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EuroD
02-23-2011, 10:03 AM
As I've only had these bikes but a couple of weeks, I need some help from those who have experience with Keiser M3s.

Today, one of my riders when he was on a flat road - gear 17, cadence of 100, he found that his watts were at 265. When he was climbing - gear 21, cadence of 50, his watts were 158.

Is this an accurate reflection or are we looking at some wiggle room here.

Vivienne
02-23-2011, 11:13 AM
As I've only had these bikes but a couple of weeks, I need some help from those who have experience with Keiser M3s.

Today, one of my riders when he was on a flat road - gear 17, cadence of 100, he found that his watts were at 265. When he was climbing - gear 21, cadence of 50, his watts were 158.

Is this an accurate reflection or are we looking at some wiggle room here.

Well, Keiser watts aren't Watts such as you'd get from a power meter that uses a strain gauge. Regardless, whether a "K"watt is .75 or 1.25 of a PowerTap Watt, it's consistent and reproducible.....so your rider was actually producing less power at that low grind.

It's an eye opener for the folk who like to load up with resistance and just stand on the pedals to move them.

Vivienne

Funhog
02-23-2011, 12:30 PM
Viv is right.

Now, imagine if he sped his legs up to 60 or even 70 on that grind! That would be GREAT power output. But what if that is not sustainable, that his HR soars too high and he becomes breathless? Fine for a quick surge (20-60 seconds) up a short hill, but what if it is a long hill? Maybe he has to drop down to gear 20 or 19 to maintain that, but even though power drops a little when he does so, he can go a long time, ultimately leading to a greater average power output (and higher average caloric consumption). Well then that is that lightbulb moment when he realizes it's better to ride above 60rpm at a sustainable gear, and save the knees and not fatigue the muscles so much.

Vivienne
02-23-2011, 12:53 PM
Adding to what Jen said.....

For how I do my classes.....not every class is all about maximum power output all the time. So, my muscle endurance, muscle overload "strength" rides are sometimes about just finding that resistance (whatever "gear" it happens to be for each individual) that provides the appropriate challenge for however long and however hard I happen to be "writing the presciption".....and I should add that these "prescriptions" are no more mine than one for PenVK might be. I tend to use evidence-based, training rationales for the stuff I teach in class.

One of the things I now have to do with my Keiser Athletes-In-Training is to get them to wean themselves away from working to "the numbers". I'm trying to get them to retain enough of what was RPE and relate it to maybe either cadence, "wattage" or "gear".......but to also show a bit of gumption and not beat themselves up trying to master all three.

Vivienne

Megale
02-23-2011, 01:12 PM
Not really big on using gears in class. But there are three ways to create more power/watts. This helps when you run out of gears LOL:D

1) Add resistance keeping the same cadence (as long as the lever has more throw left)

2) Speeding up your cadence with the same resistance (really helps after the lever is at the end of its throw:cool: )

3) Speed up your cadence while adding resistance :eek:(see varies above)

All things being the same -movement in and out of the saddle will be one of leverage , energy consumption/retention and sustainability.

Have fun on the bikes
Mike

Vivienne
02-23-2011, 01:36 PM
Today, one of my riders when he was on a flat road - gear 17, cadence of 100, he found that his watts were at 265. When he was climbing - gear 21, cadence of 50, his watts were 158.



While I'm thinking about it....

Was this "flat road-gear 17, cadence 100 rpm" something that he'd sustained or could sustain for a significant amount of time without issue (I'd be thinking of, say, 20 minutes or more)

I only ask because just an addition of a few "gears" took him to something that needed a cadence of 50 rpm to hack ("hack" being a long way from "sustain")

I really wish our Emeritus IDC Instructor, AC in NJ would come out of premature retirement and clarify how us newbies-to-power should interpret what we're observing.

Vivienne

Funhog
02-23-2011, 02:35 PM
While I'm thinking about it....

Was this "flat road-gear 17, cadence 100 rpm" something that he'd sustained or could sustain for a significant amount of time without issue (I'd be thinking of, say, 20 minutes or more)

I only ask because just an addition of a few "gears" took him to something that needed a cadence of 50 rpm to hack ("hack" being a long way from "sustain")

Vivienne

I was going to ask the same thing. It also seems to me that 100 rpm in gear 17 seems quite high. I'm on the high teens like that on our Keisers when on a climb. I could see a sprint at 100rpm in gear 17....but not sustainable output unless he truly is a powerhouse.

