Best way to measure Watts-
cycledogg
season. Which is the best or most accurate way to measure, Powermeter
from the rear hub or SRM from the crank?
Cheers and Happy Holidays,
Rick in Tennessee
MagillaGorilla
You are better off setting aside that $2-3,000 for spare tires and
parts. A power meter won't help you get better and it's very unlikely
the rate limiting factor in your training is 'knowledge' of your power.
Power meters are the lastest fad for a lot of morons and 150-mile/week
cyclists who micromanage their on-bike training and think they're
training scientifically.
In reality, most of your limitations in maximimizing your fitness are
going to be things like money, free time, rest time, daily stress from
your job/school, genetics, diet, etc..
In order to justify the cost of a power meter, it means you have all
these other things under control, which you don't.
So I recommend you put that money into other things that will help your
fitness more than a power meter.
Magilla
rechungR...@gmail.com
> I am considering getting into using watts measured for training this
> season. Which is the best or most accurate way to measure, Powermeter
> from the rear hub or SRM from the crank?
Each has advantages and disadvantages. "Best" depends on your
situation. PT appears to be more precise than SRM Amateur; roughly on
par with SRM Pro.
chiefh...@gmail.com
> cycledogg wrote:
> > I am considering getting into using watts measured for training this
> > season. Which is the best or most accurate way to measure, Powermeter
> > from the rear hub or SRM from the crank?
> > Cheers and Happy Holidays,
> > Rick in Tennessee
>
> You are better off setting aside that $2-3,000 for spare tires and
> parts. A power meter won't help you get better and it's very unlikely
> the rate limiting factor in your training is 'knowledge' of your power.
This is ignorance speaking. In the truest sense of the word.
> Power meters are the lastest fad for a lot of morons and 150-mile/week
> cyclists who micromanage their on-bike training and think they're
> training scientifically.
I do not know of even ONE person who did not improve after getting a
powermeter. It helps you to train better, monitor your training load,
see if you are improving.
There are people who don't want to like power training, and cannot be
convinced of anything.
MagillaGorilla
This is hilarious. We're suppose to believe that you actually witnessed
that riders who got power meters got better and that it was due entirely
to their power meter. Hilarious. This is right up there with a claim
that psychics help solve criminal cases because people have supposeldy
witnessed it.
Riddle me this one, joker-face: Do you think guys from the 1970's ever
rode with other riders who "got better." Or are you the only one?
I also like how you imply that you've isolated the reason for their
improvement as being due solel to their power meter. How do you know it
wasn't due to their EPO injections, their diet, their experience, or
their extra mileage? How did you rule all these other factors out and
come tot he conclusion it was due to their power meter?
Vinokourov, Ullrich, Heras, and Tyler Hamilton also got better after
installing a power meter on their bikes.
You just earned yourself an invitation to the attitude adjustment
cycling camp I'm putting on at the Saulsalito cafe. See you there 3
p.m. this Friday.
Magilla
Bob Schwartz
I used a PowerTap to show that it is possible to
simultaneously cut power and accelerate in a velodrome
turn.
Bob Schwartz
chiefh...@gmail.com
powermeter, tested themselves, and in subsequent years, tested better.
It could be other things of course, but for me, I got a lot better at
training and knowing how to train because of the feedback the
powermeter gives me. I have concrete goals to shoot for.
The original poster should get a powermeter. It makes people train
better. If you don't agree, that's ok. I know it's fun for simpletons
to take the contrarian position.
cycl...@gmail.com
> cycledogg wrote:
> > I am considering getting into using watts measured for training this
> > season. Which is the best or most accurate way to measure, Powermeter
> > from the rear hub or SRM from the crank?
> > Cheers and Happy Holidays,
> > Rick in Tennessee
>
> You are better off setting aside that $2-3,000 for spare tires and
> parts. A power meter won't help you get better and it's very unlikely
> the rate limiting factor in your training is 'knowledge' of your power.
As painful as it is, I have to agree with Magilla. Unless you're a Cat
1 or better the only thing you'll get from a power meter is an empty
wallet. Improved training techniques by hiring a good coach would
improve you a great deal better and faster. Talk to Adam Meyerson.
> Power meters are the lastest fad for a lot of morons and 150-mile/week
> cyclists who micromanage their on-bike training and think they're
> training scientifically.
And they improve not because of the training methods they use but
because they're also racing more. Nothing leads to improved racing
muscles than racing.
MagillaGorilla
Don't pay any attention to this answer. You don't need a power meter
unless you want to be a pro and have the genetics to be a pro.
Otherwise, the only thing you need if you want to get substantially
better is a willingness to endure pain and stare at asphalt for 4 hours
a day.
If for some strange reason you even found the spare time to actually
utilize the data from a power meter and assimilate it into a training
program (a nice little Ph.d. project that should take you 2-3 hours a
day to do properly), then you will find your are wasting your time with
trivial projects when you should be trying to bang some hot chick.
So delete your power meter auction links on ebay and put that money
towards some new Michelin clinchers and save the rest for a few dates
with a hot chick. You will gain more mental and physical motivation
from hitting that than graphing your power curves after every training
ride.
When Lance Armstrong won the world championships at 21, he didn't use a
power meter to do that. When Greg LeMond won.....
And all those jackasses you see on continental teams who have resumes
that read like a manager to a valet service for parking lot criteriums
who use power meters on their rigs - they are just kidding themselves.
The only reason they got them on their bikes is because everyone else
got them.
If you go to a pro race, you'll notice all the pro teams sit around in
the SAME type of folding chair. Do you know why? Because the people in
this sport are so fad-oriented and so cliquish, that whatever someone
else does, they do.
Monkey see, monkey do. Don't be another monkey. Be a gorilla.
Magilla
chiefh...@gmail.com
> cycling camp I'm putting on at the Saulsalito cafe. See you there 3
> p.m. this Friday.
>
> Magilla
Is this a variation of the "I'm faster or better than you so I am
right?" argument?
MagillaGorilla
Listen to me and listen to me good. The original poster should
absolutely NOT get a power meter. He doesn't need a glass of milk. He
needs to learn how to milk a cow.
Magilla
MagillaGorilla
Hey Joker,
Bearing in mind that energy cannot be created or destroyed, where does
this extra energy come from?
You sound like someone who has submitted multiple patent applications
for a perpetual motion machine to the U.S. Patent & Trademark Office in
Washington D.C.
Magilla
Mark & Steven Bornfeld
Hopefully the physics mavens can chime in--it has to do with angular
momentum, but I'm pretty sure Bob is right--of course if power isn't
added then there will be a marked deceleration coming out of the turn.
Steve
--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001
MagillaGorilla
> On Dec 3, 11:27 am, MagillaGorilla <magi...@sandiegozoo.com> wrote:
>
>>cycledogg wrote:
>>
>>>I am considering getting into using watts measured for training this
>>>season. Which is the best or most accurate way to measure, Powermeter
>>>from the rear hub or SRM from the crank?
>>>Cheers and Happy Holidays,
>>>Rick in Tennessee
>>
>>You are better off setting aside that $2-3,000 for spare tires and
>>parts. A power meter won't help you get better and it's very unlikely
>>the rate limiting factor in your training is 'knowledge' of your power.
>
>
> As painful as it is, I have to agree with Magilla. Unless you're a Cat
> 1 or better the only thing you'll get from a power meter is an empty
> wallet. Improved training techniques by hiring a good coach would
> improve you a great deal better and faster. Talk to Adam Meyerson.
