Might have been a good idea to do that.
 
Hope this puts an end to the discussion. My head hurts.