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Step 1:

Put your bike in a workstand. Shift into 53 x 15. Now turn the cranks by hand until you reach 100 rpm. You can start in a lower gear if you want and shift up, just make sure neither the rear wheel nor the cranks are moving when you start. Time how long it takes to get to 100 RPM in the 53 x 15, and notice how much effort it takes. Not much, right? You did it with one hand and aren’t even breathing hard. You rear wheel is now spinning at 353 RPM, equivalent to about 28.4 MPH.

Step 2:

Take your bike outside and accelerate from a dead stop to 100 RPM in the 53 x 15 (again, about 28 MPH). Try to do it just as quickly, i.e. in the same amount of time, as you spun up the cranks in step 1. That was a lot harder, right? If you could do it at all, chances are it took all the power you could produce with both your legs, and your heart rate and breathing are now very rapid.

You accelerated your cranks, pedals, and rear wheel to the exact same rotational speed in steps 1 and 2. (OK, the front wheel wasn’t spinning in step 1, but you get the point. I hope.) The difference between the two efforts is the force required to accelerate the total mass of your body and bike, plus overcomong air resistance. Overcoming the polar moment of inertia of your wheels is trivial by comparison.

I have no axe to grind with this, and if you still want to buy a lighter wheelset, go right ahead. I just think we will be smarter consumers and better riders if we stop believing in fairy tales and start applying science to our training and equipment.