Velodrome turn score: Magilla 1, RBR 0
MagillaGorilla
This is an actual graph of what I assume is accurate data from Bob's 4km
pursuit ride on a velodrome. It clearly shows that a rider is losing
significant watts in turns (on the order of 30-100 watts) due to what
appears to be the severe negative effects of centrifugal force on the
rider's physiology - specifically, it's much harder for the circulatory
system to pump blood back to the heart under heavy, positive G forces
(this is why jet fighter pilots wear G-suits). And this results in
lower wattage output in the turns.
How do you people refute this data?
Surely you can't argue there would be severe wattage spikes evenly
spaced like this had Bob done a 4km TT on a flat, straight 4km course.
I mean not even a cyclist with Tourette's Syndrome would have a wattage
graph like that on a straight, flat course. So it's obviously caused by
the turns.
This is a new revelation that nobody else has mentioned except me.
Although all this proves is a cyclist outputs less watts in a velodrome
turn at maximum effort due to the severe negative physiological effects
caused by higher G's in a velodrome turn. (It doesn't really clarify
whether you will go slower in a velodrome turn at constant wattage,
which is what we had been arguing for the last 47 years). But it now
appears a rider cannot even keep constant wattage in a velodrome turn
even if he wanted unless it was well below max. But nobody really cares
about what happens at low to medium wattage outputs anyway.
This graph also appears to show you actually do go slower in a velodrome
turn at maximum effort, as the onset of increasing speed spikes are in
almost perfect synchronicity with the end of wattage lows (there appears
to be a small lag effect).
This is a huge victory for the gorilla's velodrome slower-in-a-turn
camp, as nobody really expected to see turns causing such a huge
negative effect on wattage output. It appears that the physics of a
turn itself might not even be relevant to determining speed in a
velodrome turn.
Bring it on Carl, Kyle, Dan - let's hear your analysis of this graph.
You guys are on the canvas and the ref is
counting...one...two...three....four....
Get up Rocky, get up!
Apollo "Magilla" Creed
Velodrome Turn Expert
San Diego Zoo
Ewoud Dronkert
> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>
> This is an actual graph of what I assume is accurate data from Bob's 4km
> pursuit ride on a velodrome. It clearly shows that a rider is losing
> significant watts in turns (on the order of 30-100 watts) due to what
> appears to be the severe negative effects of centrifugal force on the
> rider's physiology - specifically, it's much harder for the circulatory
> system to pump blood back to the heart under heavy, positive G forces
But don't you see that almost every wattage drop is accompanied by a
speed increase?
I don't think the main reason for the drop is because the heart has to
pump harder, just heavier legs.
--
E. Dronkert
joseph.sa...@gmail.com
Do you know how this data was obtained? I recall seeing someplace that
some systems (PowerTap? SRM?) were susceptible to fluctuation from G's.
Could be my imagination. Why does the speed not track with the watts?
Does someone have video of a kilo or pursuit? Why don't we just have a
look using the magic of slow-mo to measure how long they are on
different parts of the track?
Joseph
MagillaGorilla
> MagillaGorilla wrote:
>
>> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>>
>> This is an actual graph of what I assume is accurate data from Bob's
>> 4km pursuit ride on a velodrome. It clearly shows that a rider is
>> losing significant watts in turns (on the order of 30-100 watts) due
>> to what appears to be the severe negative effects of centrifugal force
>> on the rider's physiology - specifically, it's much harder for the
>> circulatory system to pump blood back to the heart under heavy,
>> positive G forces
>
>
> But don't you see that almost every wattage drop is accompanied by a
> speed increase?
I think you are reading the graph wrong. They are offset peaks. When
you lose 100 watts you go faster? You don't really believe that, do
you? What's happening is you lose those watts in the turn, and then you
gradually speed up in the straightaway. That's why each low point on
the wattage plot is followed by an incline on the speed plot.
There's also a lag effect in there which I don't feel like explaining
now because I'm eating dinner.
> I don't think the main reason for the drop is because the heart has to
> pump harder, just heavier legs.
>
Your entire body is subject to the increased G-forces equally, not just
your legs. The biggest effect is that your veinous blood pools in your
legs, causing backpressure, and cannot be pumped back up towards your
heart (your heart has to work much harder to overcome this). This is why
pilots wear G-suits. They mechanically pressurize the legs with air
bladders to help pump blood in the legs back up to the heart against the
G-forces.
Cyclists on velodromes don't wear G-suits.
Magilla
MagillaGorilla
I don't think this could be the case because if what you were saying is
true then as soon as one would hit the straightaways the watts would
IMMEDIATELY level off and stay constant (it would be a flat line on a
graph). We don't see any flat lines on the wattage graph.
Instead, we see the watts either are gradually increasing or gradually
decreasing. This means that gradual, cyclical wattage changes are also
occurring on the straightaways. This means the effect must be
physiological and not mechanically induced by G-forces since the
straightaways have constant G-forces of 1g and should have no such
effect on a power meter.
The reason why watts aren't constant on the straightaways is because the
body takes the entire straightaway to recoup for the G-load effect in
the turns and by the time it does this (high wattage spike), the next
turn arrives and cycle repeats itself.
If the wattage decreases were due to G-forces in a turn (and not the
cyclist), then as soon as the bike hit the straightaway the wattage line
would go flat for the entire straightaway. I don't see any such pattern
once. This means the effect has to be physiologically induced since it
is occurring also on the straights.
I want to add another negative physiological effect to a veldrome turn
while I'm at it: vertigo.
So now you have G-loads and vertigo. Take that.
Magilla
Carl Sundquist
"MagillaGorilla" <Magilla...@zoo.com> wrote in message
news:PIqdneMcFIc...@ptd.net...
> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>
> This is an actual graph of what I assume is accurate data from Bob's 4km
> pursuit ride on a velodrome. It clearly shows that a rider is losing
> significant watts in turns (on the order of 30-100 watts) due to what
> appears to be the severe negative effects of centrifugal force on the
> rider's physiology - specifically, it's much harder for the circulatory
> system to pump blood back to the heart under heavy, positive G forces
> (this is why jet fighter pilots wear G-suits). And this results in lower
> wattage output in the turns.
>
> How do you people refute this data?
>
>
> Bring it on Carl, Kyle, Dan - let's hear your analysis of this graph. You
> guys are on the canvas and the ref is
> counting...one...two...three....four....
>
> Get up Rocky, get up!
Rocky is rolling on the ground laughing at Apollonia. He'll get up when he
feels like it.
Watts drop in the turn because you're trying to maintain a steady speed, not
because of G force loads. Individual pursuits are insignificant in terms of
G forces. What you're saying is that his legs load up with blood due to "the
severe negative effects of centrifugal force on the rider's physiology"
approximately every 8 seconds, yet can unpool again enough to hit
consistently high wattage peaks, again, every 8 seconds, for a total of 30
cycles in four minutes? It's amazing there's enough blood left in his brain
to maintain consciousness during the ride.
At that's at the relatively slow average speed of 45 kph. How can team
pursuit riders do it, especially without piling into each other as the rider
in front of them bogs down? Consider that the world record for team pursuits
is an average speed greater than 60 kph. Moreso, how can the motorpace
riders manage to survive an hour of this "severe negative effects of
centrifugal force on the rider's physiology" hell and stay close to the
wheel of a mechanically driven derny when their legs are bloated?
Some people wonder if you're AVA. No way would Albright have gone off on
ponderous, speculative, backpedaling tangents like this.
ilan
designed, that is, there is a slight uphill going into the turn and
slight downhill coming out of the turn. Apparently, this is very
noticeable if you ride on the track in the "wrong" direction, which
I've never done.. It is very noticeable as you move up the track, as I
have experienced.
