tag:blogger.com,1999:blog-36139180.post3716854937585779276..comments2024-08-24T07:59:12.309-04:00Comments on Sprinter della Casa: Equipment - Rotational InertiaAkihttp://www.blogger.com/profile/00430651087205849350noreply@blogger.comBlogger2125tag:blogger.com,1999:blog-36139180.post-63643472332403974232012-06-12T10:23:50.866-04:002012-06-12T10:23:50.866-04:00I realize the number of trials would be limited; i...I realize the number of trials would be limited; if I could see a trend then that would encourage me to do more tests/trials.<br /><br />1. More trials - yes.<br /><br />2. Friends do riding - yes, I thought about this. It would dilute the data for myself (since my pedal stroke, my power curve, etc, are mine). I was thinking that whoever would be patient/good enough to drive the "moto" would have to be a rider, and such a rider could then do a bunch of sprints while I rested.<br /><br />3. Blind randomized tests. I considered this too, but I'd need a third person. The front wheels I have are identical (one will have the lead tape), and I have two identical bottles (and one will have the same amount of lead tape in it, or just extra water). The weighted wheel and lighter bottle will be one set, the unweighted wheel and heavier bottle the other. If there's a third person putting the front wheel on and switching bottles then the rider and driver wouldn't know which is which.<br /><br />My challenge is that I want to have a significant weight difference at the rim, like 400-500g minimum. I don't want to have a 50g difference, it won't have a great effect on the numbers (because, as you pointed out, I won't have a lot of trials). The lead tape I bought is very light, like 100g worth. I'd either have to get another $80 worth of tape or find an alternate way of weighting the wheel.<br /><br />I was thinking of a spring weight setup I saw somewhere online. It's meant for giving the rider good inertial weight at speed but when you slow down the weights retract toward the hub. it's illegal for racing use but for the experiment it would have potential. Basically there are weights that slide up and down the spokes. If I had such a setup on a front radial laced wheel, no springs, and two sets of "weights" (one set would be light, one set very heavy), then the front wheel would look the same each sprint - one weight on a spoke near the hub, the other near the rim (one weight would be hollow). The third party person could swap all the weights. This keeps the weights on the wheel (truly measuring rotational inertia, since all the weight stays on the wheel), it avoids switching wheels, no bottle changes, can fit any size bike, etc. This would also allow much more weight, depending on the hub flange size and the diameter of the weight "bullets" that would fit on each spoke.Akihttps://www.blogger.com/profile/00430651087205849350noreply@blogger.comtag:blogger.com,1999:blog-36139180.post-35184782199258075982012-06-12T08:47:39.394-04:002012-06-12T08:47:39.394-04:00It's a good experiment, except that the number...It's a good experiment, except that the number of trials proposed is not enough to be statistically significant. Maybe enough to observe a numerical "trend" but not to prove it either way. Also experimental bias: you want to believe that the hypothesis is true and could subconsciously effect the outcome by "placebo effect" or "willing it to be true". So to be "valid" in the scientific sense you need: <br /><br />(1) More trials, to reach statistical significance <br /><br />(2) Your friends have to do the riding, not yourself (to remove subjective bias) <br /><br />(3) Blind, randomized trials, the rider cannot be allowed to know whether they are using a weighted or non-weighted wheel <br /><br />Maybe first do it your way, and then more scientifically if it seems worthwhile.DJnoreply@blogger.com