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Jan
26
comment How do I train to gain Tony Martin/Fabian Cancellara/Bradley Wiggins esq abilities to turn over a big gear 58t, 11t,?
This is an overly broad question and the answers would then also be overly broad and thus wouldn't particularly fit in the Q-and-A format. Can you narrow your question to something more specific?
Jan
23
comment Are 130 BCD chainsets stiffer than 110 BCD?
I'm slightly confused by your question. You mean for the same size chain rings, like 52-tooth or 39-tooth? Or do you mean a 34-tooth chain ring on a 110 BCD crank vs. a 39-tooth ring on a 130 BCD crank but with corresponding differences in the rear cogs so that the overall gear ratio is held constant? What is the comparison you're trying to make? (BTW, for the same power input and cadence at the crank, force on the chain ring is inversely proportional to the number of teeth on the chain ring, so a 34-tooth chain ring carries 39/34 = 1.15 ==> 15% more force than a 39-tooth ring.)
Dec
17
comment Why can't the gear ratio be something like 100:1? Is it practically possible?
fredrompelberg.com/upload/algemeen/Wereldrecord_fiets.JPG
Dec
17
comment Why can't the gear ratio be something like 100:1? Is it practically possible?
1899, at 63+ mph, by Charles "Mile-a-minute" Murphy. The current absolute speed record is held by Fred Rompelberg at 167 mph. He used a double reduction gear (70/13 connected to a 60/15 for a total gear ratio of 21.5) and his wheels were 18 inches in diameter.
Nov
19
comment How are the categories for climbs decided?
I used the official TdF website for the name of each climb, its category, length, and gradient. Given those data, it's simple to calculate the elevation contours.
Aug
21
comment Is vehicular cycling legal in France?
Nice answer. Could you add a reference to R414-2 and R414-4-IV? I believe the latter in particular is relevant to the question.
Jun
13
comment Is there a simple way to measure, record, and use wind resistance or tail winds?
Very nice. Two small correction: in part 2, air resistance varies with the square of air speed. Therefore, the power needed to overcome that air resistance approximately varies with the cube of speed (actually, (ground speed)*(air speed)^2 ). And, wind doesn't alway cancel out over the same route. Wind often has a pattern determined by geography and season, and wind speeds follow a Weibull distribution so, for example, you can end up with more extreme headwinds in the afternoon than tailwinds in the morning.
Jun
10
comment Is there a simple way to measure, record, and use wind resistance or tail winds?
Yes, the iBike (and other bicycle power meters) was discussed in this bicycles.stackexchange answer.
Jun
10
comment Is there a simple way to measure, record, and use wind resistance or tail winds?
Actually, we can measure all of those individual factors. However, measuring them all is either hard or expensive, and the OP's question was whether "there is a simple way" to do this. I was struggling with a way to write a simple response to a simple question but your short response is superior to the long (and growing) answer I was working on so I'm going to upvote yours and abort mine.
Jun
9
comment Is there a simple way to measure, record, and use wind resistance or tail winds?
There are, but they're of limited usefulness because you'd then need to "subtract" your ground speed from the indicated air speed to get the net speed of the wind. But since you're mostly interested in accounting for the wind speed in order to get a better sense of performance gains, there are other ways to measure that. I'll work on an answer.
Jun
8
comment Is there a simple way to measure, record, and use wind resistance or tail winds?
Is your question about measuring wind, or is it really about measuring performance improvements in the presence of wind that confounds the measurement? That is, there are anemometers that can measure and record wind but that's not particularly a bicycle-specific question.
Dec
24
comment How accurate are the power numbers from a Tacx Flow?
I'm not sure I understand your comment. The TACX documentation did not specify a particular value for calibration, so I just calibrated it so that it would be the same value (= zero) each time I used it. As I said, the Flow was consistent but inaccurate.
Dec
4
comment What bags will fit a Challenge Seiran SL?
Doesn't Challenge sell both a short rack and a Voyager rack that will fit the Seiran?
Nov
30
comment DIY computational fluid dynamics for aerodynamics?
Yeah, I guess I'm "that" guy. I think your question was a little open-ended but there's an interesting bicycle-related kernel in there. I'm thinking about how best to answer the kernel.
Nov
30
comment DIY computational fluid dynamics for aerodynamics?
Defraeye et al. (2010) did some work with CFD and wind tunnel measurements, and claimed to get reasonably good modeling. Getting quick CFD is the holy grail, of course -- but the problem is "quick."
Nov
29
comment DIY computational fluid dynamics for aerodynamics?
I don't know, I sorta like the reference to "the Chung Method."
Nov
15
comment Is the Power Pilot the only speedometer / computer that will work on a LeMond Revolution Trainer?
An alternative to buying a Power Pilot may be to mount a cheap speedometer using the small magnet attached to the "wheel", then use the information here to calculate power for speed, print that out on a sheet of paper, and tape it to the wall next to your trainer. If you can afford a slightly nicer ANT+ capable speed sensor plus ANT+ USB dongle, you can then use the trainerroad application or Golden Cheetah to display speed and power on a computer screen.
Nov
2
comment Terminology index - a list of bike part names and cycling concepts
@freiheit: It's an English word that is also a French word. That's like saying "Paris" is an English word that's commonly mistaken for a French word. In English, we pronounce "pannier" as "PAN-yer" and "Paris" as "PAIR-iss" but in French they are pronounced "Pan-YAY" and "Pa-REE."
Oct
31
comment Why choose a traditional frame over an aerodynamically streamlined frame?
Speed increased for the same power output. Power output decreased for the same speed. Power and speed were recorded electronically at one-second intervals. The electronic recording device was not influenced by the rider's beliefs, so claiming that the estimation of Crr and CdA was the result of a placebo effect is incorrect.
Oct
31
comment Why choose a traditional frame over an aerodynamically streamlined frame?
@meagar: Exactly. But the metrics are not speed and power. The metrics are CdA and Crr. We're using a power and speed recorder to record the data in order to calculate CdA and Crr, which are independent of speed and power. In fact, it's the variance in speed and power that make CdA and Crr estimable. We could have done the estimation with a powered electric bicycle, varying the throttle and speed and still estimated CdA and Crr. Even if the rider had a prior belief it's the relationship between power and speed that matters -- and that is what is recorded.