-ilan
Robert Chung
MagillaGorilla
> "MagillaGorilla" <Magilla...@zoo.com> wrote in message
> news:PIqdneMcFIc...@ptd.net...
>
>>http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>>
>>This is an actual graph of what I assume is accurate data from Bob's 4km
>>pursuit ride on a velodrome. It clearly shows that a rider is losing
>>significant watts in turns (on the order of 30-100 watts) due to what
>>appears to be the severe negative effects of centrifugal force on the
>>rider's physiology - specifically, it's much harder for the circulatory
>>system to pump blood back to the heart under heavy, positive G forces
>>(this is why jet fighter pilots wear G-suits). And this results in lower
>>wattage output in the turns.
>>
>>How do you people refute this data?
>>
>
> <<snip>>
>
>>Bring it on Carl, Kyle, Dan - let's hear your analysis of this graph. You
>>guys are on the canvas and the ref is
>>counting...one...two...three....four....
>>
>>Get up Rocky, get up!
>
>
> Rocky is rolling on the ground laughing at Apollonia. He'll get up when he
> feels like it.
>
> Watts drop in the turn because you're trying to maintain a steady speed, not
> because of G force loads. Individual pursuits are insignificant in terms of
> G forces.
So you let off the pedals in a turn? Why not go as fast as you can? No
you don't. In fact, you'd see the same oscillations and spikes in
speed/wattage in an hour record attempt as a pursuiter (both are
basically maximum aerobic efforts). There's no way I believe riders are
intentionally slowing up in the turns in an hour record or pursuit just
to maintain some kind of smooth speed.
What you're saying is that his legs load up with blood due to "the
> severe negative effects of centrifugal force on the rider's physiology"
> approximately every 8 seconds, yet can unpool again enough to hit
> consistently high wattage peaks, again, every 8 seconds, for a total of 30
> cycles in four minutes?
I'm not saying this - the data is saying this.
It's amazing there's enough blood left in his brain
> to maintain consciousness during the ride.
The body recovers in the straightaways and the G-loads in the turns
isn't severe enough (or long enough) to reach blackout forces (> 9 g's).
But it's apparently enough to cause significant drops in wattage due
to circulatory stresses.
> At that's at the relatively slow average speed of 45 kph. How can team
> pursuit riders do it, especially without piling into each other as the rider
> in front of them bogs down?
It's a gradual effect that the riders behind also feel, albeit delayed.
Loss of wattage does not immediately transfer into loss of speed.
It's gradual. That's why the graph shows relatively gradual
accelerations and decelerations. The spikes are exaggerated because of
disproportional units of scale on the Y-axis.
Consider that the world record for team pursuits
> is an average speed greater than 60 kph. Moreso, how can the motorpace
> riders manage to survive an hour of this "severe negative effects of
> centrifugal force on the rider's physiology" hell and stay close to the
> wheel of a mechanically driven derny when their legs are bloated?
The G-forces aren't that great Carl. I'm only using the word "severe" in
a relative sense to describe its apparent "severe" affect on wattage
output according to the data (30-100 watts with an average loss of
wattage of around 80). The G-forces are great enough to mess up the
body's physiological ability to generate watts. I don't see why an
elite cyclist would be much better off than Bob.
In fact, an elite pursuiter or hour record guy might even see greater
loss of watts in turns because he is taking more speed into the turns
and G's is a function of speed and weight (more speed, higher G's).
Ferrari claims physiological G-force effects in a velodrome turn when
setting an hour record is a huge factor.
----------
http://www.53x12.com/do/show?page=article&id=31
Finally, at these speeds the one-hour record, with the 442 curves Tony
had to negotiate, became a kind of a ride through a ‘centrifuge’.
Carrying 15 kg in weight and 13 cm in height more than his rival,
Indurain clearly suffered more from the centrifugal force in the curves.
This would have been due to the increased rolling friction (which is
directly proportional to weight, and through the curves at these speeds
the combined weight of bike plus rider virtually doubles), as well as to
a more difficult vein blood return from the legs to the heart due to
Indurain’s greater height.
-----------
Me and Ferrari think the same on this issue. Bob's data merely
quantifies it.
Magilla
MagillaGorilla
That's hot.
Paris
Phil Holman
"MagillaGorilla" <Magilla...@zoo.com> wrote in message
news:PIqdneMcFIc...@ptd.net...
> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
Bob backed off in the turn for some reason!!
http://storeandserve.com/download/695244/Power_Output_and_Speed_for_a_Kilo.xls.html
This guy didn't. Click on the link, then the download button and then
the link at the bottom of the page. It's an excel file/plot.
Phil H
Carl Sundquist
"ilan" <ila...@yahoo.com> wrote in message
news:1168993984.7...@m58g2000cwm.googlegroups.com...
>I believe that this phenomenon could be explained by the way tracks are
> designed, that is, there is a slight uphill going into the turn and
> slight downhill coming out of the turn. Apparently, this is very
> noticeable if you ride on the track in the "wrong" direction, which
> I've never done.. It is very noticeable as you move up the track, as I
> have experienced.
>
It depends on the design of the velodrome and where you ride on the track.
Ideally, the pole line (the black line slightly above the cote d'azur, the
official bottom of the track) should be level all the way around the track.
Nonetheless, you will find the top riders actually ride the track
elliptically, riding part way up into the sprinter's lane on the straights.
Bob Schwartz
{Quack, quack, quack}
Ladies and gentlemen of this supposed newsgroup, the monkey
would certainly want you to believe that people slow down in
velodrome corners. And he makes a good case. Hell, I almost
felt pity myself! But, ladies and gentlemen of this supposed
newsgroup, I have one final thing I want you to consider.
Ladies and gentlemen, this is Chewbacca. Chewbacca is a Wookiee
from the planet Kashyyyk. But Chewbacca rides on the planet
Endor. Now think about it; that does not make sense!
Why would a Wookiee, an eight-foot tall Wookiee, want to ride
on Endor, on a velodrome with a bunch of two-foot tall Ewoks?
That does not make sense! How would he ride Madisons with a
two foot tall partner. But more important, you have to ask
yourself: What does this have to do with this case? Nothing.
Ladies and gentlemen, it has nothing to do with this case!
It does not make sense! Look at me. I'm a usenet troller defending
BS physics, and I'm talkin' about Chewbacca! Does that make sense?
Ladies and gentlemen, I am not making any sense! None of this
makes sense! And so you have to remember, when you're in that
jury room deliberatin' and conjugatin' the Emancipation
Proclamation, [approaches and softens] does it make sense? No!
Ladies and gentlemen of this supposed newsgroup, it does not make
sense! If Chewbacca rides on Endor, he goes faster in velodrome
turns! The defense rests.
Bob Schwartz
b...@mambo.ucolick.org
> Carl Sundquist wrote:
>
> > Watts drop in the turn because you're trying to maintain a steady speed, not
> > because of G force loads. Individual pursuits are insignificant in terms of
> > G forces.
>
> So you let off the pedals in a turn? Why not go as fast as you can? No
> you don't. In fact, you'd see the same oscillations and spikes in
> speed/wattage in an hour record attempt as a pursuiter (both are
> basically maximum aerobic efforts). There's no way I believe riders are
> intentionally slowing up in the turns in an hour record or pursuit just
> to maintain some kind of smooth speed.
Riders can't accelerate bicycles very quickly. There is a limit
to the rate at which you can change the power you're applying
to the pedals, and a limit to how fast you can speed up your
cadence. When you're pedaling at a certain rate and suddenly
some of the load force is taken off, it takes a moment to catch up
and get your cadence up to a higher rate. During that time
your power drops a bit because you haven't fully caught up to
the pedals. This is presumably what people are talking
about when they talk about "floating" the turns in a pursuit.
