Originally Posted by
Yoshi
So what you're saying is that it only takes 7 watts to go from 36mph to 43mph when you're sprinting? Because if you believe that you're only saving 2 watts, then you also believe that it only takes 7 watts of power to sprint.
Obviously it takes a lot more wattage to go from 36 to 43mph in 7 seconds. Likewise, you are going to save a lot more than 2 watts by dropping 412g. Assuming a linear curve (which it almost definitely isn't), if it took you a 500 watt increase to accelerate from 36-43mph dropping 412g would mean you'd only need a 357 watt increase to go from 36-43mph.
Of course the relationship is far from linear so you wouldn't save 143 watts, but you'd definitely save far more than 2.
Personally, I think it takes close to 1500W to do this
Yeah, like DrWJ said, all I'm trying to measure is the effect of rotating mass on bicycle acceleration. What I found is that it takes
around 2W to accelerate my tube and tire from ~450rpm to ~550rpm. Then I said that this rotating mass is similar to the difference between a pair of Zipp 404s vs Velocity Deep-Vs.
The 1-second interval in the PT combined with the speed reading lag are far from ideal for this test, but the system does respond at this level. If I spin up really fast from a standstill, I get about 50W, so it's not like it's always going to get single-digits or anything.
I have not done an error analysis on this, but I feel I've made a decent argument that rotating weight in bicycle wheels has a very very small impact on performance. Compared to aerodynamics with deep section rims, rotating weight is irrelevant.