New power meter...pleas help me understand
#1
New power meter...pleas help me understand
So I am only a few months into road cycling and just got a power meter. I’ve been using a Peloton indoors for a year or so now, so I have a rough idea where I should (think) be power wise. On a 45 minute Peloton ride I average roughly 260 watts +/-. On my first few rides with a 4iiii left crank power meter I am averaging 190-210 watts for roughly 30 mile rides depending on which device you take the readings from (Wahoo, Strava, Ride w/ GPS...not sure why they differ). Normalized power which my guess is a better comparison? Is around 220 watts. Obviously I am doing longer rides outdoors as I average 20mph most rides so almost twice as long in duration. I kind of doubt that explains the whole difference in power though assuming devices are calibrated similarly.
There could obviously be calibration differences, but I don’t think those are likely to be more than a few percentage points. Not a big deal, but just generally curious by the magnitude of the difference. Anyone else have similar experiences? Or any advice on how to interpret the various power metrics.
There could obviously be calibration differences, but I don’t think those are likely to be more than a few percentage points. Not a big deal, but just generally curious by the magnitude of the difference. Anyone else have similar experiences? Or any advice on how to interpret the various power metrics.
#2
Non omnino gravis
My guess would be that the Peleton shows a bigger number because bigger power numbers make people feel better. The 4iiii doesn't care about your feelings.
You've also got "new power meter fever" out on the road, so I wouldn't put too much thought into those numbers. Give it a couple of months.
You've also got "new power meter fever" out on the road, so I wouldn't put too much thought into those numbers. Give it a couple of months.
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#3
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Peleton bikes don't have an actual power meter... they estimate power using flywheel rotational speed and resistance (thus the huge variability that even Peleton admits to). And as DrIsotope says, they're incentivized to err on the upside of power output.
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There could obviously be calibration differences, but I don’t think those are likely to be more than a few percentage points. Not a big deal, but just generally curious by the magnitude of the difference. Anyone else have similar experiences? Or any advice on how to interpret the various power metrics.
How much time are you coasting and riding Z1 watts? I bet it's way more than you realize. Super not uncommon to have rides with 30% + coasting or soft-pedaling until you make a point not to do that.
And when you do, average power goes way up, and speed probably does too.
If the route makes it possible, I'd shoot for <10% Z1. That ensures you're putting power to the pedals at all times save turns, stops, or too steep/technical downhills.
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#6
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1) I imagine that pedaling in a class, even a virtual one, is more motivating than just riding around. Do you have a heart rate monitor? How does your HR compare?
2) How is the bike software handling “0” in the power reading? The number can be lower if zeros are included, however the normalized power should be close to a steady effort ignoring any zeros from the power meter.
3) Totally disagree with the power doesn’t matter comment, it’s really the only way to compare your on bike performance. There are too many variables for speed (wind, temperature, road surface, riding in a group or not, etc etc), but power is your real output and what you should be comparing between workouts.
4) I really wouldn’t worry too much about the Peloton vs power meter difference. On the Peloton you work on improving your PR Peloton numbers, and on the bike work to improve your bike PR numbers and fitness and eventually you’ll workout what the offset is and if you care.
2) How is the bike software handling “0” in the power reading? The number can be lower if zeros are included, however the normalized power should be close to a steady effort ignoring any zeros from the power meter.
3) Totally disagree with the power doesn’t matter comment, it’s really the only way to compare your on bike performance. There are too many variables for speed (wind, temperature, road surface, riding in a group or not, etc etc), but power is your real output and what you should be comparing between workouts.
4) I really wouldn’t worry too much about the Peloton vs power meter difference. On the Peloton you work on improving your PR Peloton numbers, and on the bike work to improve your bike PR numbers and fitness and eventually you’ll workout what the offset is and if you care.
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#7
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Some may only look at power while moving, so if you stop at a light it's not a period of zero power, and some may ignore power while coasting or below some small threshold.
Also, uphills kill your average speed, downhills kill your average power.
Also, uphills kill your average speed, downhills kill your average power.
#8
1) I imagine that pedaling in a class, even a virtual one, is more motivating than just riding around. Do you have a heart rate monitor? How does your HR compare?