You can google this group for several examples. For example,
your previous incarnation of this troll, five years back:
<http://groups.google.com/group/rec.bicycles.racing/msg/2f2e0ec7e70ec514>
and my worked-out example in the same thread of why the float
happens, showing that the energy contribution from the lower
center of mass dominates over the increased rolling resistance
and air resistance:
<http://groups.google.com/group/rec.bicycles.racing/msg/b35a20c8ba293bfd>
I said "presumably" about the float above because I've never
actually ridden a pursuit. However, the effect is also fairly clear
riding a fixed-gear on the road when you make a sharp transition
from riding on the flat to downhill. It happens on a non-fixed gear
bike too, but it's more obvious on a fixed gear because you can
feel the pedal pressure (sort of the bike telling you, "More steam,
Scotty!")
By the way, you still talk about physics like a twelve year old
boy talking about sex.
Your Monkey Daddy,
Ben
MagillaGorilla
Oh fuck, I was afraid of that. I actually thought to myself 'was Bob
backing off in the turns because he's not a track specialist?' This
would serve to cause the same effect.
I'm going to have to agree with you pH on this even though it hurts me
because I had suspicions those wattage drops were too great. But was
100% of that due to Bob's inexprience on a track? I dunno about that.
I initially assumed he wasn't backing off in the turns because when
someone purports to me they were doing a 4km individual pursuit effort
on a velodrome, I'm thinking it's a maximum effort from start to finish.
You don't back off in a 4km pursuit. There's no reason to. A 4km
pursuit is basically a maximum aerobic effort from start to finish.
But I agree with you that those huge power losses on Bob's graph are
suspicious.
The question is if someone like Sarah Ulmer did it, would it look
similar to Bob's, smoother, or perfectly smooth? I think if Sarah Ulmer
did it the peaks and troughs would be lower in amplitude but they would
still be there in cycles.
Conclusion: we need a professional pursuiter to run this test to rule
out inexperienced track riders. This isn't a slight against Bob - I
assume most pro road riders would even back off in a velodrome turn
(probaby unconsciously). It probably takes years to get good.
The Excel graph I downloaded was for a kilo event and the y-axis on the
power output isn't detailed enough for me to do an accurate comparison
with Bob's. I still think I see fluctiations like in Bob's graph
though, but they are somewhat masked and attenuated by 2 things
respectively: (1) the y-axis scale is too small and (2) the kilo event
lends itself to more of an anerobic effort than an aerobic effort. This
means that oxygenation is not going to be as severely affected by
G-loads in a turn.
I'd prefer to see a 4km pursuiter do this or better yet, and hour record
guy.
I also see speed fluctations but cannot tell if you go faster in a turn
or straightaway.
But after seeing it, it appears that wattage fluctuations on a velodrome
shouldn't be as much as what Bob had. The question is how much less
would they be if a top-level pursuiter did this test?
Magilla
Carl Sundquist
>>
>> Rocky is rolling on the ground laughing at Apollonia. He'll get up when
>> he feels like it.
>>
>> Watts drop in the turn because you're trying to maintain a steady speed,
>> not because of G force loads. Individual pursuits are insignificant in
>> terms of G forces.
>
> So you let off the pedals in a turn? Why not go as fast as you can? No
> you don't. In fact, you'd see the same oscillations and spikes in
> speed/wattage in an hour record attempt as a pursuiter (both are basically
> maximum aerobic efforts). There's no way I believe riders are
> intentionally slowing up in the turns in an hour record or pursuit just to
> maintain some kind of smooth speed.
Show me where anyone (besides you) has said anything about slowing in turns.
Does the data show that? What is a "maximum aerobic effort"?
>
>
> What you're saying is that his legs load up with blood due to "the
>> severe negative effects of centrifugal force on the rider's physiology"
>> approximately every 8 seconds, yet can unpool again enough to hit
>> consistently high wattage peaks, again, every 8 seconds, for a total of
>> 30 cycles in four minutes?
>
> I'm not saying this - the data is saying this.
The data doesn't say that, your interpretation of the data says that.
>
>
> It's amazing there's enough blood left in his brain
>> to maintain consciousness during the ride.
>
> The body recovers in the straightaways and the G-loads in the turns isn't
> severe enough (or long enough) to reach blackout forces (> 9 g's). But
> it's apparently enough to cause significant drops in wattage due to
> circulatory stresses.
>
"Apparently"? That's good enough for you?
>
>> At that's at the relatively slow average speed of 45 kph. How can team
>> pursuit riders do it, especially without piling into each other as the
>> rider in front of them bogs down?
>
> It's a gradual effect that the riders behind also feel, albeit delayed.
> Loss of wattage does not immediately transfer into loss of speed. It's
> gradual. That's why the graph shows relatively gradual accelerations and
> decelerations. The spikes are exaggerated because of disproportional
> units of scale on the Y-axis.
If it is delayed, then explain why the riders don't overlap wheels as they
successively go through the turns and catch up to the rider in front of
them.
>
>
> Consider that the world record for team pursuits
>> is an average speed greater than 60 kph. Moreso, how can the motorpace
>> riders manage to survive an hour of this "severe negative effects of
>> centrifugal force on the rider's physiology" hell and stay close to the
>> wheel of a mechanically driven derny when their legs are bloated?
>
> The G-forces aren't that great Carl. I'm only using the word "severe" in a
> relative sense to describe its apparent "severe" affect on wattage output
> according to the data (30-100 watts with an average loss of wattage of
> around 80). The G-forces are great enough to mess up the body's
> physiological ability to generate watts. I don't see why an elite
> cyclist would be much better off than Bob.
There's that "apparent" word again. Explain how a motorpace rider can stay
close behind the wheel of a mechanically driven derny.
>
> In fact, an elite pursuiter or hour record guy might even see greater loss
> of watts in turns because he is taking more speed into the turns and G's
> is a function of speed and weight (more speed, higher G's).
>
> Ferrari claims physiological G-force effects in a velodrome turn when
> setting an hour record is a huge factor.
>
> ----------
>
> http://www.53x12.com/do/show?page=article&id=31
>
> Finally, at these speeds the one-hour record, with the 442 curves Tony had
> to negotiate, became a kind of a ride through a ‘centrifuge’. Carrying 15
> kg in weight and 13 cm in height more than his rival, Indurain clearly
> suffered more from the centrifugal force in the curves. This would have
> been due to the increased rolling friction (which is directly proportional
> to weight, and through the curves at these speeds the combined weight of
> bike plus rider virtually doubles), as well as to a more difficult vein
> blood return from the legs to the heart due to Indurain’s greater height.
> -----------
>
> Me and Ferrari think the same on this issue. Bob's data merely quantifies
> it.
>
No, you merely repeated Ferrari's words without any scientific basis to back
them up. Where's Ferrari's data on wattage loss due to more difficult vein
blood return? If it was significant, why not wear compression hose? If it's
significant, why not do record attempts at the Krylatskoye velodrome in
Moscow where it is an indoor 333m track and the radius of the turns is 32
meters.
http://moscowtrackcup.worlds2005.com/krylatskoye.php?lang=eng
This would also mean 25% fewer turns that you claim slow down riders. The
only riders I'm aware of to do hour record stuff there are Ekimov in the
80's and Sosenka. Why, with all their financial and scientific resources,
didn't Boardman, Rominger, and Indurain make their attempts there? If it was
bad for Indurain, it was bad for Rominger too, just not as much. Most of
what Ferrari is talking about is weight on the arms and shoulders.