See, everyone eventually sticks a weary hand through the cage to give
the gorilla a banana.
Magilla
chiefh...@gmail.com
> absolutely NOT get a power meter. He doesn't need a glass of milk. He
> needs to learn how to milk a cow.
We think the same thing.
Having a powermeter, and learning about the body because training is
suddenly more interesting and rewarding, and seeing what results you
get from your training, and learning why you got dropped in a race,
and learning that you needed to train more by monitoring your CTL, and
realizing you weren't fresh because you didn't letup before that big
race enough, and seeing that after 3 hours of racing your power is way
down and your heart rate is up, and maybe you were dehydrated, so next
time you drink more and examine THAT file and see how you did.
Powermeters are IN MY OPINION, the best way to start really learning
about how to train. It unlocks a whole new world of information, and
yes, you can be a dope and do nothing with it, or you can use your
intelligence, willingness to learn, and curiosity and dig in.
ila...@gmail.com
One thing that I realised when I was deciding whether to buy a power
meter is that the technology is not yet mature, that is, it is quite
likely that, independent of manufacturer, this piece of equipment will
probably not work perfectly and will require a lot of technical work.
For example, even without any other problem, you have to routinely
send the SRM back for calibration, and apart from removing and
installing cranks, who has an extra pair lying around?
With that in mind, I chose the PowerTap because it was accurate, much
cheaper than SRM, and there weren't any wires (I had already
previously ripped wires from 2 speedometers and didn't want to live
through that again). So far, it has worked flawlessly, except for
downloading. After many hours with Saris support, the download cradle
was finally identified as the culprit. 4 months later, downloading is
still not working smoothly, so they are sending me my 4th (!!) cradle
and 2nd CPU. Even though this may look bad, it does show that they are
extremely committed to supporting their product. Once I got to the
right department at Saris, everything went very well. I was quite wary
of SRM, since they never even responded to an e-mail question, which I
sent to test their customer support.
Hopefully, the situation will change with when Quarq and Garmin come
out with their wireless units, which will work with SRM or with the
Quarq sensor. For now, it seems to me that PowerTap is best suited for
training, SRM is probably better for racing, given all the different
wheels you need to use, and also because it works well for the track.
-ilan
Bob Schwartz
http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
My very own Chung Chart. Coggan provides a good explanation.
http://groups.google.com/group/rec.bicycles.racing/msg/e9165fe820602ef4
Bob Schwartz
SLAVE of THE STATE
> season. Which is the best or most accurate way to measure, Powermeter
> from the rear hub or SRM from the crank?
Corrections for systematic errors can be applied, and good results can
be had, but intuitively: If you want to measure power at the hub, buy
a hub sensed meter. If you want to measure power at the crank, buy a
crank sensed meter.
But my primate friend is largely correct. If you've got the 99% of
conditioning extracted from your body (which requires only a bike,
time, and willpower), then you can think of dropping your bucks on a
power meter, if "high" priced gadgets are your thing, and that last 1%
is important to you.
Remember that most races where you will (or have had) a reasonable
shot at winning will be lost because of some bad split-second decision
you make (made), not your power output. /When/ you put out power is
more important than /how much/, for that first 99% of conditioning,
and that requires no gadgets, but simple experience and judicious
reflection.
On the other hand, if you simply like gadgets, then by all means buy
one. Don't get wireless -- there will be a built-in error of a few
percent due to background radiation from the big bang. I think using
energy from the big bang must be against UCI regulations. The UCI is
sort of like the pope, you know. I don't know what happens around
corners though. There is knife-edge diffraction on sharp corners, and
you might slow down.
Personally, I just listen to Highway Star before leaving on rides. It
does 99% of what can be done.
Pete
You are really not interested in accuracy. You are interested in
consistency if you want it at all.
If you buy something that says 250W when you're putting out 200, but
it does it consistently, you'll get the same training benefit of
always knowing how hard you're working (that's relative to your AT
anyway, and you'll have measured that with the same power meter..).
That said, they are so damn expensive - and you do most of your riding
on the same roads, and then you know pretty well how your speed and
power output correspond. Speedo costs about 1/50th of a power meter...
no contest.
Pete
MagillaGorilla
Interpreting power meter data is complex and beyond the scope of most
people, includiing trainers.
You don't need a power meter to ride a bike, race or bike, or get
better. Having one is just another expensive thing that breaks when you
crash.
The money can be better spent on tires and spare parts. A power meter
will not help you go faster because most people don't know how to
interpet the data anyway.
Magilla
Mark & Steven Bornfeld
>
> http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>
> My very own Chung Chart. Coggan provides a good explanation.
>
> http://groups.google.com/group/rec.bicycles.racing/msg/e9165fe820602ef4
>
> Bob Schwartz
Thanks Bob!
MagillaGorilla
Physics 101: Energy cannot be created or destroyed, only changed from
one form to another.
So unless someone in here is Einstein and wants to change the
understanding of modern physics with a new theory on the conservation of
energy, I think it's safe to conclude there is no energy (or speed) gain.
I don't need to ask anyone else's opinion.
You can't gain speed or energy in a turn. Any speed gain you get from
your initial lean into a turn MUST BE lost (plus some) while exiting
that same turn because it takes longer (and more energy) to bring
yourself upright and raise yourself than it would had you ridden that
same distance on a straightaway and never had to lean up or down to
begin with.
On a straightaway, that same energy is put into the pedals. You are
losing substantial amounts of energy in a turn via friction.
Nothing is free in energy equations.
Magilla
Ted van de Weteringe
> Don't get wireless -- there will be a built-in error of a few
> percent due to background radiation from the big bang.
Only for the first three minutes of the race.
Ryan Cousineau
MagillaGorilla <mag...@sandiegozoo.com> wrote:
Even a stopped clock is right twice a day.
--
Ryan Cousineau rcou...@sfu.ca http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing
chiefh...@gmail.com
> people, includiing trainers.
That's just not true.
You just earned yourself an invitation to the powermeter file reading
interpretation camp I'm putting on United Center. See you there 7
p.m. this Friday.
Sandy
news:rcousine-40C5CE.16573903122007@[74.223.185.199.nw.nuvox.net],
Ryan Cousineau <rcou...@sfu.ca> a réfléchi, et puis a déclaré :
Ryan Cousineau rcou...@sfu.ca http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing
I'll work on a new one !
--
Sandy
Verneuil-sur-Seine FR
"Le Vin est la plus saine et la plus hygiénique des boissons."
- Louis Pasteur
That standard should please for a bit.
MagillaGorilla
That time you spend discussing power meter data would be better spent
resting or training.
The most important thing cyclists need to have to improve is motivation
and happiness. Both of those depend on things like financial stability,
job happiness, relationship stress, etc. A power meter doesn't even
make the list.
And to sit here and talk about power meter data in a vacuum as a
function of traiining comes across as incredibly shallow.
There is NOBODY who works a 9-5 job or goes to college and can honestly
claim a power meter will help them more than simply training more or
resting more or being happy more or eating better.
One can accomplish the same thing as a power meter using nothing but
timed intervals up the same climb. You don't need a $2,500 power meter
to figure out your fitness.
If you want to micromanage your cycling training to the point where
you're staring at $2,500 graphs after 6 hour training rides, then you
need to lighten the fuck up before you turn into a Jeff Evanshine headcase.
Magilla
Donald Munro
> So I recommend you put that money into other things that will help your
> fitness more than a power meter.