Megale
02-23-2011, 03:46 PM
I was going to ask the same thing. It also seems to me that 100 rpm in gear 17 seems quite high. I'm on the high teens like that on our Keisers when on a climb. I could see a sprint at 100rpm in gear 17....but not sustainable output unless he truly is a powerhouse.
Just needs to be a larger guy that is use to his body weight till he hits a hill and has to carry it.
Mike

Vivienne
02-23-2011, 04:06 PM
Just needs to be a larger guy that is use to his body weight till he hits a hill and has to carry it.
Mike

There's a limit to how much effect bodyweight has when you're sitting on a stationary bike.

Vivienne

Funhog
02-23-2011, 04:25 PM
Just needs to be a larger guy that is use to his body weight till he hits a hill and has to carry it.
Mike

Still that's a pretty high gear for anyone to maintain 100rpm unless he was pushing it very hard for very short amount of time.

Indoors we're not worried about that hill (and the effect of gravity/bodyweight), but you're right, if he is a larger guy he's a better hill climber indoors than out!

Megale
02-23-2011, 05:54 PM
Still that's a pretty high gear for anyone to maintain 100rpm unless he was pushing it very hard for very short amount of time.

Indoors we're not worried about that hill (and the effect of gravity/bodyweight), but you're right, if he is a larger guy he's a better hill climber indoors than out!

I see a Lance Vs Jan comparison contrast comin :)
M

tking
02-23-2011, 09:28 PM
Well, Keiser watts aren't Watts such as you'd get from a power meter that uses a strain gauge. Regardless, whether a "K"watt is .75 or 1.25 of a PowerTap Watt, it's consistent and reproducible.....so your rider was actually producing less power at that low grind.

It's an eye opener for the folk who like to load up with resistance and just stand on the pedals to move them.

Vivienne

One of our athletes has a Felt Tri-Bike with a Cycleops Powertap rear hub. It’s a fact that the Powertap is used worldwide and is a “must have” device for competitive cyclists training with power. We calibrated our M3s using the Felt/Powertap as the standard. Our athlete brought in his Felt Tri-Bike and his Kinetic Trainer. For the test we set-up his Felt and a M3 side-by-side and then he proceeded to ride his Felt at a given watts and RPM and rode the M3 at the same watts and RPM all the while comparing “pedal feel” on each bike. We went back and forth adjusting the M3 until the pedal feel on the M3 was the same as the pedal feel on the Felt, again, at the same watts and RPM. We then calibrated all the other M3s to have the same pedal feel as the "master" M3. We now feel that the watts displayed on our M3s are very representative of a "real" bike.

matteobma
02-24-2011, 03:09 AM
...For the test we set-up his Felt and a M3 side-by-side and then he proceeded to ride his Felt at a given watts and RPM and rode the M3 at the same watts and RPM all the while comparing “pedal feel” on each bike. ...We now feel that the watts displayed on our M3s are very representative of a "real" bike.

It is a nice intention and idea to reduce measure errors and have the same bike brake setting.
Unfortunately,(IMO) it's like trying to adjust the speedometer bicycle comparing the "speed feeling" as that one of driving car.

Ciao Matteo :)

Dellphinus
02-24-2011, 06:59 AM
100 at 17 and was showing 265 "watts" seems odd to me. I use an M3 for training, and during 30/30 intervals, 90-95 rpm at 18 produces ~480-500 "watts". Can't do it for more than 30 seconds.

During form intervals, 85 rpm at 16 produces 330 "watts".

Could it be that our bikes, or your bikes, need calibration? Or could it have been calories your guy was seeing? Or is there just that much variation between M3s (all 4 of ours read the same for same settings though, but they're also all only a month old)?

Curious...

Vivienne
02-24-2011, 08:40 AM
100 at 17 and was showing 265 "watts" seems odd to me

Well, the reason why I'm smelling fish isn't so much the purported wattage but the notion that a resistance change from "17" to "21" could alter the ability to handle a cadence of 100rpm to a need to grind away a 50 rpm within such a short range of resistance (I'm assuming that a 50 rpm really is based on need rather than choice).....those two cadences are both so far out of my personal comfort zone that they represent a really big difference

Assuming someone's sitting on the same bike throughout this transition, I fancy that there would have to be something wrong with that bike to account for this disproportionate increase in load. Assuming, of course that the 100rpm thang wasn't just a 30 second or less flash in the pan.......or that there was accurate reporting of those readings.

Vivienne

Todd S
02-24-2011, 10:00 AM
It is a nice intention and idea to reduce measure errors and have the same bike brake setting.
Unfortunately,(IMO) it's like trying to adjust the speedometer bicycle comparing the "speed feeling" as that one of driving car.