BTW, Ferrari states, "It is also important to note that the rider’s track
speed is anything but constant, presenting continued accelerations and
decelerations corresponding to curves and straight-aways." Do you think the
same as Ferrari here, too?
Ryan Cousineau
MagillaGorilla <Magilla...@zoo.com> wrote:
> Ewoud Dronkert wrote:
>
> > MagillaGorilla wrote:
> >
> >> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
> >>
> >> This is an actual graph of what I assume is accurate data from Bob's
> >> 4km pursuit ride on a velodrome. It clearly shows that a rider is
> >> losing significant watts in turns (on the order of 30-100 watts) due
> >> to what appears to be the severe negative effects of centrifugal force
> >> on the rider's physiology - specifically, it's much harder for the
> >> circulatory system to pump blood back to the heart under heavy,
> >> positive G forces
> >
> >
> > But don't you see that almost every wattage drop is accompanied by a
> > speed increase?
>
>
> I think you are reading the graph wrong. They are offset peaks. When
> you lose 100 watts you go faster? You don't really believe that, do
> you?
Clearly the effects of having the mass of the rider take a shorter path
than the actual track distance are being demonstrated here.
Good work!
--
Ryan Cousineau rcou...@sfu.ca http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
ilan
stay on the pole line as you start the turn, if you keep the same
speed, since that entails a change in velocity. By the way, I always
thought this was one of the reasons why you use smaller gears on the
track, e.g., even top pursuitists use much bigger gears in road
prologues of comparable distance.
-ilan
Phil Holman
> Yes, but even if the pole line is flat, you still have to accelerate
> to
> stay on the pole line as you start the turn, if you keep the same
> speed, since that entails a change in velocity. By the way, I always
> thought this was one of the reasons why you use smaller gears on the
> track, e.g., even top pursuitists use much bigger gears in road
> prologues of comparable distance.
>
> -ilan
The difference is, the pursuiter has a single gear with a compromise
between start acceleration and maintainable top end speed. I'm sure the
pursuiter would like to select a bigger gear when up to speed but the
rules don't allow. I remember seeing a device with two drive trains that
would effectively change gear after the start acceleration but this is
not legal.
Phil H
sl
ilan <ila...@yahoo.com> wrote:
>I believe that this phenomenon could be explained by the way tracks are
>designed, that is, there is a slight uphill going into the turn and
>slight downhill coming out of the turn. Apparently, this is very
>noticeable if you ride on the track in the "wrong" direction, which
>I've never done.. It is very noticeable as you move up the track, as I
>have experienced.
>>
>> This is a new revelation that nobody else has mentioned except me.
>>
>> Although all this proves is a cyclist outputs less watts in a velodrome
>> turn at maximum effort due to the severe negative physiological effects
>> caused by higher G's in a velodrome turn. (It doesn't really clarify
>> whether you will go slower in a velodrome turn at constant wattage,
Have you actually done any riding on a track?
I have a large number of files demonstrating the same phenomana.
Any higher G forces are certainly not very noticible while you are
actually going though the turn. Especially at less than 50kph. Certainly
less noticable than (for example) riding around in a small plane. At
least for me... YMMV.
Assuming that the rider was keeping close to the sprinters line (black
line) there is no change in elevation around the turn. But there will be
an "apparent" speed change and a real change due to the riders center
of mass lowering.
As you enter the turn and lean into it, the velocity of the rider (as
measured at his center of mass) will not change, but the radius of the
turn that the rider takes will be less than the outer edge of the
wheels, which is where the velocity measurement takes place. Effectively
the bike wheels traverse a larger circle and therefore measure a higher
speed.
Second as the center of mass lowers there is a increase of speed. Which
is reversed as you exit the turn.
The change in speed at the wheels in turn makes it difficult to maintain
a constant power output. Your power output is explicitly tied to cadence
and wheel speed (fixed gear rememeber..) As your wheel speed goes up,
your cadence goes up. And your legs react with changes in power output.
Which in turn reduces the actual speed as you come out of the curve...
There is an excellent analysis at www.analyticcycling.com, see the
"velodrome" model.
Donald Munro
> Watts drop in the turn because you're trying to maintain a steady speed, not
> because of G force loads. Individual pursuits are insignificant in terms of
> G forces. What you're saying is that his legs load up with blood due to "the
> severe negative effects of centrifugal force on the rider's physiology"
> approximately every 8 seconds, yet can unpool again enough to hit
> consistently high wattage peaks, again, every 8 seconds, for a total of 30
> cycles in four minutes? It's amazing there's enough blood left in his brain
> to maintain consciousness during the ride.
You mean track riders actually have brains ?
Michael Press
Calculate the g-force on a track rider in a turn.
--
Michael Press
MagillaGorilla
I would be more than happy to. But before I do any calculations, I need
to figure out everything going on in a turn. I don't want to get bogged
down with superfluous calculations that only describe 20% of a turn and
then try to pass that off as some kind of master equation.
And even then it's going to be arguably irrelevant because you would be
calculating the speed for a MACHINE going around a velodrome turn. To
calculate the effects of a HUMAN CYCLIST, you would have to deduct the
negative physiological effects of G-forces (as well as vertigo) on
wattage output. This data can only be obtained empirically through an
SRM on a velodrome as you'd probably need a supercomputer to calculate
what G-forces do to the physiology of a person if you actually wanted to
calculate it beforehand.
Right now, we don't even know what the rate-limiting factor is. If you
were to believe Bob's graph (i.e. that he was not slowing down
intentionally or unintentionally in every turn), it shows a rider loses
on average about 75 watts on a turn due to G-forces. That's a huge number.
But I'd have to see that kind of wattage drop in a world class pursuit
rider before I believed it was due totally to G-forces and not Bob's
(relative) inexperience on a track, in which he might be backing off on
a turn unconsciously.
I'd like to see the SRM data from Sarah Ulmer (world record holder in
3km pursuit). If she had no loss of power in a turn, then we know Bob's
was due to inexperience.
My guess is that Sarah Ulmer will show similar cyclical spikes to Bob's
data, but much less in amplitude. How much less, I don't know.
I would accept a world record holder's data as data that has minimal
artifacts due to inexperience.
Magilla
Dan Connelly
> Magilla wrote:
>> There's also a lag effect in there which I don't feel like explaining
>> now because I'm eating dinner.
To fair approximation, M v d v / d t = p - K v^3, for K which depends on
aerodynamics, where p is power, v is velocity, and M is system mass.
Since d v / dt, which is acceleration, is not zero, If acceleration
were very small, then to decent approximation, v = (p / K)^(1/3) -- no
lag. But if acceleration is significant, power goes into and comes out
of kinetic energy changes ( M v dv = d(M v^2 / 2) ) in addition to to
supporting wind resistance.
> Calculate the g-force on a track rider in a turn.
I already did in the countersteering thread:
Consider a 250 meter track, with 150 meters in corners, and 100 meters
in straights. If the corners are semicircular, they have a radius of R
= (150 meters / 2 pi). If the bike center-of-mass (COM) is going v = 60
km/hr = 16.7 m/sec, it is experiencing a centrifugal acceleration
relative to gravity of (v2/R g) = 1.19 (I'll define this as alpha).
Then the total acceleration ("g-forces") is g sqrt(1 + alpha^2) = 1.55 g.
If the speed is 45 kph, then this becomes alpha = 0.67, yielding instead
1.20 g.
MagillaGorilla
> In article <1168993984.7...@m58g2000cwm.googlegroups.com>,
> ilan <ila...@yahoo.com> wrote:
>
> There is an excellent analysis at www.analyticcycling.com, see the
> "velodrome" model.