Dumbass,
Perhaps if you got a power meter you'd be faster around turns.
bdbafh
Gibbs energy is occasionally free, but that would head off the highway
of Newtonian mechanics and over into chemistry, which would probably
lead to the dark side ...
-bdbafh
Donald Munro
> Gibbs energy is occasionally free, but that would head off the highway of
> Newtonian mechanics and over into chemistry, which would probably lead to
> the dark side ...
If its a free lunch its probably andoulette.
Bob Schwartz
> Physics 101:
Dumbass,
You mean Geometry 101, don't you. The largest effect
has nothing to do with physics.
Bob Schwartz
Andrew F Martin
> I am considering getting into using watts measured for training this
> season. Which is the best or most accurate way to measure, Powermeter
> from the rear hub or SRM from the crank?
> Cheers and Happy Holidays,
> Rick in Tennessee
I'd go with the PowerTap SL 2.4 Wireless built onto some decent rims.
I know Bontrager has a good setup (and you can get them in a matched
wheelset). The ability to swap them between bikes without all the
harness is pretty nice.
Note - I don't use power trainer and ChiefHiawatha hates me for it. I
say it's because I'm cheap, but it's really because I don't want to
know that I'm the weakest Cat1 in the country.
Scott
It's not about training more, it's about training better.
Having said that, I have to agree with some of your earlier points.
For example, I agree that for most people a power meter is overkill.
I believe that most people who report great gains using them could
just as easily have achieved those gains with improvements in the
training/resting without a power meter. Perhaps it was having a power
meter that motivated them to train more, or helped them cut out
useless or even counterproductive riding they were doing before, or
whatever. It is much harder to figure out what to do about increasing
your power than just merely knowing what your power is to start with.
Michael Press
Mark & Steven Bornfeld <bornfe...@dentaltwins.com>
wrote:
> Hopefully the physics mavens can chime in--it has to do with angular
> momentum, but I'm pretty sure Bob is right--of course if power isn't
> added then there will be a marked deceleration coming out of the turn.
The center of mass only accelerates when the kinetic
energy changes. This can occur if the COM changes
altitude, or if the rider changes power input. In a
purely kinematic analysis where the presence or absence
of a banked turn acts perpendicular to the velocity we
have zero acceleration.
The center of mass continues with the same instantaneous
speed as it did on the straight.
This assumes that the COM remains on the same gravitational
equipotential surface: i.e. the lean of the system combined
with the change in altitude of the contact patch combine to
leave the COM at the same altitude.
Given this situation with the COM maintaining the same
speed in the turn, as it must by conservation of energy,
the contact patch follows a concentric path with larger
radius than the path of the COM, and must travel faster.
This is a purely geometric-kinematic argument. Taking
the dynamics into account is a task well beyond the
native and learned capacity of a monkey.
--
Michael Press
Michael Press
MagillaGorilla <mag...@sandiegozoo.com> wrote:
The speed of the center of mass does not change.
The difference in radius of curvature of the COM
path and the contact patch path demand that the
contact patch travel faster than the COM.
>
> I don't need to ask anyone else's opinion.
Ah, you argue from opinion.
> You can't gain speed or energy in a turn. Any speed gain you get from
> your initial lean into a turn MUST BE lost (plus some) while exiting
> that same turn because it takes longer (and more energy) to bring
> yourself upright and raise yourself than it would had you ridden that
> same distance on a straightaway and never had to lean up or down to
> begin with.
>
> On a straightaway, that same energy is put into the pedals. You are
> losing substantial amounts of energy in a turn via friction.
>
> Nothing is free in energy equations.
You are confused. Study some geometry and physics.
This stuff is simple. Then you can argue the hard stuff.
--
Michael Press
MagillaGorilla
No, I mean physics. Energy equations and thermodynamics are a part of
physics.
Geometry is really just a science of logic more than anything else.
I think the largest factor in a velodrome turn is not the center of mass
calculation.
Think about what a turn in a velodrome really is...it's a 180-degree
change in inertia.
Imagine if you had a semi truck that weighed 40 tons and it was heading
directly towards you. And then imagine is you imparted some force onto
that truck that would cause it to turn 180 degrees away from you. That
force you would need would have to be tremendous to cause thhe truck to
divert from its inertial course (which is to keep going straight).
In a velodrome, you are taking 200 pounds of mass at 30 mph and changing
its vector velocity 180 degrees. Any person of science worth their salt
will tell you that in order to do this it requires a huge energy imput
(energy loss).
This energy loss occurs in the form of friction and increased rolling
resistance. Since no such energy llosss occurs when a rider is going
straight, it's pretty easy to suspect that you cannot be going faster in
a turn than a straightaway.
Now the center of mass argument is interesting and definitely appears to
be a gain. But as Holman calculated, it doesn't even compensate for the
loss of watts you get from increased rolling resistance. Add to that
about 7 other negatives and it seems intuitive that a turn is going to
cause a net loss in energy (and speed).
The bottom line is there are too many people in here who don't appear to
fully appreciate the concept that you cannot change the Momentum (M = m
x v) of an object 180 degrees and conserve its kinetic energy. Changing
the direction of a moving mass 180 degrees requires a tremendous input
of energy. And in the case of a cyclist on a velodrome, that energy has
to come from the rider.
The idea that leaning in a turn will somoehow compensate for this energy
loss means that you are trying to sell me on a sort of perpetual motion
machine velodrome where 100% of energy lost is recyled because of
leaning and that furthermore, the rider is actually gaining energy.
Nobody who took physics and actually understands it talks about
"gaining" energy unless you can explain where this extra energy comes
from. Leaning and reducing the distance your COM would have to travel
is not an energy gain. It's a cherry picked observation that although
shows a small SPEED gain for a given wattage when ISOLATED as a
variable, it fails to take into account that when you lean in a turn,
you are also doing like 10 severely negative things that SUBTRACT from
your energy and must therefore also subtract from your speed.
I don't get the feeling that you people truly appreciate the complex
physics that is occuring in a turn.
Magilla
Andy Coggan
<bornfeldm...@dentaltwins.com> wrote:
> Bob Schwartz wrote:
>
> >http://anonymous.coward.free.fr/rbr/schwartzpursuit.png
>
> > My very own Chung Chart. Coggan provides a good explanation.
>
> >http://groups.google.com/group/rec.bicycles.racing/msg/e9165fe820602ef4
>
> > Bob Schwartz
>
> Thanks Bob!
>
> Steve
Ditto!
Andy Coggan
Andy Coggan
> the only thing you need if you want to get substantially
> better is a willingness to endure pain and stare at asphalt for 4 hours
> a day.
Is that how you made it up to cat. 1? Oh, right...you were never more
than pack fodder in local cat. 2 races, and couldn't break the hour in
a 40 km TT despite all my help. Now maybe if you *had* used a
powermeter for a few years, you could achieved these goals...
Andy Coggan
Andy Coggan
> even without any other problem, you have to routinely
> send the SRM back for calibration
This is not true.
Andy Coggan
SLAVE of THE STATE
wrote:
Now I'm thinking about that very annoying sprint to the first
corner.
Ryan Cousineau
MagillaGorilla <mag...@sandiegozoo.com> wrote:
> Bob Schwartz wrote:
>
> > MagillaGorilla wrote:
> >
> >> Physics 101:
> >
> >
> > Dumbass,
> >
> > You mean Geometry 101, don't you. The largest effect
> > has nothing to do with physics.
> >
> > Bob Schwartz
>
>
> No, I mean physics. Energy equations and thermodynamics are a part of
> physics.
>
> Geometry is really just a science of logic more than anything else.