2) How is the bike software handling “0” in the power reading? The number can be lower if zeros are included, however the normalized power should be close to a steady effort ignoring any zeros from the power meter.
3) Totally disagree with the power doesn’t matter comment, it’s really the only way to compare your on bike performance. There are too many variables for speed (wind, temperature, road surface, riding in a group or not, etc etc), but power is your real output and what you should be comparing between workouts.
4) I really wouldn’t worry too much about the Peloton vs power meter difference. On the Peloton you work on improving your PR Peloton numbers, and on the bike work to improve your bike PR numbers and fitness and eventually you’ll workout what the offset is and if you care.
2) How is the bike software handling “0” in the power reading? The number can be lower if zeros are included, however the normalized power should be close to a steady effort ignoring any zeros from the power meter.
3) Totally disagree with the power doesn’t matter comment, it’s really the only way to compare your on bike performance. There are too many variables for speed (wind, temperature, road surface, riding in a group or not, etc etc), but power is your real output and what you should be comparing between workouts.
4) I really wouldn’t worry too much about the Peloton vs power meter difference. On the Peloton you work on improving your PR Peloton numbers, and on the bike work to improve your bike PR numbers and fitness and eventually you’ll workout what the offset is and if you care.
Fair point on number 4...I guess I just assumed they would be a bit closer. And I totally get the inconsistency in Peloton numbers, but disagree with the inflated numbers to make people feel good comment. There are definitely plenty of people who juice their bike just for metrics though.
#9
Senior Member
One other thought: if you're interested in tracking your power output progress, the actual power level you're putting out is less important than the relative change in power output over time. You want a power meter that is consistent in measurement so that you can see how the metrics change over time. This is why many experts say the accuracy of a given power meter is less important than the consistency of a given power meter.
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#10
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*Though I heard this attributed to Feynman, it's origin is much older than that probably dating to around 1781 by Martin Sherlock
Last edited by asgelle; 08-30-20 at 02:49 PM.
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I have a Peloton bike also, and there are known problems with power measurements. As mentioned above, Peloton does not use an actual power meter. Instead, it calculates power based on resistance and cadence. In theory, this should work correctly. However, it only works correctly if the resistance is calibrated correctly. The Peloton bike uses magnets to create resistance. The closer the magnets are to the flywheel, the more resistance. The problem is that 50% resistance on your bike and 50% resistance on my bike may not be the same. And, in fact, they probably aren't. If you look at the top of the leaderboards for any ride, you'll see people putting out ridiculous power numbers. That's because their bikes aren't calibrated. I've seen people riding entire classes at 100% resistance. On my bike, even peak Lance couldn't do that. I'm told that Peloton recalibrates the bikes in their live studios every week.
I don't know your athletic background, but if you've only been riding a short time, I'd be incredibly surprised if you could sustain 260 watts. I'm almost positive your Peloton bike is out of calibration. Your 4iiii numbers seem much more reasonable.
In order to get a somewhat accurate power reading on the Peloton, you need to go through a calibration procedure. If you google it, you will find instructional videos. If you contact Peloton, they will send you a calibration kit for free. I got one but I haven't done it yet because it is somewhat complicated and temperamental and because I think my Peloton is actually pretty accurate when I compare it to my road bike numbers. One of these days, I will put my Favero Assioma pedals on my Peloton bike and compare outputs (maybe even tonight if I'm feeling motivated).
I don't know your athletic background, but if you've only been riding a short time, I'd be incredibly surprised if you could sustain 260 watts. I'm almost positive your Peloton bike is out of calibration. Your 4iiii numbers seem much more reasonable.
In order to get a somewhat accurate power reading on the Peloton, you need to go through a calibration procedure. If you google it, you will find instructional videos. If you contact Peloton, they will send you a calibration kit for free. I got one but I haven't done it yet because it is somewhat complicated and temperamental and because I think my Peloton is actually pretty accurate when I compare it to my road bike numbers. One of these days, I will put my Favero Assioma pedals on my Peloton bike and compare outputs (maybe even tonight if I'm feeling motivated).