>
http://www.analyticcycling.com/genmodel/LeanAnalysis.html
I read this page. Fine. Basically he says there's a 1.5 second savings
per 1 km. By the way, such a "speed increase" would hardly be
observable on a speedometer unless you looked at the tenths. You people
are talking about a speed increase in a turn like you have a fucking jet
rocket that kicks on when you enter a turn.
So the lean factor on a velodrome for a 4km pursuit saves around 6
seconds over that same course had it been straight. Here's the glaring
problem with his analysis, which is far too simplistic despite you
people being mesmerized by a lot of algebra.
This is what he doesn't deduct from that 6 second gain in a 4km ride on
a velodrome:
1. The negative effects of increased G-forces in turns on a rider's
physiological ability to generate watts.
2. The negative effects of vertigo in a turn on a rider's physiological
ability to generate watts.
3. Centrifigal force's effect on added friction due to increasing the
weight of a rider and bike in a turn and how this affects any
accleration in a turn (it will slow you down, since the rider's weight
is increasing by a factor of around 2).
4. The act of leaning up on a bike when exiting a turn takes more work
than leaning down and is less efficient than leaning down because of
gravity. Therefore they do not cancel out. I agree the part in between
the initial lean and rise is gravy. But there is slightly less gravy.
5. Increased aerodynamic drag in a turn (which includes the assymtrical
disruption of laminar airflow in a turn vs. a straightaway)
-------------------------------------
None of these factors are taken into account on that website! You would
need to get the aerodynamic data empirically from a wind tunnel as well
as the wattage loss empirically from an SRM by a world class rider (to
rule out artifacts caused by inexperience in riding velodrome turns).
So the question is - how much of that 6 second gain in a 4km pursuit is
going to be lost to the above factors? That 6-second gain is nothing
but a pipedream analysis and is not a real world calculation by any
stretch. It's some kind of partial physics analysis that only describes
a small part of what's actually occurring in a turn, and what's more,
would only apply to a non-human engine that would not be affected by
centrifugal forces.
Also, I'm not quite sure on this, but I think he needs to be factoring
in equations with weight and not only mass. Sure the center of mass
travels less distance, but that center of mass in a turn now weighs
twice as much as it does on a straightaway. A 75kg rider sustaining
2g's in a velodrome turn weighs 150kg in a turn. So even if you shave
some distance off it's center of mass travel, you are doubling the
bike/rider weight over that shorter distance. This increase in weight
will hurt you in any acceleration gains due to lean. He talks about the
distance gain from lean as if doubling the weight of a rider doesn't
matter. It does.
The only good news is this weight gain is not physiological, but it is
substantial.
Magilla
Michael Press
MagillaGorilla <Magilla...@zoo.com> wrote:
Just do it. Freshman physics. What is the g-load?
>
> And even then it's going to be arguably irrelevant because you would be
> calculating the speed for a MACHINE going around a velodrome turn. To
> calculate the effects of a HUMAN CYCLIST, you would have to deduct the
> negative physiological effects of G-forces (as well as vertigo) on
> wattage output. This data can only be obtained empirically through an
> SRM on a velodrome as you'd probably need a supercomputer to calculate
> what G-forces do to the physiology of a person if you actually wanted to
> calculate it beforehand.
I expect there are sides on the web that will tell you about this.
>
> Right now, we don't even know what the rate-limiting factor is. If you
> were to believe Bob's graph (i.e. that he was not slowing down
> intentionally or unintentionally in every turn), it shows a rider loses
> on average about 75 watts on a turn due to G-forces. That's a huge number.
`Lose' is not supported by that data.
> But I'd have to see that kind of wattage drop in a world class pursuit
> rider before I believed it was due totally to G-forces and not Bob's
> (relative) inexperience on a track, in which he might be backing off on
> a turn unconsciously.
>
> I'd like to see the SRM data from Sarah Ulmer (world record holder in
> 3km pursuit). If she had no loss of power in a turn, then we know Bob's
> was due to inexperience.
>
> My guess is that Sarah Ulmer will show similar cyclical spikes to Bob's
> data, but much less in amplitude. How much less, I don't know.
>
> I would accept a world record holder's data as data that has minimal
> artifacts due to inexperience.
Show us the math.
--
Michael Press
Bob Schwartz
> You mean track riders actually have brains ?
Not if the ability to maintain a constant effort is an
indicator.
Bob Schwartz
Michael Press
<Xgtrh.50127$wc5....@newssvr25.news.prodigy.net>,
Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>
wrote:
> Michael Press wrote:
> > Magilla wrote:
> >> There's also a lag effect in there which I don't feel like explaining
> >> now because I'm eating dinner.
>
> To fair approximation, M v d v / d t = p - K v^3, for K which depends on
> aerodynamics, where p is power, v is velocity, and M is system mass.
> Since d v / dt, which is acceleration, is not zero, If acceleration
> were very small, then to decent approximation, v = (p / K)^(1/3) -- no
> lag. But if acceleration is significant, power goes into and comes out
> of kinetic energy changes ( M v dv = d(M v^2 / 2) ) in addition to to
> supporting wind resistance.
>
> > Calculate the g-force on a track rider in a turn.
>
>
> I already did in the countersteering thread:
I was asking someone else.
> Consider a 250 meter track, with 150 meters in corners, and 100 meters
> in straights. If the corners are semicircular, they have a radius of R
> = (150 meters / 2 pi). If the bike center-of-mass (COM) is going v = 60
> km/hr = 16.7 m/sec, it is experiencing a centrifugal acceleration
> relative to gravity of (v2/R g) = 1.19 (I'll define this as alpha).
> Then the total acceleration ("g-forces") is g sqrt(1 + alpha^2) = 1.55 g.
>
> If the speed is 45 kph, then this becomes alpha = 0.67, yielding instead
> 1.20 g.
Consider a bicycle on a banked turn. We resolve the
forces along the perpendicular to the track and along
an axis transverse to the bicycle.
speed: v
radius of curvature: R
angle of track: b
centripetal acceleration = v^2 / R.
gravitational acceleration = g.
acceleration transverse to the bicycle:
a_t = (v^2/R * cos b - g * sin b) * m
acceleration perpendicular to the track:
a_p = (v^2/R * sin b + g * cos b) * m
Let us take a_t = 0, representing the situation where
the the gravitational force tending to tip over the
bicycle is balanced by the centripetal force.
Multiplying the first equation by sin b, the second by
cos b, then subtracting we get a_p * cos b = g * m so
the g-load is
g / cos b.
and v^2 = R * g * tan b.
Otherwise the g-load is g * sqrt(v^4/(g * R)^2 + 1),
as you say.
R = 25 m.
The balancing act at 12 m/sec gives tan b ~ 144 / 250,
or b ~ 30 deg and a g-load of 1.15.
The balancing act at 16 m/sec gives tan b ~ 256 / 250,
or b ~ 45 deg and a g-load of 1.41.
Here R is fixed, but it actually varies in practice.
Calculating the g-load with the formula g / cos b is sufficient.
--
Michael Press
Mark & Steven Bornfeld
I haven't been following this (ahem) interesting discussion. I think
any physicist could answer this in a moment. My feeling is you are
almost certainly right that application of centripetal force would not
affect power output of the physiology. However, I suspect it could
cause loss of power as measured because of heat dissipation that would
not be measured. Why would physiologic output be diminished--greater
load returning blood from the lower extremeties to the heart? Silly on
the face of it.