>
> I think the largest factor in a velodrome turn is not the center of mass
> calculation.
>
> Think about what a turn in a velodrome really is...it's a 180-degree
> change in inertia.
>
> Imagine if you had a semi truck that weighed 40 tons and it was heading
> directly towards you. And then imagine is you imparted some force onto
> that truck that would cause it to turn 180 degrees away from you. That
> force you would need would have to be tremendous to cause thhe truck to
> divert from its inertial course (which is to keep going straight).
>
> In a velodrome, you are taking 200 pounds of mass at 30 mph and changing
> its vector velocity 180 degrees. Any person of science worth their salt
> will tell you that in order to do this it requires a huge energy imput
> (energy loss).
Magilla, you dumb ape: it requires a huge force, not energy. The force
is provided by the velodrome rising up to meet you and spit you through
the corner.
Your logic probably has you wondering what will happen when the gravity
runs out.
Not that you're doing anything but trolling, but for the benefit of any
lurkers, I'd point out that you're measuring the ground speed several
feet from the centre of mass. Here's the stupidest-case scenario of
that: put a couple pounds of weight on the end of a strong metre-long
cable, grab the other end, and start spinning in a circle. You'll be
able to get the weight going very fast with little energy input. The
biggest limiting factor will be your capacity for holding in your lunch
while spinning in little circles.
--
Bob Schwartz
> I don't get the feeling that you people truly appreciate the complex
> physics that is occuring in a turn.
You mean geometry, don't you?
Bob Schwartz
Tom Kunich
news:ce820daf-3934-4be5...@x69g2000hsx.googlegroups.com...
For all those who think of Andy as God - he's wrong. Ilan is a college
professor who expects the meter to read correctly. Andy is a far more
practical person who thinks that inaccuracy is OK as long as it's a
constant.
MagillaGorilla
Miguel Indurain, Eddy Merckx, Bernard Hinault, Greg LeMond, Chris
Boardman, Obree....none of your heroes used a power meter.
Magilla
MagillaGorilla
Dude,
I hate to tell you but the only conclusion we came to was that Bob was
easing up in the turns due to inexperience. Because of this noise
factor, I conceded that these graphs do not prove that you go slower in
turns (even though at face value, they show a definitive, consistent
power loss in the turns).
Magilla
Howard Kveck
For what it's worth, Boardman did use SRM cranks. Just sayin'.
--
tanx,
Howard
Safe when used as directed...
remove YOUR SHOES to reply, ok?
seven-22
> Miguel Indurain, Eddy Merckx, Bernard Hinault, Greg LeMond, Chris
> Boardman, Obree....none of your heroes used a power meter.
>
> Magilla
Although I agree with some of your arguments, please stop using the
one quoted above. It discredits you. Lemond was one of the first
pro's to use a powermeter.
http://www.pezcyclingnews.com/?pg=fullstory&id=3660
Eddy wasn't riding on Michelin pro race tires. Why are you?
A powermeter is simply another tool to give feedback to the rider. It
is not the silver bullet. My time is up...have fun.
Kyle Legate
amit....@gmail.com
>
> For all those who think of Andy as God - he's wrong. Ilan is a college
> professor who expects the meter to read correctly. Andy is a far more
> practical person who thinks that inaccuracy is OK as long as it's a
> constant.
but they both need koach kunich to put words in their mouth.
Donald Munro
>>>> Don't get wireless -- there will be a built-in error of a few percent
>>>> due to background radiation from the big bang.
Ted van de Weteringe wrote:
>>> Only for the first three minutes of the race.
SLAVE of THE STATE wrote:
>> Now I'm thinking about that very annoying sprint to the first corner.
Kyle Legate wrote:
> Usually, that's the only thing I could win.
Team FTL, at least in the first few seconds of the race.
Mark & Steven Bornfeld
I actually almost think I understand that--thank you, Michael!
Steve
--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001
cycl...@gmail.com
<bornfeldm...@dentaltwins.com> wrote:
>
> Hopefully the physics mavens can chime in--it has to do with angular
> momentum, but I'm pretty sure Bob is right--of course if power isn't
> added then there will be a marked deceleration coming out of the turn.
But you do that unconciously since the whole idea of racing is to "add
power". You have heard the term, "Accelerating out of the turn"
haven't you?
Mark & Steven Bornfeld
Sure.
cycl...@gmail.com
<bornfeldm...@dentaltwins.com> wrote:
> Michael Press wrote:
>
> > The center of mass only accelerates when the kinetic
> > energy changes. This can occur if the COM changes
> > altitude, or if the rider changes power input. In a
> > purely kinematic analysis where the presence or absence
> > of a banked turn acts perpendicular to the velocity we
> > have zero acceleration.
>
> > The center of mass continues with the same instantaneous
> > speed as it did on the straight.
>
> > This assumes that the COM remains on the same gravitational
> > equipotential surface: i.e. the lean of the system combined
> > with the change in altitude of the contact patch combine to
> > leave the COM at the same altitude.
>
> > Given this situation with the COM maintaining the same
> > speed in the turn, as it must by conservation of energy,
> > the contact patch follows a concentric path with larger
> > radius than the path of the COM, and must travel faster.
> > This is a purely geometric-kinematic argument. Taking
> > the dynamics into account is a task well beyond the
> > native and learned capacity of a monkey.
>
> I actually almost think I understand that--thank you, Michael!
The long and the short of it is that the center of mass of the person
is going whatever speed when you enter the banked turn. Because the
center of mass is going that speed and takes a SHORTER path than the
wheels of the bike the bike itself and anything below the center of
mass has to accelerate to keep up.
As you come out of the turn and bring the bike erect the center of
mass continues on at the speed it was going while the bicycle below
him slows up to his speed.
rechungR...@gmail.com
> "Andy Coggan" <acog...@earthlink.net> wrote in message
> > On Dec 3, 3:39 pm, ilan...@gmail.com wrote:>
>
> >> even without any other problem, you have to routinely
> >> send the SRM back for calibration
>
> > This is not true.
>
> For all those who think of Andy as God - he's wrong. Ilan is a college
> professor who expects the meter to read correctly. Andy is a far more
> practical person who thinks that inaccuracy is OK as long as it's a
> constant.
The SRM does not need to be sent back routinely for calibration.
Andy Coggan
Tom Kunich
news:66ebb3dc-e48b-4ae1...@b40g2000prf.googlegroups.com...
And yet two of them will not give you the same answer on the same bike.
rechungR...@gmail.com
> > The SRM does not need to be sent back routinely for calibration.
>
> And yet two of them will not give you the same answer on the same bike.
You know this because you've been putting two SRMs on the same bike at
the same time?
Ted van de Weteringe
> Your logic probably has you wondering what will happen when the gravity
> runs out.
Donald Munro
>> And yet two of them will not give you the same answer on the same bike.
rechungREMOVETHIS wrote:
> You know this because you've been putting two SRMs on the same bike at the
> same time?
Must have been a tandem.
cycl...@gmail.com
I know this because SRM says so.
rechungR...@gmail.com
Iran stopped its nuclear weapons program in 2003. I know this because
sixteen American intelligence agencies say so.
Andy Coggan
> <rechungREMOVET...@gmail.com> wrote in message
They will if properly calibrated (which is something that you can do
yourself).
By way of example: my wife has SRMs on both her road and track bikes.
If you plot her maximal power vs. duration using the two sets of data,
the lines are practically superimposable (i.e., generally within a
watt or two), at least at/across all durations where she has made a
truly maximal effort on each bike.