#13
I have a Peloton bike also, and there are known problems with power measurements. As mentioned above, Peloton does not use an actual power meter. Instead, it calculates power based on resistance and cadence. In theory, this should work correctly. However, it only works correctly if the resistance is calibrated correctly. The Peloton bike uses magnets to create resistance. The closer the magnets are to the flywheel, the more resistance. The problem is that 50% resistance on your bike and 50% resistance on my bike may not be the same. And, in fact, they probably aren't. If you look at the top of the leaderboards for any ride, you'll see people putting out ridiculous power numbers. That's because their bikes aren't calibrated. I've seen people riding entire classes at 100% resistance. On my bike, even peak Lance couldn't do that. I'm told that Peloton recalibrates the bikes in their live studios every week.
I don't know your athletic background, but if you've only been riding a short time, I'd be incredibly surprised if you could sustain 260 watts. I'm almost positive your Peloton bike is out of calibration. Your 4iiii numbers seem much more reasonable.
In order to get a somewhat accurate power reading on the Peloton, you need to go through a calibration procedure. If you google it, you will find instructional videos. If you contact Peloton, they will send you a calibration kit for free. I got one but I haven't done it yet because it is somewhat complicated and temperamental and because I think my Peloton is actually pretty accurate when I compare it to my road bike numbers. One of these days, I will put my Favero Assioma pedals on my Peloton bike and compare outputs (maybe even tonight if I'm feeling motivated).
I don't know your athletic background, but if you've only been riding a short time, I'd be incredibly surprised if you could sustain 260 watts. I'm almost positive your Peloton bike is out of calibration. Your 4iiii numbers seem much more reasonable.
In order to get a somewhat accurate power reading on the Peloton, you need to go through a calibration procedure. If you google it, you will find instructional videos. If you contact Peloton, they will send you a calibration kit for free. I got one but I haven't done it yet because it is somewhat complicated and temperamental and because I think my Peloton is actually pretty accurate when I compare it to my road bike numbers. One of these days, I will put my Favero Assioma pedals on my Peloton bike and compare outputs (maybe even tonight if I'm feeling motivated).
#14
Newbie racer
205w AP over 50ft per mile nets about 20mph.
Rubi and myself both have meters and seem to get similar data for that pace.
260w? You would be well over 20.
The data says the peloton reads high. Really high. 50w out of 260 is a lot.
Rubi and myself both have meters and seem to get similar data for that pace.
260w? You would be well over 20.
The data says the peloton reads high. Really high. 50w out of 260 is a lot.
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One of the guys in my club sent me a screen grab of his friend's Peloton ride. Guy was BEASTIN' with average power just under 300w! Unfortunately, my friend, who has an FTP in the low 200s, said that he can drop him like a rock IRL - he thought it was pretty funny.
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OK - I just finished my experiment. I mounted my Favero Assioma Duo power meter pedals on my Peloton bike and ran the zero calibration routine in the app. I did a 60-minute "Power Zone Endurance Ride," which was a long warm-up, followed by four 9-minute Zone 3 intervals, with Zone 2 breaks in between (i.e., it's a very steady, moderate workout).
According to Peloton, I averaged 158 watts, with a total output of 568 kJ.
According to the Faveros (using the Cyclemeter app on my iPhone), I averaged 175 watts with a total output of 632 kJ.
So, in my case, the Peloton was too too low by approximately 10%. I will attempt to use the Peloton calibration kit one of these days and see if I can get the Peloton more in line with my pedals, and then I will have to retake my FTP test.
[By the way, I used my Apple Watch to monitor my HR for Cyclemeter, and a Scoshe Rhythm 24 armband to monitor my HR for Peloton. They were virtually identical the entire ride.]
Call me DC Rainmaker Jr.
According to Peloton, I averaged 158 watts, with a total output of 568 kJ.
According to the Faveros (using the Cyclemeter app on my iPhone), I averaged 175 watts with a total output of 632 kJ.
So, in my case, the Peloton was too too low by approximately 10%. I will attempt to use the Peloton calibration kit one of these days and see if I can get the Peloton more in line with my pedals, and then I will have to retake my FTP test.
[By the way, I used my Apple Watch to monitor my HR for Cyclemeter, and a Scoshe Rhythm 24 armband to monitor my HR for Peloton. They were virtually identical the entire ride.]
Call me DC Rainmaker Jr.
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I basically stopped looking at the leaderboard. It's a joke. Other than that, I actually do really like the Peloton. The whole family can use it, and I also take advantage of the strength, stretching and yoga classes.