Ciao Matteo :)

+1

I agree. But it sounds like it's the best he can do.

matteobma
02-24-2011, 10:30 AM
More on ergometer calibration:
http://www.vacumed.com/292.html

an (old but still actual) tool developped for ergometer:
http://www.vacumed.com/zcom/product/Product.do?compid=27&prodid=323

Ciao Matteo :)

Todd S
02-24-2011, 12:38 PM
More on ergometer calibration:
http://www.vacumed.com/292.html

an (old but still actual) tool developped for ergometer:
http://www.vacumed.com/zcom/product/Product.do?compid=27&prodid=323

Ciao Matteo :)

If the world were perfect clubs would spend $18000 on a calibrating machine for their bikes.

Problem is, it's not. But on these bikes if power output is proportional to the Eddy current produced, one may be able to calibrate the bikes with a simple voltage or current meter. (Not sure, but I'm assuming that these bikes produce resistance by running the Eddy current produced across a resistor. http://en.wikipedia.org/wiki/Eddy_current_brake )

Dellphinus
02-24-2011, 02:07 PM
If the world were perfect clubs would spend $18000 on a calibrating machine for their bikes.

Problem is, it's not. But on these bikes if power output is proportional to the Eddy current produced, one may be able to calibrate the bikes with a simple voltage or current meter. (Not sure, but I'm assuming that these bikes produce resistance by running the Eddy current produced across a resistor. http://en.wikipedia.org/wiki/Eddy_current_brake )

If I'm reading the Keiser site right, and I am remembering all those classes right...

The disc, rotating between the magnets, generates eddy currents within the disc itself. These eddy currents in turn generate a magnetic field around the disc that interacts with the bike magnets to create the resistance. There's no real way to measure the eddy currents.

The lever moving causes more and more magnet to be overlapped on the disc, creating more and more current and hence resistance. The lever also causes a potentiometer (like a volume control) to change as it rotates more magnet into/out of the disc. The computer reads the potentiometer and uses the value it sees, and the cadence, to "look up" the power (watts) in a table. The table was created by Keiser by testing against a real ergometer. So no, it doesn't actually measure power. But if the potentiometer and magnet assembly are calibrated to each other (same rotation on each), and the magnets are spaced properly from the wheel, then it should be relatively repeatable, and as accurate as the lookup table.

The calibration procedure- 5 times full on to full off on the lever- I think this is how the computer determines what the minimum and maximum values it'll see from the potentiometer, and correct for changes/misalignments. It has to assume that the magnets are rotated full off, and full on at each end of lever travel, and it matches the potentiometer readings to that during the calibration.

I think...

Only way to actually measure power on one would be to measure the torque in the crank arms, in the belt, at the magnet assembly or at the axle... all pretty hard and/or expensive...

Sorry if this was more info than needed/wanted, I got on a roll...

Todd S
02-24-2011, 02:58 PM
Thanks. I was trying to picture how they would work having never actually seen and touched one yet.

matteobma
02-25-2011, 05:07 AM
If the world were perfect clubs would spend $18000 on a calibrating machine for their bikes.
$$$$ :eek::eek::eek: ...I have NOW seen the tool price ! :o

Ciao Matteo:)

tking
02-25-2011, 11:59 AM
More on ergometer calibration:
http://www.vacumed.com/292.html

an (old but still actual) tool developped for ergometer:
http://www.vacumed.com/zcom/product/Product.do?compid=27&prodid=323

Ciao Matteo :)

Hi Matteo

Thanks for the excellent reference to Vacumed.com and their Ergometer Calibrator. Do you have experience using this device or a device like it? How did it go?

I called Vacumed, talked with Dr. Andrew Huszczuk, and learned the following:


The purchase price of an Ergometer Calibrator is approximately US$18,000.
About 12 years ago they rented a unit but it came back trashed so they don’t rent anymore.
About the same time a facility shipped a bike to Vacumed for calibration but when the bike got back to the owner it was damaged in shipment so they don’t take bikes in for calibration anymore.
Their device is used primarily on Monark and Lode stationary bikes, bikes that you might find in a place that does lots of physical therapy or in facilities that do high-end professional/collegiate athletic training.
Dr. Huszczuk had not heard of Keiser. He checked out the Keiser web site and replied that yes, they could adapt their Ergometer Calibrator to do a power calibration on an M3.