Andy Coggan
Andy Coggan
> For all those who think of Andy as God - he's wrong. Ilan is a college
> professor who expects the meter to read correctly. Andy is a far more
> practical person who thinks that inaccuracy is OK as long as it's a
> constant.
So I'm curious, Tom - what is that you think I do for a living?
Andy Coggan
MagillaGorilla
> On Dec 3, 11:01 pm, MagillaGorilla <magi...@sandiegozoo.com> wrote:
>
>>chiefhiawa...@gmail.com wrote:
>>
>>>>Interpreting power meter data is complex and beyond the scope of most
>>>>people, includiing trainers.
>>
>>>That's just not true.
>>
>>>You just earned yourself an invitation to the powermeter file reading
>>>interpretation camp I'm putting on United Center. See you there 7
>>>p.m. this Friday.
>>
>>That time you spend discussing power meter data would be better spent
>>resting or training.
>>
>>The most important thing cyclists need to have to improve is motivation
>>and happiness. Both of those depend on things like financial stability,
>>job happiness, relationship stress, etc. A power meter doesn't even
>>make the list.
>>
>>And to sit here and talk about power meter data in a vacuum as a
>>function of traiining comes across as incredibly shallow.
>>
>>There is NOBODY who works a 9-5 job or goes to college and can honestly
>>claim a power meter will help them more than simply training more or
>>resting more or being happy more or eating better.
>>
>>One can accomplish the same thing as a power meter using nothing but
>>timed intervals up the same climb. You don't need a $2,500 power meter
>>to figure out your fitness.
>>
>>If you want to micromanage your cycling training to the point where
>>you're staring at $2,500 graphs after 6 hour training rides, then you
>>need to lighten the fuck up before you turn into a Jeff Evanshine headcase.
>>
>>Magilla
>
>
> It's not about training more, it's about training better.
>
> Having said that, I have to agree with some of your earlier points.
> For example, I agree that for most people a power meter is overkill.
> I believe that most people who report great gains using them could
> just as easily have achieved those gains with improvements in the
> training/resting without a power meter. Perhaps it was having a power
> meter that motivated them to train more, or helped them cut out
> useless or even counterproductive riding they were doing before, or
> whatever. It is much harder to figure out what to do about increasing
> your power than just merely knowing what your power is to start with.
>
-------
I think if you train 400 miles a week and are on the verge of being a
pro, you might be able to benefit from knowing what type of power you
can generate in order to match (or exceed) your fiteness from previous
years.
But as everyone who has seriously trained knows, when you start piling
on the miles, what matters most is what is going on in your life off the
bike.
If you have to work 50 hours a week and can only train 2 hours at night,
I don't know why you think getting a power meter (as opposed to a new
job) is the way to make the most significant impact on your riding career.
There's too many people who talk about training in a vacuum as if it
starts when you clip in and ends wen you clip out. In reality, it's a
24/7 thing. If you work as a waitor and have to stand on your feet for
8 hours a day, it would be strange to invest your waitor tips in a power
meter because that's not the 'problem' in your training regiumen.
Also, everyone who's seriously trained knows that elite fitness is
fleeting and it's not even something that is necessarily desirable to
have because the effort and time required to get there and keep it at
that level is an enormous stress. That's what has led to the concept
of peaking.
I get concerned when you have people using power meters to maximize
their fitness on every ride. Most people would be better off riding
liesure centuries during base training and not even worrying about their
power.
Second, knowledge of your power has almost nothing to do with you
ability to increase it.
Basically when you assimilate all the factors that are required to make
oneself a better cyclist, a power meter is quite insignificant. It
might even be harmful because it's just another expense to an already
ridiculously expensive sport. And the extra financial stress is bad for
fitness. The extra data is probably superfluous.
Anybody who argues that a power meter makes them a better rider needs to
ask themselves how all the pros from 1900-1995 got better without a
power meter.
The bottom line is if Bernard Hinault never used a power meter, then
chances are you don't need one either.
Magilla
SLAVE of THE STATE
> <rechungREMOVET...@gmail.com> wrote in message
http://www.ukas.com/information_centre/technical/technical_uncertain.asp
http://www.google.com/search?hl=en&q=measurement+uncertainty
You're saying they are out of spec?
SLAVE of THE STATE
I learned the the checkmate thread that gods don't need to work for a
living. It goes with the supernatural territory.
I'm not sure what my pet primates do other than 3 hour afternoon
training rides. Are you one of my pet primates?
BeeCharmer
>
> If you go to a pro race, you'll notice all the pro teams sit around in
> the SAME type of folding chair. Do you know why?
Because they got 'em for free?
MagillaGorilla
> In article <fj4f38$s60$1...@aioe.org>,
> MagillaGorilla <mag...@sandiegozoo.com> wrote:
>
>
>>Bob Schwartz wrote:
>>
>>
>>>MagillaGorilla wrote:
>>>
>>>
>>>>Physics 101:
>>>
>>>
>>>Dumbass,
>>>
>>>You mean Geometry 101, don't you. The largest effect
>>>has nothing to do with physics.
>>>
>>>Bob Schwartz
>>
>>
>>No, I mean physics. Energy equations and thermodynamics are a part of
>>physics.
>>
>>Geometry is really just a science of logic more than anything else.
>>
>>I think the largest factor in a velodrome turn is not the center of mass
>>calculation.
>>
>>Think about what a turn in a velodrome really is...it's a 180-degree
>>change in inertia.
>>
>>Imagine if you had a semi truck that weighed 40 tons and it was heading
>>directly towards you. And then imagine is you imparted some force onto
>>that truck that would cause it to turn 180 degrees away from you. That
>>force you would need would have to be tremendous to cause thhe truck to
>>divert from its inertial course (which is to keep going straight).
>>
>>In a velodrome, you are taking 200 pounds of mass at 30 mph and changing
>>its vector velocity 180 degrees. Any person of science worth their salt
>>will tell you that in order to do this it requires a huge energy imput
>>(energy loss).
>
>
> Magilla, you dumb ape: it requires a huge force, not energy. The force
> is provided by the velodrome rising up to meet you and spit you through
> the corner.
>
Correct, that force causes increased friction, which increases rolling
resistance leading to the decrease of kinetic energy (speed) of your
bicycle. I never said a rider loses energy in a turn (and if I did, I
was just being sloppy in that post). Although a rider does lose energy
because of physiological negatives (both circulatory and vertigo), I
acknowledge that you weren't debating that.
A rider also loses a slight amount of energy by having to lean up in the
exit of every turn. Again, we weren't talking about that here so I
won't try to attribute that to you in this debate.
Otherwise, pedaling in a turn vs. a straightaway wouldn't amount to a
measurable energy change.
But the kinetic energy of your bike IS decreased in a turn due to these
forces, causing a decrease in speed because kinetic energy is converted
to friction (heat). Whether the CoM factor cancels out all these
negatives is what we're debating.
Magilla
MagillaGorilla
Is your wife a MILF?
Magilla
SLAVE of THE STATE
Forget the wattmeter. Everyone wants to know how you got your wife so
well calibrated. You could write your own version of "Women are from
Venus" and retire off the profits.
MagillaGorilla
> In article <fu_4j.2290$3W.22@trndny04>,
> Mark & Steven Bornfeld <bornfe...@dentaltwins.com>
> wrote:
>
>
>>MagillaGorilla wrote:
>>
>>>Bob Schwartz wrote:
>>>
>>>
>>>>MagillaGorilla wrote:
>>>>
>>>>
>> Hopefully the physics mavens can chime in--it has to do with angular
>>momentum, but I'm pretty sure Bob is right--of course if power isn't
>>added then there will be a marked deceleration coming out of the turn.