#18
Senior Member
If a number of these were less than favourable it could easily soak up quite a bit of power.
#19
Non omnino gravis
As a non racing, strictly solo rider who's had power for about 4 years now, I'm less interested in seeing a big number than I am seeing a better ratio of W/mph. I'm getting older by the day, so it's unlikely my FTP is going to increase unless I put in a great deal of work I have no desire to do, but body positioning and smarter terrain handling... I can do that for free. A power meter is great for measuring efficiency, too.
#20
OK - I just finished my experiment. I mounted my Favero Assioma Duo power meter pedals on my Peloton bike and ran the zero calibration routine in the app. I did a 60-minute "Power Zone Endurance Ride," which was a long warm-up, followed by four 9-minute Zone 3 intervals, with Zone 2 breaks in between (i.e., it's a very steady, moderate workout).
According to Peloton, I averaged 158 watts, with a total output of 568 kJ.
According to the Faveros (using the Cyclemeter app on my iPhone), I averaged 175 watts with a total output of 632 kJ.
So, in my case, the Peloton was too too low by approximately 10%. I will attempt to use the Peloton calibration kit one of these days and see if I can get the Peloton more in line with my pedals, and then I will have to retake my FTP test.
[By the way, I used my Apple Watch to monitor my HR for Cyclemeter, and a Scoshe Rhythm 24 armband to monitor my HR for Peloton. They were virtually identical the entire ride.]
Call me DC Rainmaker Jr.
According to Peloton, I averaged 158 watts, with a total output of 568 kJ.
According to the Faveros (using the Cyclemeter app on my iPhone), I averaged 175 watts with a total output of 632 kJ.
So, in my case, the Peloton was too too low by approximately 10%. I will attempt to use the Peloton calibration kit one of these days and see if I can get the Peloton more in line with my pedals, and then I will have to retake my FTP test.
[By the way, I used my Apple Watch to monitor my HR for Cyclemeter, and a Scoshe Rhythm 24 armband to monitor my HR for Peloton. They were virtually identical the entire ride.]
Call me DC Rainmaker Jr.
#21
There are a lot of unknown variables here though. We don't know OP's weight, how hilly the ride is, how aero he is on the bike. We know he is on a gravel bike but don't know what tyres/tubes.
If a number of these were less than favourable it could easily soak up quite a bit of power.
If a number of these were less than favourable it could easily soak up quite a bit of power.
#22
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160lbs. I'm trying to be more aero on the bike, but still learning. I am running tubeless 32m GP5000 on the stock wheels, but just got new aero wheels I've yet to try (mostly because I wanted a decent road and gravel wheelset to swap between)...interested to see if I notice any difference between aero wheels. They are almost exactly the same weight as the stock wheels and both carbon.
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#23
I would disregard the power numbers from your Peloton. It measures power in a different way and really isn't applicable or translate over to comparing power on a regular bike. It can be an ego blow that your real power numbers are lower than what the Peloton said, but just forget about that and move on.
It's even hard to compare power numbers across different types of power meters. My first power meter was a single sided pedal meter, and it always read higher than my indoor trainer and other power meters I've tried. I now realize those pedals likely read high. My new power pedals read very close to my indoor trainer and my wife's indoor trainer, so I trust them.
In any event, just go by what your current power meter says.
It's even hard to compare power numbers across different types of power meters. My first power meter was a single sided pedal meter, and it always read higher than my indoor trainer and other power meters I've tried. I now realize those pedals likely read high. My new power pedals read very close to my indoor trainer and my wife's indoor trainer, so I trust them.
In any event, just go by what your current power meter says.
#24
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Your 4iiii is correct and your Peloton is wrong. Your Peloton will never be as accurate as an actual strain gauge power meter. 260 watts at 160lbs you would be averaging over 24 mph with no wind on the flat...and you would be doing that for 45 min straight if your peloton data was correct.
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#25
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On the few flat segments around here, 20mph takes me about 185w.
Of the strongest riders that I follow on Strava, none average 260w, and a +20mph average solo ride is very rare (~50'/mile).
Of the strongest riders that I follow on Strava, none average 260w, and a +20mph average solo ride is very rare (~50'/mile).