Where this all stands with me is that I’m trying to find a service provider in the upper Midwest that could travel to Duluth and calibrate our bikes although my guess right now is that the price tag will be way out of our league.

I feel pretty good that doing a side-by-side calibration check using a road bike with a PowerTap rear hub on a trainer then compared to an M3 is an OK method for adjusting the pedal feel of an M3. It’s the best method I have come up with so far that’s relatively easy to do and doesn’t cost anything. And, besides, our members, primarily the competitive cyclists, are very pleased with the results.

About 6 months ago I tried a calibration check very similar to the Vacumed device. At the time I was trying to find a quantifiable method for making our M3s each have the same pedal feel, I wasn’t trying to validate the watt value. I took an 8-amp, high torque, low RPM, electric drill fitted with a square nut driver. I removed the crank arm from an M3 and then “drove” the bike using the electric drill. While the drill was working I measured the amps going into the drill motor. To make a long story short, it didn’t work. My set-up wasn’t robust enough to handle the torque and the drill overheated trying to run at 90 RPM with the applied load. It was kind of like trying to pin a grizzly bear on the floor while at the same time trying to insert and read a rectal thermometer. Uff Da!

EuroD
02-25-2011, 12:54 PM
Nice to know I can stir up some interesting conversation.

OK - so let me answer some of the things mentioned.

Firstly, it was not a 30 second blast. We were on a flat for approximately 6 minutes. Climbs were between 5-9 minutes.

The rider in question is slim, rides alot outside, and not known for an aggressive cadence - doesn't go over 100rpm as he feels out of control; yeah someone who gets it.

He was not looking at the caloric expenditure number but the 'watts'. I explain to each class I teach what each of the numbers means, and make it very clear that they should not mistake the flip between kcals and watts as they ride. I suggest to them that if they want to know their average watts that they stop the peddles (dead stop, as Jennifer says OUCH) and see the average output.

It IS possible that particular bike had poor calibration so I cannot answer to that particular issue. Even being new bikes, I know that the calibration can drop off, or that it was not done effectively from the get go. I am not sure who set them up in the first place, and as I am the only one obsessing over this at my place, I'm not going to start rocking the boat until I can provide proof if something is off.

I have to run a test for myself to see whether I experience anything similar as I cannot do it when teaching.

It still sounds 'odd' to me, and I will have him drop a couple of gears and increase the pace to see what shakes out.

I truly appreciate all your thoughts on this subject.

Dellphinus
02-25-2011, 02:26 PM
...
About 6 months ago I tried a calibration check very similar to the Vacumed device. At the time I was trying to find a quantifiable method for making our M3s each have the same pedal feel, I wasn’t trying to validate the watt value. I took an 8-amp, high torque, low RPM, electric drill fitted with a square nut driver. I removed the crank arm from an M3 and then “drove” the bike using the electric drill. While the drill was working I measured the amps going into the drill motor. To make a long story short, it didn’t work. My set-up wasn’t robust enough to handle the torque and the drill overheated trying to run at 90 RPM with the applied load. It was kind of like trying to pin a grizzly bear on the floor while at the same time trying to insert and read a rectal thermometer. Uff Da!

That was a nice attempt!

A thought, since it sounds like you're REALLY interested in quantifying this.
If you could get a suitable scale- hanging type, hook on each end, hook it around the pedal axle, and measure the force required to keep the pedal rotating for a quarter turn or so... force, crank length gives torque; torque, RPM give power... Once you know the torque you can calc power at any RPM.
Don't know what kind of accuracy it'd yield; short duration, angle of pull relative to axle, etc. just a thought.
EDIT: Eh.. this won't work... need some minimal speed to induce the currents...


I've asked Keiser if they could provide "check" values- x RPM at Y gear setting should produce Z+- watts on the display, as a way to determine if calibration or service is needed. No response yet...

matteobma
02-28-2011, 04:45 AM
Hi Matteo
... Do you have experience using this device or a device like it? How did it go?
6 years ago, I had tried to join a road bike equipped with power tap (power measure unit) and an indoor bike, with a little frame that joint the rear wheel (of road bike) with the indoor bike wheel.
My idea was that using the brake wheel (on indoor bike) I can measure the power supplied on road bike and define some marker on brake resistance knobs.
The result was like your "grizzly bear ...& rectal thermometer".:D:cool:

The next step it was to equip the indoor bike with an (used) srm power meter... http://www.srm.de/index.php?lang=en

The IC bike has assumed an ergometer look !:p (...and cost).