>
>
> The center of mass only accelerates when the kinetic
> energy changes. This can occur if the COM changes
> altitude, or if the rider changes power input. In a
> purely kinematic analysis where the presence or absence
> of a banked turn acts perpendicular to the velocity we
> have zero acceleration.
>
> The center of mass continues with the same instantaneous
> speed as it did on the straight.
>
> This assumes that the COM remains on the same gravitational
> equipotential surface: i.e. the lean of the system combined
> with the change in altitude of the contact patch combine to
> leave the COM at the same altitude.
>
> Given this situation with the COM maintaining the same
> speed in the turn, as it must by conservation of energy,
> the contact patch follows a concentric path with larger
> radius than the path of the COM, and must travel faster.
> This is a purely geometric-kinematic argument. Taking
> the dynamics into account is a task well beyond the
> native and learned capacity of a monkey.
>
True, you are conserving angular momentum in a turn which results in the
increase in speed at the wheel track. All I'm addint to that equation is:
1). Without an increase in energy, you're speed cannot increase that
much from a philosophical standpoint.
2.) A turn causes many negative things to happen, some of which are
physiological and hurt your wattage output, and others which are physics
in nature. None of these negative things happen in a straightaway and
all of them subtract from any gain you willl get by decreaseing the CoM
distance.
3.) When you factor in the CoM argument with the all the negatives, I
submit to you that not only will you see a drop in speed in a turn, but
a drop in wattage.
4.) You are betting on a longshot horse when you say you are confident a
bike will go faster around a turn once you see it's apparent that both
your wattage and speed will be decreased because of negative factors
that do not occur in a straightaway. As for the CoM factor, I think
it's a red herring. It occurs alright, but it's not that significant
and I'm not sure why everyone latches on to it as the Hail Mary factor.
You people in here talk about a velodrome turn as if it imparts the same
kinetics as an Apollo lunar module that uses the moon's gravitational
pull to slingshot it around back to earth.
Plus, the fact that in every empirical example I can think of - track
runners, airplanes, NASCAR, motorcycle racing, speed skaters,
speedboats....every single one of them goes slower around a turn.
But somehow I'm suppose to fucking believe cycling is different.
Somehow, you people want everyone to believe that cycling has different
physics involved in a turn from these other real-world examples when in
fact it really doesn't.
Magilla
Ryan Cousineau
<8a51d2c0-53e9-4773...@a39g2000pre.googlegroups.com>,
Have as many pets as you want, Slave, but remember: you're working for
Robert.
--
Ryan Cousineau rcou...@sfu.ca http://www.wiredcola.com/
"My scenarios may give the impression I could be an excellent crook.
Not true - I am a talented lawyer." - Sandy in rec.bicycles.racing
Tom Kunich
news:a332ea6b-c146-4e2a...@p69g2000hsa.googlegroups.com...
> On Dec 5, 10:28 pm, "Tom Kunich" <cyclintom@yahoo. com> wrote:
>> > The SRM does not need to be sent back routinely for calibration.
>>
>> And yet two of them will not give you the same answer on the same bike.
>
> They will if properly calibrated (which is something that you can do
> yourself).
Andy, what are you calibrating to?
> By way of example: my wife has SRMs on both her road and track bikes.
> If you plot her maximal power vs. duration using the two sets of data,
> the lines are practically superimposable (i.e., generally within a
> watt or two), at least at/across all durations where she has made a
> truly maximal effort on each bike.
Why do I have the idea that you setup and maintain them?
Tom Kunich
To tell you the truth Andy, I haven't a clue how exercise physiologists make
a living unless they teach.
The problem with your answer and the rest of the world appears to be
something that you can't grasp - that hardly anyone would or would care to
maintain and calibrate a meter every run. Ilan actually expects the thing to
read properly every time he takes it out or at least within a couple of
percent of correct.
The two or three SRM's I saw had readings that didn't make any sense at all.
Obviously they hadn't been calibrated.
So, would you expect to calibrate your speedometer on your car every time
you went out?
Howard Kveck
> Plus, the fact that in every empirical example I can think of - track
> runners, airplanes, NASCAR, motorcycle racing, speed skaters,
> speedboats....every single one of them goes slower around a turn.
The reason that all of those examples slow down for a turn is that they are going
faster than the limits of traction allow if they didn't slow. A bike on a banked
track does not come close to the limits of traction. Well, I question whether track
runners actually do slow for turns.
> But somehow I'm suppose to fucking believe cycling is different.
Yep.
--
tanx,
Howard
Safe when used as directed...
remove YOUR SHOES to reply, ok?
chiefh...@gmail.com
> Anybody who argues that a power meter makes them a better rider needs to
> ask themselves how all the pros from 1900-1995 got better without a
> power meter.
Truly a dumb argument.
chiefh...@gmail.com
> something that you can't grasp - that hardly anyone would or would care to
> maintain and calibrate a meter every run. Ilan actually expects the thing to
> read properly every time he takes it out or at least within a couple of
> percent of correct.
Do you realize how easy it is to calibrate the Powertap, and how
little you need to calibrate an SRM?
I would also like to offer that you are riding Ilan's cock so hard you
should probably be wearing a helmet.
Tom Kunich
news:3148a3d0-ca55-4246...@x69g2000hsx.googlegroups.com...
>
> Do you realize how easy it is to calibrate the Powertap, and how
> little you need to calibrate an SRM?
By all means explain to us how you calibrate a Powertap or an SRM.
And of course loudmouth little babies such as yourself seem to abound where
ever they can remain anonymous.
chiefh...@gmail.com
> By all means explain to us how you calibrate a Powertap or an SRM.
I said how easy to do a powertap: In watts mode you hold down the
right button for three seconds, coast, hold it down again for three
seconds, then hit it again to get back into watts mode. done.
I said how little you need to calibrate an SRM, not how easily.
> And of course loudmouth little babies such as yourself seem to abound where
> ever they can remain anonymous.
What's the difference in anonymous versus real name? If I were to use
my real name and call you a crazy old man who probably has a very very
very sad lonely life, am I supposed to fear some sort of repercussion?
I really don't get why this handle vs real name thing matters to you,
or anyone else for that matter.
Bob Schwartz
> But somehow I'm suppose to fucking believe cycling is different.
> Somehow, you people want everyone to believe that cycling has different
> physics involved in a turn from these other real-world examples when in
> fact it really doesn't.
Geometry. Not physics. Dumbass.
Bob Schwartz
amit....@gmail.com
> "Andy Coggan" <acog...@earthlink.net> wrote in message
>
> news:8c6b7816-610f-4db2...@w34g2000hsg.googlegroups.com...
>
> > On Dec 4, 11:22 pm, "Tom Kunich" <cyclintom@yahoo. com> wrote:
>
> >> For all those who think of Andy as God - he's wrong. Ilan is a college
> >> professor who expects the meter to read correctly. Andy is a far more
> >> practical person who thinks that inaccuracy is OK as long as it's a
> >> constant.
>
> > So I'm curious, Tom - what is that you think I do for a living?
>
> To tell you the truth Andy, I haven't a clue how exercise physiologists make
> a living unless they teach.
research, ever heard of it ?
