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revised How difficult would it be to maintain 17.5 Mph for an hour?
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answered How difficult would it be to maintain 17.5 Mph for an hour?
1h
revised Analysis of Stages high-speed data
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Aug
29
answered What is the difference between Time-Trial and Triathlon bikes?
Aug
26
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21
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Aug
10
revised How much faster will I be if I lose 10kg (from 100kg, all else equal)
added calculation of speed increase on climbs
Jul
31
comment How much speed can I buy
If money were no object, you could spend it on a streamlined vehicle like the Delft VeloX. It has CdA < .02 m^2 and special $400 tires (that are good for perhaps 20 km of use) with Crr < .002. On a flat road and zero wind, at 140 watts and a total mass of 105 kg you ought to be able to achieve ~ 80 km/h.
Jul
31
comment How much speed can I buy
We have long known what it takes to go faster: either increase the power you can make or reduce the power you must make. If your power output is fixed, you're looking at reducing the power needed to overcome drag. That means reducing rolling resistance, aerodynamic drag, and efficiency losses. Compared to typical tires/tubes the best can reduce the coeff of rolling resistance from perhaps .006 to perhaps .0025. Drivetrain efficiency can be improved from typical 95 or 96% up to maybe 97%. Aero drag on a standard bike can be reduced from perhaps .4 m^2 to under .3 m^2.
Jul
28
comment Are Osymetric chainring and power2max Classic power meter compatible?
That was just an example -- there are other times when absolute accuracy matters. It's just that training typically isn't one of the uses for a power meter that requires very high data fidelity; that's why people have been able to train effectively without one. There are, however, things that would be very difficult to do without a power meter, and these generally require accuracy. An example is VO2Max testing with a ramp protocol, since the ramps need to be of known and equal size.
Jul
28
comment Are Osymetric chainring and power2max Classic power meter compatible?
Absolute accuracy (rather than relative accuracy) can matter depending on what you're doing. For example, if you are trying to estimate aerodynamic or rolling resistance, you'll need absolute accuracy across the range of speeds you're likely to experience.
Jul
20
comment Descending without braking: where's the sweet spot?
@StephanMatthiesen In almost all cases what matters is CdA rather than the separate components Cd and A. In general, you measure the total drag in Newtons or lbf, then convert that to CdA, then if you're really interested you measure A and divide to get Cd.
Jul
18
comment Is there a standard equivalent for effort between distance and elevation?
@TomSterkenburg We discussed how to calculate drag resistance in this stackexchange question: bicycles.stackexchange.com/questions/9938/…
Jul
16
comment Why are so many technical aspects of cycling so subjective?
There is testing but mostly it's not widely known. For your particular example, see here and here.
Jul
10
comment Swain Power-HR relation
Exactly, though you'll want to exhaust your anaerobic capacity or else you'll overestimate VO2Max. That's why VO2Max tests are usually done with a ramped protocol, and the estimates are done off the final step before failure. In your example, you don't want to use the average of 97kJ for 5 minutes, instead you might want to use the max power over the last minute of a ramped protocol (or another similar protocol where you've exhausted the anaerobic component).
Jul
10
comment Swain Power-HR relation
Ah, okay. The issue is that even if you have HR, you don't have stroke volume which is what you need to get cardiac output. However, if you know metabolic efficiency (net or delta or work efficiency are better than gross efficiency, but sometimes all you have is gross efficiency) you can go from work to get L of O2 consumed, so if you have total mass you can estimate VO2Max. So you don't really need HR -- Swain was using that because he didn't have power, but you do. So do a VO2Max-level power effort and convert directly to estimate VO2Max.
Jul
10
comment Swain Power-HR relation
Can you clarify your question? The Swain model is used to estimate power when you know heart rate, VO2Max, and metabolic efficiency. You appear to have power and HR. Are you trying to go backwards to estimate VO2Max, or metabolic efficiency, or something else?