4 ms·

It should be possible to put limits on the lost energy of individual components, and in doing so, quantify the range of the problem. e.g.: For now, let's assum

It should be possible to put limits on the lost energy of individual components, and in doing so, quantify the range of the problem. e.g.: For now, let's assume that the wheel is a torsional spring, we're putting a force of 1000N (~100kg*g) at the rim, (roughly 300NM torque) and it deflects 1 degree. The energy that goes into the elastic deformation of a torsional spring is k(theta)^/2, t=k(theta), so energy = t(theta)/2. Plugging the numbers, you get 2.5 joules. Now, 1000N is a lot of force, and you're only likely to have that level of force with a heavy rider in a very low gear. (i.e., your tires have a coefficient of friction around 1, so that's implying 100kg on the back tire just to prevent wheelspin) But 2.5 joules starts to sound like it _might_ be measurable, and maybe look at the numbers a little more closely to see if they're reasonable. I'm only a fairly decent rider, but even then that's only about 1% of my 5 minute output, (if you assume 1 power stroke per second).

rawland 10y ago
World Class Levels (Duration vs. Watts/kg of Rider): 5s: 23 1min: 11 5min: 7.5 20min: 6.5 UCI Div. 3 pro (my [former] level): 5s: 20.28 (that's touching UCI Div 1/2 - sprinter type) 1min: 10.14 5min: 6.43 20min: 5.14 More details: https://www.cyclinganalytics.com/blog/2012/06/watts-kg-on-the-power-curve https://www.cyclinganalytics.com/blog/2012/06/watts-kg-on-th... Side note: Rumors were that the big LA had 20min+ values above 7.5, which is pure alien. The 5min test is hell, because one stresses _all_ energy systems in the human body to their maximum effort. So you ride in pain after something like 30 secs till the finish, which feels eternal. The 20min test is more easy compared to that, as it is very close to your general endurance. Thus, a top rider these days would rip his legs & mind out, when climbing besides the former LA.
- wiredfool 10y ago
  Well, my 5 minute number is how long it takes me to climb a steepish local hill, when I'm doing a few reps. So it's imprecise, and there's like one significant figure. 250-300 watts is my guess. And half as fast as cat3? Yeah, I could see that. My point still is, it's possible to calculate the upper limit on losses from wheel flex under power load, and I'd assert that they are small enough to not matter. And what's more, the effect of torsional spring type flex goes down (at a constant power output) as speed goes up.

rawland 10y ago

World Class Levels (Duration vs. Watts/kg of Rider): 5s: 23 1min: 11 5min: 7.5 20min: 6.5 UCI Div. 3 pro (my [former] level): 5s: 20.28 (that's touching UCI Div 1/2 - sprinter type) 1min: 10.14 5min: 6.43 20min: 5.14 More details: https://www.cyclinganalytics.com/blog/2012/06/watts-kg-on-the-power-curve https://www.cyclinganalytics.com/blog/2012/06/watts-kg-on-th... Side note: Rumors were that the big LA had 20min+ values above 7.5, which is pure alien. The 5min test is hell, because one stresses _all_ energy systems in the human body to their maximum effort. So you ride in pain after something like 30 secs till the finish, which feels eternal. The 20min test is more easy compared to that, as it is very close to your general endurance. Thus, a top rider these days would rip his legs & mind out, when climbing besides the former LA.

wiredfool 10y ago
Well, my 5 minute number is how long it takes me to climb a steepish local hill, when I'm doing a few reps. So it's imprecise, and there's like one significant figure. 250-300 watts is my guess. And half as fast as cat3? Yeah, I could see that. My point still is, it's possible to calculate the upper limit on losses from wheel flex under power load, and I'd assert that they are small enough to not matter. And what's more, the effect of torsional spring type flex goes down (at a constant power output) as speed goes up.