MagillaGorilla
I suggest your go rent the '84 Tour video and take a close look at
Bernard Hinault's rig after Fondriest's sissy toy* crashed him in the
break and the Badger got up with blood pouring from his head to win that
race. You won't see a computer the size of a Univac mainframe clamped
onto his Cinellis.
Hinault use to go out clubbing during the Tour to fuck with people. He
didn't sit in his room at the team hotel with some lambchop sideburn
lookin' Drew Carey manager and stare at power curves on a laptop to try
to figure out how to crush the legs of his competitors.
You people better cancel your subscription to Bicycling Magazine or I'll
cancel it for you.
Magilla
*Stephanie Bauer
amit....@gmail.com
> <chiefhiawa...@gmail.com> wrote in message
>
> news:3148a3d0-ca55-4246...@x69g2000hsx.googlegroups.com...
>
>
>
> > Do you realize how easy it is to calibrate the Powertap, and how
> > little you need to calibrate an SRM?
>
> By all means explain to us how you calibrate a Powertap or an SRM.
>
dumbass,
if you were the brilliant engineer you claim to be you could think for
2 minutes and realize that you can calibate an SRM by hanging known
weights off the crankarm and ensuring that the computer calculates the
expected torque properly.
this would be a grade 10 level project.
the other variable is cadence and the error from each can be
propagated to give the error in the power. we teach this in the first
week of first year physics lab.
b...@mambo.ucolick.org
> <rechungREMOVET...@gmail.com> wrote in message
>
> > The SRM does not need to be sent back routinely for calibration.
>
> And yet two of them will not give you the same answer on the same bike.
Even if I believed you had learned this by experience
with properly calibrated meters, which I don't, you describe
two different problems in metrology.
Problem 1 is a meter whose calibration drifts with time.
This would have to be recalibrated periodically to agree
_with itself_.
Problem 2 is (are) two meters whose readouts disagree.
This doesn't necessarily have anything to do with temporal
drift. If an SRM always gave the same reading, but another
SRM always gave a somewhat different reading, either
might be useful for training purposes as long as you didn't
switch between them. Of course, this implies that the
calibrations are off, and as Amit pointed out, it should be
fairly trivial to test an SRM's calibration by hanging
weights on the crank, unless you're a moonbat on the Moon.
My rule of thumb: Never calibrate anything twice.
Two power meters are worse than one. If you need to
check a calibration, you need three independent
measurements.
Ben
RBR Office of Standards and Practices
Howard Kveck
chiefh...@gmail.com wrote:
He *still* can't tell the difference between 'anonymous' and 'pseudonymous' (and
still thinks that using his own name is a sign of manliness and courage). You post
consistently under this name, so you aren't anonymous.
ila...@gmail.com
> On Dec 3, 3:39 pm, ilan...@gmail.com wrote:>
>
> > even without any other problem, you have to routinely
> > send the SRM back for calibration
>
> This is not true.
>
OK, but I do remember reading at some point that you had to send them
back. Even if that is not necessary, any repair of the SRM will
require an extra set of cranks. On the other hand, a problem with
PowerTap will just involve an extra rear wheel, which I have (as I
suspect most people do). I basically don't have the ability to deal
with potential SRM problems and as I have written about extensively
the local shops in Paris are too horrible for me to deal with.
Other problems with SRM for me was that I live in France and the
distributor seemed awful. It is the bicycle shop Tourmalet, where I
had a previously good experience. However, further dealings with them
were terrible. In particular, the French distributor of SRM did not
have a single crank in stock and was not planning to have any either.
Of course, nothing to do with the actual company, probably more a
reflection of cycling distributors in France.
One good thing about SRM is their manual, which is better written than
most books.
Otherwise, I got my 2nd PowerTap CPU yesterday and installed it, and
it seems that the cadence readings are not consistent with the other
CPU. I will go on a ride tomorrow with both CPU's to see how they
compare. I don't know if that has been done before, research marches
on! While installing it, I also discovered an amazing PowerTap
"feature": The odometer can only be set in miles, that is, if you set
the odometer to 1000 while kilometers are chosen (using a computer,
PowerAgent software and USB cradle) then the CPU will then read
1609!!!
-ilan
ila...@gmail.com
> On Dec 3, 3:39 pm, ilan...@gmail.com wrote:>
>
> > even without any other problem, you have to routinely
> > send the SRM back for calibration
>
> This is not true.
>
> Andy Coggan
Well, I accept your criticism, and am fairly happy with it, because
the lack of any other comment implies that everything else I said was
true.
-ilan
ila...@gmail.com
I bought your Power Meter book. You consistently use the misspelled
term "preme" which should be "prime" from the French word meaning
"bonus", that is, a bonus prize in the middle of a race.
Since I make no other comment, you can assume that I agreed with
everything else in the book and have tried to apply its principles to
my training.
-ilan
Donald Munro
> Forget the wattmeter. Everyone wants to know how you got your wife so
> well calibrated. You could write your own version of "Women are from
> Venus" and retire off the profits.
According to the rbr cosmologist you need 3 points
for calibration so you'll need to get into the swinger
scene.
Or you could try a RGB code but only if your gamma
is right:
http://www.sciencetext.com/compliment-your-partner-with-hex-code.html
rechungR...@gmail.com
> OK, but I do remember reading at some point that you had to send them
> back.
The SRM computer head unit is sealed (and, I understand, it's pretty
cramped in there) so, after several hundred cycles of charge-
discharge, when the rechargeable battery needs replacement it's best
to send it back. There's also a battery in the crank but it's more
accessible so anyone who's halfway handy with a soldering iron can
replace the crank battery himself. For the PT, batteries in both the
head unit and the hub are replaceable by an all-thumbs idiot like me.
BTW, when it's time to change the hub battery, go buy a little tube of
dielectric grease (the stuff they use in cars for spark plug wires) to
coat the gasket with. And I understand that the wireless model eats
batteries faster than mine, though I don't remember offhand if that's
in the hub, the head unit, or both. For me, the head unit battery
lasts maybe a year, the hub longer than that.
Neither the PT nor the SRM need to be routinely sent back for
calibration. You can check the calibration of both a PT and SRM
yourself by flipping them into torque-measuring mode and hanging a
known weight from the crank. You can change the SRM calibration
constant, but not the PT: if the PT is out of spec, you should send it
back for repair.
> One good thing about SRM is their manual, which is better written than
> most books.
Perhaps, but that's because most books are horrible.
> While installing it, I also discovered an amazing PowerTap
> "feature": The odometer can only be set in miles, that is, if you set
> the odometer to 1000 while kilometers are chosen (using a computer,
> PowerAgent software and USB cradle) then the CPU will then read
> 1609!!!
That must be a feature with the PowerAgent software, not the CPU. I
can (and do) enter odometer readings into my CPU in km.
ila...@gmail.com
OK, so I was right about having to routinely send the SRM back (and
thereby requiring extra cranks), I was just wrong about the reason.
I don't know if you noticed, but if you try to set the PowerTap CPU
directly (without using a computer) then it refuses certain readings.
In any case, with my CPU it was impossible to save the value 00014 and
it would save 00019 and so forth. There were only certain readings it
could save. I reported this as a bug to Saris, but without too much
enthusiasm on their part.
-ilan
rechungR...@gmail.com
> OK, so I was right about having to routinely send the SRM back (and
> thereby requiring extra cranks), I was just wrong about the reason.
Well, only if you can't change the crank battery yourself.
> In any case, with my CPU it was impossible to save the value 00014 and
> it would save 00019 and so forth.
Hmmm. I'll have to try that.