Steve
--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001
Mark & Steven Bornfeld
>
>
> I haven't been following this (ahem) interesting discussion. I
> think any physicist could answer this in a moment. My feeling is you
> are almost certainly right that application of centripetal force would
> not affect power output of the physiology. However, I suspect it could
> cause loss of power as measured because of heat dissipation that would
> not be measured.
I mean--greater heat loss in the turns, caused by overcoming angular
momentum.
S
Dan Connelly
> sl wrote:
>
>> In article <1168993984.7...@m58g2000cwm.googlegroups.com>,
>> ilan <ila...@yahoo.com> wrote:
>
>>
>> There is an excellent analysis at www.analyticcycling.com, see the
>> "velodrome" model.
>>
>
> http://www.analyticcycling.com/genmodel/LeanAnalysis.html
>
> I read this page. Fine. Basically he says there's a 1.5 second savings
> per 1 km. By the way, such a "speed increase" would hardly be
> observable on a speedometer unless you looked at the tenths. You people
> are talking about a speed increase in a turn like you have a fucking jet
> rocket that kicks on when you enter a turn.
My much, much simpler estimate, posted here, was a 4.8% speed advantage
while in the corners @ 60 kph, with the corners corresponding to 3/5 of
the total distance, yielding a net 2.9% speed advantage, which is 1.7
seconds per kilometer.
Dan
Dan Connelly
(slightly paraphrased)
> Consider a bicycle on a banked turn. We resolve the
> forces along the perpendicular to the track and along
> an axis transverse to the bicycle.
> speed: v
> radius of curvature: R
> angle of track: b
> centripetal acceleration = v^2 / R.
> gravitational acceleration = g.
>
> sin b * acceleration transverse to the bicycle = 0
> 0 = (v^2/R * cos*sin b - g * sin^2 b) * m
> cos b * acceleration perpendicular to the track:
> a_p*cos = (v^2/R * sin*cos b + g * cos^2 b) * m
>
> subtracting we get a_p * cos b = g * m so
> the g-load is
> g / cos b.
> and v^2 = R * g * tan b.
> Otherwise the g-load is g * sqrt(v^4/(g * R)^2 + 1),
> as you say.
>
> R = 25 m.
> The balancing act at 12 m/sec gives tan b ~ 144 / 250,
> or b ~ 30 deg and a g-load of 1.15.
> The balancing act at 16 m/sec gives tan b ~ 256 / 250,
> or b ~ 45 deg and a g-load of 1.41.
>
> Here R is fixed, but it actually varies in practice.
> Calculating the g-load with the formula g / cos b is sufficient.
This is an excellent analysis, but the force perpendicular to the track
is not relevant. Consider the trivial case of a cyclist doing a
trackstand on a banked track. The bike is upright -- perpendicular to
the earth. The angle of the track doesn't matter: he's experiencing 1 g
of force, not 1 g / cos b. The force experienced by the cyclist is the
total accelerating force, which is what I calculated. The banking angle
affects the traction force on the tires, but can't affect the forces
within the cyclist's body.
Dan
Andy Coggan
MagillaGorilla wrote:
> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>
> This is an actual graph of what I assume is accurate data from Bob's 4km
> pursuit ride on a velodrome. It clearly shows that a rider is losing
> significant watts in turns (on the order of 30-100 watts) due to what
> appears to be the severe negative effects of centrifugal force on the
> rider's physiology - specifically, it's much harder for the circulatory
> system to pump blood back to the heart under heavy, positive G forces
> (this is why jet fighter pilots wear G-suits). And this results in
> lower wattage output in the turns.
>
> How do you people refute this data?
>
> spaced like this had Bob done a 4km TT on a flat, straight 4km course.
> I mean not even a cyclist with Tourette's Syndrome would have a wattage
> graph like that on a straight, flat course. So it's obviously caused by
> the turns.
>
> This is a new revelation that nobody else has mentioned except me.
>
> Although all this proves is a cyclist outputs less watts in a velodrome
> turn at maximum effort due to the severe negative physiological effects
> caused by higher G's in a velodrome turn. (It doesn't really clarify
> whether you will go slower in a velodrome turn at constant wattage,
> appears a rider cannot even keep constant wattage in a velodrome turn
> even if he wanted unless it was well below max. But nobody really cares
> about what happens at low to medium wattage outputs anyway.
>
> This graph also appears to show you actually do go slower in a velodrome
> turn at maximum effort, as the onset of increasing speed spikes are in
> almost perfect synchronicity with the end of wattage lows (there appears
> to be a small lag effect).
>
> This is a huge victory for the gorilla's velodrome slower-in-a-turn
> camp, as nobody really expected to see turns causing such a huge
> negative effect on wattage output. It appears that the physics of a
> turn itself might not even be relevant to determining speed in a
> velodrome turn.
>
> You guys are on the canvas and the ref is
> counting...one...two...three....four....
>
> Get up Rocky, get up!
>
>
>
> Velodrome Turn Expert
> San Diego Zoo
Dumbass,
Your *wheels* tend to speed up in the turn for two reasons:
1) you give up potential energy and gain kinetic energy by leaning
over, and
2) your center of resistance (which is primarily aerodynamic in nature)
and your center of mass travel a shorter distance than your wheels.
Since track bikes use a fixed gear, the tendency for the wheels to
accelerate means that your cadence must also increase, which in turn
makes it more difficult to continue to apply "full gas". Experienced
riders are able to minimize this tendency by conciously pedaling harder
in the turns, as shown here:
http://www.fixedgearfever.com/downloads/TrackApplicationsForAPowermeter.ppt#275,21,Variation
in power in turns and straights during 3 km pursuit
However, if you look closely enough you will always be able to spot
small, psuedo-sinusoidal variations in power. This could be interpreted
to mean that it simply cannot be prevented no matter how hard one
tries. However, it could also be interpreted to mean that an absolutely
isopower effort is *not* optimal, because it would result in greater
variations in velocity (both real and apparent).
Andy Coggan
Gabe Brovedani
> MagillaGorilla wrote:
> {Quack, quack, quack}
>
> Ladies and gentlemen of this supposed newsgroup, the monkey
>
> Bob Schwartz
Well damn it, I finally get it. Thank you. I was holding off on the
drinking till I understood it all, and now I'm drinking.
Gabe
P.S. I was on vacation, what's up with the Livedrunk jerseys?
MagillaGorilla
I don't want to do it because it's a waste of time and because everytime
you guys see a physics calculation you automatically assume that it
describes everything that is occurring in a turn, and I'm not going to
feed into that misconception.
The equation for a turn is very complex.
Magilla
MagillaGorilla
> Michael Press wrote:
>
>> Magilla wrote:
>>
>>> There's also a lag effect in there which I don't feel like explaining
>>> now because I'm eating dinner.
>
>
> To fair approximation, M v d v / d t = p - K v^3, for K which depends on
> aerodynamics, where p is power, v is velocity, and M is system mass.
> Since d v / dt, which is acceleration, is not zero, If acceleration
> were very small, then to decent approximation, v = (p / K)^(1/3) -- no
> lag. But if acceleration is significant, power goes into and comes out
> of kinetic energy changes ( M v dv = d(M v^2 / 2) ) in addition to to
> supporting wind resistance.
>
>> Calculate the g-force on a track rider in a turn.
The lag comes from the body's delayed ability to translate the effects
of g-force into a reduced wattage output on a turn and then when the
rider exits a turn there is another delay to get back to normal
physiology. The negative physiologicial affects of a turn do not
immediately disappear the moment a rider's front wheel hits the
straightaway. How long this delay is I don't know. Your power (p) is
going to be reduced BECAUSE OF THE TURN, but that reduction in speed
will also last into the straightaway.
We would need to determine physiological wattage loss empirically
through SRM data from an elite rider.