Ciao Matteo :)

thojj
10-29-2011, 09:26 AM
100 at 17 and was showing 265 "watts" seems odd to me. I use an M3 for training, and during 30/30 intervals, 90-95 rpm at 18 produces ~480-500 "watts". Can't do it for more than 30 seconds.

During form intervals, 85 rpm at 16 produces 330 "watts".

Could it be that our bikes, or your bikes, need calibration? Or could it have been calories your guy was seeing? Or is there just that much variation between M3s (all 4 of ours read the same for same settings though, but they're also all only a month old)?

Curious...

Gear 14 @100 rpm = 301 watts. on each of our 25 M3 bikes this very morning,much to the amusement of a full class!

Funhog
10-29-2011, 10:53 AM
Gear 14 @100 rpm = 301 watts. on each of our 25 M3 bikes this very morning,much to the amusement of a full class!

Are the bikes new? Recently calibrated? Each of your 25 students could generate 301 watts?
At one club where I teach, I have a few smaller female students who are older but still pretty fit, who could not generate 300 watts if they tried (oh maybe a sprint, but only for a few seconds, and probably not at 100rpm). Maybe all 25 of your students are younger and stronger.

Delphinius' question about whether Keiser could provide a chart of wattage at each cadence and gear when calibrated correctly is a good one. I can't imagine why they wouldn't make that available.

thojj
11-02-2011, 10:35 PM
Average class I assume,mixture of young,old,female and male.The amusement was that when asked to perform 100 watts for a short period of time mid session everyone produced even those who had previously not ventured into the teen gears.Maybe having suggested what I was trying to note might have just taken theI cant" and changed it to a " I can" purely for the experiment.This does not detract from basic fact being that 100 rpm @ speed 17 should show way more watts than suggested.

liveon2wheels
11-03-2011, 08:29 AM
I've resisted the urge to weigh in because this topic is in many ways a bit futile, and ultimately frustrating in many ways. As I see it, to get the "straight poop" on the watts of ANY bike producing CALCULATED power, we need to wait till one of the two Pedal Deployed power meters come out. Both Metrigear (now owned by Garmin) (http://velonews.competitor.com/2011/08/bikes-and-tech/quick-look-garmin-vector-power-meter_188454) originally for the speedplay style pedal but now possibly for KEO style instead, and Polar for the Look/KEO style pedal (http://www.bicycling.com/bikes-gear/2011-bike-and-gear-previews/look-keo-power-pedals).

Once we can get our hands on one of these, we should be able to mount it on any indoor bike much like it's designed for the outdoor bike, and get some true measured power readings. Until that time... we are at best filling the air with lots of speculative pontifications... which in some cases, just makes it harder to breath while we are trying to climb that huge hill in front of us. :)

Todd S
11-03-2011, 10:07 AM
Too bad at this point they're still only vaporware.

tking
11-03-2011, 12:00 PM
Are the bikes new? Recently calibrated? Each of your 25 students could generate 301 watts?
At one club where I teach, I have a few smaller female students who are older but still pretty fit, who could not generate 300 watts if they tried (oh maybe a sprint, but only for a few seconds, and probably not at 100rpm). Maybe all 25 of your students are younger and stronger.

Delphinius' question about whether Keiser could provide a chart of wattage at each cadence and gear when calibrated correctly is a good one. I can't imagine why they wouldn't make that available.

Fun discussion!

I checked a 2007 and a 2009 model of our M3s and at 100 RPM and gear 14 they both display 300 watts. This agrees with thojj’s findings. This doesn’t surprise me because watts is calculated based on the gear and cadence the bike is in, it has nothing to do with the work the person is doing. I suspect that M3’s all over the world will display 300 watts at gear 14 and 100 RPM.

However, the variable we can’t account for very well is what I call “pedal feel”. That is a bike can be adjusted to pedal hard or easy. Gino hit it right on the head that we need the new style pedals that measure work (watts). Then we will get an actual measure of work opposed to a calculated measure. In the meantime, the M3s can be calibrated, to a degree, if you have the need.


When it comes to calibrating a M3 there are several levels of need that may arise. If the M3s are used for regular “spin” classes then in my opinion there is no need to calibrate the bikes at all. In this environment the instructor should be using perceived level of exertion. In a “power” class an athlete will want to measure and chart their performance (watts). If you have the athlete ride the same bike each time then the results will be pertinent to that individual. At this level you should not make person-to-person comparisons because each bike may have different “pedal feel”

The next level is suppose you want each bike in your studio to have the same pedal feel so that an athlete can ride any bike and have the same experience. This also allows you to make athlete-to-athlete comparisons.