SLAVE of THE STATE
> On Dec 7, 6:14 am, ilan...@gmail.com wrote:
>
> > OK, but I do remember reading at some point that you had to send them
> > back.
>
> The SRM computer head unit is sealed (and, I understand, it's pretty
> cramped in there) so, after several hundred cycles of charge-
> discharge, when the rechargeable battery needs replacement it's best
> to send it back. There's also a battery in the crank but it's more
> accessible so anyone who's halfway handy with a soldering iron can
> replace the crank battery himself. For the PT, batteries in both the
> head unit and the hub are replaceable by an all-thumbs idiot like me.
> BTW, when it's time to change the hub battery, go buy a little tube of
> dielectric grease (the stuff they use in cars for spark plug wires) to
> coat the gasket with. And I understand that the wireless model eats
> batteries faster than mine, though I don't remember offhand if that's
> in the hub, the head unit, or both.
One would suspect the transmitter end to need more power, but that is
not guaranteed.
> For me, the head unit battery
> lasts maybe a year, the hub longer than that.
>
> Neither the PT nor the SRM need to be routinely sent back for
> calibration. You can check the calibration of both a PT and SRM
> yourself by flipping them into torque-measuring mode and hanging a
> known weight from the crank. You can change the SRM calibration
> constant, but not the PT: if the PT is out of spec, you should send it
> back for repair.
Or send it to Andy Coggan's wife. She's a primary standard. But even
primary standards need evaluation, for example:
http://tf.nist.gov/general/pdf/1497.pdf
I don't know exactly what Tom's hand in the paper was.
I paid for that paper while you were on your afternoon ride. You are
welcome.
> > One good thing about SRM is their manual, which is better written than
> > most books.
>
> Perhaps, but that's because most books are horrible.
Try reading an ieee paper.
> > While installing it, I also discovered an amazing PowerTap
> > "feature": The odometer can only be set in miles, that is, if you set
> > the odometer to 1000 while kilometers are chosen (using a computer,
> > PowerAgent software and USB cradle) then the CPU will then read
> > 1609!!!
>
> That must be a feature with the PowerAgent software, not the CPU. I
> can (and do) enter odometer readings into my CPU in km.
I reckon it ain't the CPU, as I define a CPU.
Carl Sundquist
"MagillaGorilla" <mag...@sandiegozoo.com> wrote in message
news:fj2qg8$5na$1...@aioe.org...
> chiefh...@gmail.com wrote:
>>>Interpreting power meter data is complex and beyond the scope of most
>>>people, includiing trainers.
>>
>>
>> That's just not true.
>>
>> You just earned yourself an invitation to the powermeter file reading
>> interpretation camp I'm putting on United Center. See you there 7
>> p.m. this Friday.
>>
>
>
> That time you spend discussing power meter data would be better spent
> resting or training.
>
> The most important thing cyclists need to have to improve is motivation
> and happiness. Both of those depend on things like financial stability,
> job happiness, relationship stress, etc. A power meter doesn't even make
> the list.
>
> And to sit here and talk about power meter data in a vacuum as a function
> of traiining comes across as incredibly shallow.
>
> There is NOBODY who works a 9-5 job or goes to college and can honestly
> claim a power meter will help them more than simply training more or
> resting more or being happy more or eating better.
>
> One can accomplish the same thing as a power meter using nothing but timed
> intervals up the same climb. You don't need a $2,500 power meter to
> figure out your fitness.
>
> If you want to micromanage your cycling training to the point where you're
> staring at $2,500 graphs after 6 hour training rides, then you need to
> lighten the fuck up before you turn into a Jeff Evanshine headcase.
>
>
> Magilla
Dude,
Speaking of lightening the fuck up, you probably ought to get off the bike
for a couple of years to gain some perspective. You hold considerable
disdain for the riders who are not competing as a vocation. What you don't
see is that it is a hobby or an escape for them. You see the darker side of
a Walter Mitty-esque scenario, but I don't think the underlying drive is the
same (except for the potential residents of George's future condo
community). And as to the cost of the sport, compare it to many other sports
or recreational activities. What are the material and operating costs for a
boat or golf? Quit thinking like a cheap bastard. It's a quality of life
thing.
P.S. Speaking of flash in the pan juniors, whatever happened to Andrew
Gallatly?
SLAVE of THE STATE
wrote:
> On Dec 5, 9:28 pm, "Tom Kunich" <cyclintom@yahoo. com> wrote:
>
> > <rechungREMOVET...@gmail.com> wrote in message
>
> > > The SRM does not need to be sent back routinely for calibration.
>
> > And yet two of them will not give you the same answer on the same bike.
>
> Even if I believed you had learned this by experience
> with properly calibrated meters, which I don't, you describe
> two different problems in metrology.
>
> Problem 1 is a meter whose calibration drifts with time.
> This would have to be recalibrated periodically to agree
> _with itself_.
All meters drift. No one can measure the "true value."
The NIST t&f motherload paper NIST_TechNote1337.pdf convinced me of
that.
> Problem 2 is (are) two meters whose readouts disagree.
> This doesn't necessarily have anything to do with temporal
> drift. If an SRM always gave the same reading, but another
> SRM always gave a somewhat different reading, either
> might be useful for training purposes as long as you didn't
> switch between them. Of course, this implies that the
> calibrations are off, and as Amit pointed out, it should be
> fairly trivial to test an SRM's calibration by hanging
> weights on the crank, unless you're a moonbat on the Moon.
>
> My rule of thumb: Never calibrate anything twice.
> Two power meters are worse than one. If you need to
> check a calibration, you need three independent
> measurements.
I'm sure you know, but to state it in what I hope is a concise way:
Two meters "agreeing" is actually a statement that the meters have
limited resolution.
Knowing how you love powerpoint and presentations for boneheads (like
me), please see Plate 29:
http://www.freqelec.com/oscillators/osc_overview_4-07.pdf
Donald Munro
Your CPU uses a rotating drum for memory. The nice thing
about those CPU's were that you could hook your indoor
trainer up to them and reduce your carbon footprint. In
your case you could even get your pets to provide power
during their afternoon rides.
Donald Munro
> please see Plate 29:
> http://www.freqelec.com/oscillators/osc_overview_4-07.pdf
They should have used comic sans for the font.
SLAVE of THE STATE
wrote:
> the other variable is cadence and the error from each can be
> propagated to give the error in the power.
I'll guess the "basic" cadence error is easily swamped by the torque
error. Relatively accurate and precise quartz references are cheap.
Do you think the instantaneous angular velocity wavers off enough from
the nominal cadence to cause a "substantial" error? (I don't know.)
I've always wondered how much the angular velocity varies though the
cycle of applied torque.
I spin in perfect circles.
> we teach this in the first
> week of first year physics lab.
lol.
SLAVE of THE STATE
> On Dec 6, 10:05 pm, "amit.gh...@gmail.com" <amit.gh...@gmail.com>
> wrote:
>
> > the other variable is cadence and the error from each can be
> > propagated to give the error in the power.
>
> I'll guess the "basic" cadence error is easily swamped by the torque
> error. Relatively accurate and precise quartz references are cheap.
>
> Do you think the instantaneous angular velocity wavers off enough from
> the nominal cadence to cause a "substantial" error? (I don't know.)
> I've always wondered how much the angular velocity varies though the
> cycle of applied torque.
It just occured to me that despite the good prec/acc of the quartz
itself, the detection of cycles probably has a good bit of phase noise
due to the detector itself, if it is anything like the magnet/coil
arrangement of the cadence meter option to speedometers.