>
> I already did in the countersteering thread:
>
> Consider a 250 meter track, with 150 meters in corners, and 100 meters
> in straights. If the corners are semicircular, they have a radius of R
> = (150 meters / 2 pi). If the bike center-of-mass (COM) is going v = 60
> km/hr = 16.7 m/sec, it is experiencing a centrifugal acceleration
> relative to gravity of (v2/R g) = 1.19 (I'll define this as alpha). Then
> the total acceleration ("g-forces") is g sqrt(1 + alpha^2) = 1.55 g.
>
> If the speed is 45 kph, then this becomes alpha = 0.67, yielding instead
> 1.20 g.
A 165 lbs. rider weighs 256 pounds in a turn at 60 km/hr. This weight
increase happens in every turn.
Magilla
Bob Schwartz
> http://www.fixedgearfever.com/downloads/TrackApplicationsForAPowermeter.ppt#275,21,Variation
> in power in turns and straights during 3 km pursuit
Those aren't fatty master medals draped all over the kid,
are they?
Bob Schwartz
Alex Simmons
I needed a good laugh and this thread was a pearler....
OP - How about riding a pursuit with a power meter and seeing for
yourself? That's what I do.
The natural tendency of power to vary through the transitions in/out of
turns is more difficult to control the shorter the track for all good
reasons Dr Coggan outlines. Indeed it is an area of pursuiting
improvement that my power meter data has identified for me (but
secondary to working on the engine and aero).
In team pursuiting, experienced riders know the slight variations that
occur in the transitions and anticipate and adjust pedal pressure
accordingly so that they don't run up on the wheel infront or let gaps
form.
Michael Press
<y7vrh.50141$wc5....@newssvr25.news.prodigy.net>,
Dan Connelly <d_j_c_o_n_n_e_l@y_a_h_o_o_._c_o_m>
wrote:
> Michael Press wrote:
I got two results. Both are exactly the acceleration on
the cyclists body that he must resist.
* The general result you derived: total acceleration
the rider experiences in a banked turn
= g * sqrt(v^4/(g * R)^2 + 1).
* Total acceleration the rider experiences in a banked
turn when the centripetal acceleration balances the
gravitational acceleration tending to tip over the
rider. In this case the bicycle vertical axis is
perpendicular to the track and the reaction force of
the track on the contact patches is also perpendicular
to the track.
= g / cos b.
When I said
> > Calculating the g-load with the formula g / cos b is sufficient.
I was supposed to add `for all practical purposes,
since the rider usually takes the line where speed and
bank angle minimize the transverse reaction force at
the contact patches.'
--
Michael Press
Michael Press
MagillaGorilla <Magilla...@zoo.com> wrote:
> sl wrote:
>
> > In article <1168993984.7...@m58g2000cwm.googlegroups.com>,
> > ilan <ila...@yahoo.com> wrote:
>
> >
> > There is an excellent analysis at www.analyticcycling.com, see the
> > "velodrome" model.
> >
>
> http://www.analyticcycling.com/genmodel/LeanAnalysis.html
>
> I read this page. Fine. Basically he says there's a 1.5 second savings
> per 1 km. By the way, such a "speed increase" would hardly be
> observable on a speedometer unless you looked at the tenths. You people
> are talking about a speed increase in a turn like you have a fucking jet
> rocket that kicks on when you enter a turn.
You brought this up denying that the speed change
exists. Now you are saying "What's all this fuss about?"
--
Michael Press
Michael Press
> Also, I'm not quite sure on this, but I think he needs to be factoring
> in equations with weight and not only mass. Sure the center of mass
> travels less distance, but that center of mass in a turn now weighs
> twice as much as it does on a straightaway. A 75kg rider sustaining
> 2g's in a velodrome turn weighs 150kg in a turn. So even if you shave
> some distance off it's center of mass travel, you are doubling the
> bike/rider weight over that shorter distance. This increase in weight
> will hurt you in any acceleration gains due to lean. He talks about the
> distance gain from lean as if doubling the weight of a rider doesn't
> matter. It does.
Pay attention. Maximum g-load is 1.5 * g. Usually <= 1.4 * g.
--
Michael Press
Michael Press
MagillaGorilla <Magilla...@zoo.com> wrote:
Maybe. The way to resist blood pooling in the
extremities is to, surprise, tense the skeletal
muscles. Would be better to have studies investigating
g-forces on physiology. The babbling of track riders
is, of course, useless.
--
Michael Press
Howard Kveck
Michael Press <rub...@pacbell.net> wrote:
Probably because he now realizes that his arguments have squashed like an
overripe banana. Although some people say overripe bananas are best for making a
smoothie.
--
tanx,
Howard
Never take a tenant with a monkey.
remove YOUR SHOES to reply, ok?
Donald Munro
> Probably because he now realizes that his arguments have squashed like an
> overripe banana. Although some people say overripe bananas are best for making a
> smoothie.
There is some subtle difference between an overripe banana and a rotten
one ? Like different kinds of irony perhaps.
Ryan Fisher
> system to pump blood back to the heart under heavy, positive G forces
pilots have to wear G-suits because they are immobile. the effect wouldnt be
nearly as much on a cyclist due to a) much lower G forces on a velodrome
turn as compared to a fighter jet, b) cyclists are continuously pedaling,
thus contracting muscle groups in the legs, which aid in venous blood flow.
Fred Fredburger
> MagillaGorilla wrote:
> {Quack, quack, quack}
>
> Ladies and gentlemen of this supposed newsgroup, the monkey
> velodrome corners. And he makes a good case. Hell, I almost
> felt pity myself! But, ladies and gentlemen of this supposed
> newsgroup, I have one final thing I want you to consider.
> Ladies and gentlemen, this is Chewbacca. Chewbacca is a Wookiee
> from the planet Kashyyyk. But Chewbacca rides on the planet
> Endor. Now think about it; that does not make sense!
>
> Why would a Wookiee, an eight-foot tall Wookiee, want to ride
> on Endor, on a velodrome with a bunch of two-foot tall Ewoks?
> That does not make sense! How would he ride Madisons with a
> two foot tall partner. But more important, you have to ask
> yourself: What does this have to do with this case? Nothing.
> Ladies and gentlemen, it has nothing to do with this case!
> It does not make sense! Look at me. I'm a usenet troller defending
> BS physics, and I'm talkin' about Chewbacca! Does that make sense?
> Ladies and gentlemen, I am not making any sense! None of this
> makes sense! And so you have to remember, when you're in that
> jury room deliberatin' and conjugatin' the Emancipation
> Proclamation, [approaches and softens] does it make sense? No!
> Ladies and gentlemen of this supposed newsgroup, it does not make
> sense! If Chewbacca rides on Endor, he goes faster in velodrome
> turns! The defense rests.
If Magilla's full of shit, you must acquit?
Dan Connelly
> When I said
>>> Calculating the g-load with the formula g / cos b is sufficient.
> I was supposed to add `for all practical purposes,
> since the rider usually takes the line where speed and
> bank angle minimize the transverse reaction force at
> the contact patches.'
>
It seems to me in a pursuit, riders don't have a luxury of taking any
but the line of minimal distance, which implies riding as close to the
black line as possible.
joseph.sa...@gmail.com
I think this detrimental effect of 1.55G is overrated. Speed skaters on
a 400m oval with 24 meter radius turns also travel at 60km/h. They do
not have the benefit of a bike to hold them up either. Skating is a
weight bearing exercise. Not only do they still have the motor control
to carefully place their skate where it is supposed to go with
comparable G's, they also use the turns to accelerate, partially
because leaning puts them in a position to use powerful muscle groups
that are not as well used on the straights. If these guys can pump out
the power and maintain precise coordination at those sorts of G's, I
don't see it being a problem for cylcists. And short track speed
skaters pull even more G's. I don't know their speeds or track
dimensions, but based on the angle of lean (they often reach out a
semi-extended arm to touch the ice) I suspect the acceleration is much
more than 1.55G and they don't have problems.
