Originally Posted by
3alarmer
...that's very interesting, and much more detailed a calculation than any I've seen put forth elsewhere.
One question, if you will permit me. Your first graph (above), there seems to be no difference at all in the two wheelsets, even accelerating from low speed.
I'm not questioning either your expertise (I don't know you), or your mathematics. But this seems to fly in the face real world experience, even of the staunchest "wheel weight doesn't matter" folks here. All of them have argued that it does, at least, matter in accelerating from a standing start. In fact, a couple of them took great offense at my suggestion we go back to steel as a wheel rim material. Am I reading your graph wrong, or is there some other explanation ? If I am going to be wrong about something, I'd at least like to learn from it. And I freely admit, I learned little about pendulums here.
Is 6 or 7 MPH the magic number where this weight difference no longer matters ? There seem to be no blue line values below that.
In the first graph, it's hard to see because of the scale. The second graph is just a zoomed in section of the first. I think that 250g per wheel just isn't enough to see much difference when considering the low relative mass of the wheels as compared to the whole system. Below is a zoomed in plot of distance vs time at around 20 seconds. The lighter wheels show a gain of about 1 meter - would definitely be worth something in a sprint event on a track. The second plot shows a more zoomed in part of the speed vs time with a bigger weight difference (1kg and 2kg).