Pedal feel is a function of the position of the magnet assembly at rest. When the magnet assembly is far away from the center of the flywheel then the bike will pedal “easy”. As the magnet assembly moves towards the center of the flywheel it gets progressively more difficult to pedal. Just in front of the magnet assembly is a barrel adjustment for shift cable length. You can actually adjust the magnet assembly position at rest by using the barrel adjustment.

So let’s go back to the level where you want each bike to have the same pedal feel. You do this by selecting a “master” bike then riding each of the other bikes and adjusting each one to match the master. Yes, this is a very subjective exercise. The best way to do this is to have several athletes check each bike for easy/hard and look for results where all agree that a particular bike is easier/harder than the master.

The next level is say you want to compare your results to bikes outside your studio. To do this you need some sort of calibration standard. Right or wrong we did the following with very good user reviews. We brought in a Felt Tri-Bike fitted with a PowerTap rear hub and a resistance trainer. We rode the Felt at, say, 90 RPM and 300 watts and then rode the M3 at 90 RPM and 300 watts. We checked to see if 300 watts on the M3 had the same pedal feel as the Felt at 300 watts. We adjusted the M3 until the M3 had the same pedal feel as the Felt. The M3 that we used to test was then declared the “master” and then we adjusted all the other Keisers to match the master.

So now we have all of our M3s calibrated to a standard of sorts. In our studio our athletes can ride any bike and have the same experience. We can make athlete-to-athlete comparisons and for a given athlete, year-to-year comparisons. When we calculate an athlete’s Power to Weight Ratio we have a degree of confidence that the result is approximately equal to published ratios for other athletes.

Per Delphinius' comment I went crazy and generated some graphs for discussion, see attached.

The graph “Watts vs. Cadence” is interesting in that in gear 7, from 80 to 100 RPM, watts increases from 80 to 100 watts, an increase of 10 watts for an increase of 10 RPM. You can also note that gear 7 is what I call the “magical” gear, that is at gear 7 the cadence and watts will always be equal. Note that in gear 13, from 80 to 100 RPM, watts increases from 200 to 263 watts, an increase of 31.5 watts for an increase of 10 RPM.

The graph “Watts vs. Gear” shows my actual test results for riding each gear (up to 20) at 90 RPM and recording watts. I suspect with a bunch of data points the “average” plot will come out to be a straight line.

Thanks

thojj
12-14-2011, 09:59 AM
Further to this entry my new PB is 104/405 over 30 minutes which is laying in gear 16 at over 110rpm.confirming original quote from Dellphinus.This morning the new PB for 20 minutes was 102/430.This is the last full blooded run this year as there are only 5 spin class's left for me upto xmas and Im going to just be *spinning*not racing.By the way Im male 54 and 28 months down the road from commited smoker and over 20 stone,now non smoker and 13 stone so I think*average*is probably about right for me anyway.Just for the record my training*sister*,who is 50 kg,regularly averages over 300 watts.

Dellphinus
12-19-2011, 08:12 AM
Never did receive a response from Keiser on the calibration data, but...
In retrospect, it wouldn't work. Say Keiser gives us a table that says 90 RPM in gear 16 should show 250 watts. All that'd do is calibrate the potentiometer position (in effect what the 5 on/off cycle does). There's no way, without using some form of power measuring device, to calibrate the actual power reading. Best that could be done is to measure/set the gap between the magnets and the disk, and the rotational point where the magnets overlap the disk. Even that would not take into account variations in magnet strength.

Another question- does anyone know if the M3 calorie reading is just a straight conversion from watts, or does it factor in other metabolic constants/values/voodoo magic? I.E. does 1-hr at 190 W avg show 164 Cal? Or does it factor in efficiency (say 25%) and show say 656 Cal? Have to check tonight...

Vivienne
12-19-2011, 08:33 AM
ANother question- does anyone know if the M3 calorie reading is just a straight conversion from watts, or does it factor in other metabloic contstnats/values/voodoo magic? I.E. does 1-hr at 190 W avg show 164 cal? Or does it factor in efficiency (say 25%) and show say 656 cal? HAve to check tonight...

I'm going to go for something close to the voodoo magic thing.......since it's as close to the chocolate chip cookie consumption parameter as anything else.

Given that Keiser Watts aren't James Watts (*AS ADVERTISED* in your high school physics class) it doesn't matter the conversion factors or constants or whatnot......you won't be much closer than a crumb or 20 than guesstimating.

Vivienne