Joseph
Donald Munro
> pilots have to wear G-suits because they are immobile. the effect wouldnt be
> nearly as much on a cyclist due to a) much lower G forces on a velodrome
> turn as compared to a fighter jet, b) cyclists are continuously pedaling,
> thus contracting muscle groups in the legs, which aid in venous blood flow.
So make a proposal to the Pentagon for an indoor trainer inside the
cockpit. They could even use it to power the hydraulics when all else
fails...
William Asher
I can see it now, Top Gun II featuring a homoerotic "locker-room"
music video scene where Tom Cruise and Val Kilmer shave their legs to 50
Cent's Outta Control. Maybe they can bring in Mark-Paul Gosselaar as the
D.I. who shows them how to go all the way up to their nut-sack. Which, I
think, hits pretty much all the high notes of RBR for the past 10 years.
Have your people call my people and we can set this up.
--
Bill Asher
Bob Schwartz
> http://www.fixedgearfever.com/downloads/TrackApplicationsForAPowermeter.ppt#275,21,Variation
> in power in turns and straights during 3 km pursuit
Have you done any research on pedal synchronization? That's where
the real publication opportunity lies. Some good work there could
enhance your reputation enough to merit a Chung Chart or two.
Bob Schwartz
Michael Press
<1169140881....@q2g2000cwa.googlegroups.com>,
joseph.sa...@gmail.com wrote:
g-load = g / cos b, where b is the angle of lean.
--
Michael Press
Dan Connelly
>> MagillaGorilla wrote: And short track speed
>> skaters pull even more G's. I don't know their speeds or track
>> dimensions, but based on the angle of lean (they often reach out a
>> semi-extended arm to touch the ice) I suspect the acceleration is much
>> more than 1.55G and they don't have problems.
>
> g-load = g / cos b, where b is the angle of lean.
>
So if they fall over, they're in trouble :).
Dan
Donald Munro
>> g-load = g / cos b, where b is the angle of lean.
Dan Connelly wrote:
> So if they fall over, they're in trouble :).
I always knew there was something in the rbr adrenaline theory.
bdbafh
Dan,
Do you mean, like this?
-bdbafh
Speedskater
Skater path length - 111.12 meter (1/2 meter greater radius than the blocks)
Block radius - 8.0 meter
Skater radius - 8.5 meter (never saw a skater skate this path)
Straight - 28.85 meter
Fastest lap times are sometimes under 8.5 seconds
I have heard claims of 8.2 seconds (hard data is difficult to get)
8.5 seconds may be about 1.75g (but I don't know the skater's true path
length.
Speedskater
> MagillaGorilla wrote:
>> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>>
>> This is an actual graph of what I assume is accurate data from Bob's 4km
>> pursuit ride on a velodrome. It clearly shows that a rider is losing
>> significant watts in turns (on the order of 30-100 watts) due to what
>> appears to be the severe negative effects of centrifugal force on the
>> system to pump blood back to the heart under heavy, positive G forces
> some systems (PowerTap? SRM?) were susceptible to fluctuation from G's.
> Could be my imagination. Why does the speed not track with the watts?
>
> Does someone have video of a kilo or pursuit? Why don't we just have a
> look using the magic of slow-mo to measure how long they are on
> different parts of the track?
>
> Joseph
>
I would also wonder about the "latency" of the system.
It must do some averaging of input values.
"system latency" is the time delay between the input value and the
output data.
Carl Sundquist
"Speedskater" <gra...@cox.net> wrote in message
news:B8vsh.187673$Pv5.1...@newsfe17.lga...
>>
>> Do you know how this data was obtained? I recall seeing someplace that
>> some systems (PowerTap? SRM?) were susceptible to fluctuation from G's.
>> Could be my imagination. Why does the speed not track with the watts?
>>
>> Does someone have video of a kilo or pursuit? Why don't we just have a
>> look using the magic of slow-mo to measure how long they are on
>> different parts of the track?
>>
>> Joseph
>>
> I would also wonder about the "latency" of the system.
> It must do some averaging of input values.
> "system latency" is the time delay between the input value and the output
> data.
If I remember correctly, you can set an SRM to record data at 0.1s
intervals. A frequently overlooked issue is that people tend to forget to
zero the smoothing factor for graphing.
Mark Fennell
> This is a huge victory for the gorilla's velodrome slower-in-a-turn camp,
> as nobody really expected to see turns causing such a huge negative effect
> on wattage output. It appears that the physics of a turn itself might not
> even be relevant to determining speed in a velodrome turn.
Just catching up and I didn't read the whole thread so sorry if it's been
resolved, but a current US National Team track rider told me today that ON
CERTAIN TRACKS the turns do indeed accelerate you if you keep the same
power. Alternatively, backing off will keep the same speed. He's looking for
a power file and if he finds one, I'll post it.
Mark
http://marcofanelli.blogspot.com
Ewoud Dronkert
> A frequently overlooked issue is that people tend to forget to
> zero the smoothing factor for graphing.
Zero is always a very effective smoothing factor.
--
E. Dronkert
gmabroke...@yahoo.com
MagillaGorilla wrote:
> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>
> This is an actual graph of what I assume is accurate data from Bob's 4km
> pursuit ride on a velodrome. It clearly shows that a rider is losing
> significant watts in turns (on the order of 30-100 watts) due to what
> appears to be the severe negative effects of centrifugal force on the
> rider's physiology - specifically, it's much harder for the circulatory
> system to pump blood back to the heart under heavy, positive G forces
> (this is why jet fighter pilots wear G-suits). And this results in
> lower wattage output in the turns.
>
> How do you people refute this data?
>
> turn at maximum effort, as the onset of increasing speed spikes are in
> almost perfect synchronicity with the end of wattage lows (there appears
> to be a small lag effect).
>
> >
> You guys are on the canvas and the ref is
> counting...one...two...three....four....
>
>
in reference to the power vs. speed graph, although I don't have an
answer as to why the power varies so much, I do have a few elementary
questions about just how "clearly" the data illustrates your point.
1. I assume the workout illustrated was conducted on a 250-meter track
as the apparent power cycles are 125 meters in length. If so, why are
there 21 spikes and 20 dips in wattage within the 2K illustrated.
Shouldn't there be 16 of each? 8 laps x 2 turns per lap = 16 (I did
say elementary). If it were a 333-meter track there'd be 12 cycles
over 2K, right? Correct me if I'm wrong, but I don't know of too many
200-meter tracks.
2. Regardless of how long the track actually is, wouldn't the track
length, or at least the turn radii, stay pretty much constant during a
pursuit, and wouldn't that be reflected in the wattage cycles? Why
then do the distances between wattage peaks vary so much (from about 60
to 150 meters). Granted, a little variation might be expected, but
250%....please.
3. As far as the "almost perfect synchronicity between the speed
spikes and wattage lows" is concerned, I'd ask, what graph are you
looking at?? The way I see it, about 1/3 of the time the peaks and
lows are almost perfectly in phase, about 1/3 of the time they're
almost perfectly out of phase and the other times they're somewhere in
between. Oh, wait, my bad, never mind...I guess you're right,
perfectly synchronous after all....dumbass.
Always interesting to see how people will cherry-pick and otherwise
manipulate/contort data to try and support a tenuous theory.
The Gimp