Ergomo and Power Tap comparison

[Robert Chung]

Some of you may know that the Ergomo bottom bracket-based power meter has recently entered the
market. Although some Ergomo dealers have done private testing and comparisons of their systems,
until now there has not been any publicly-available data set that could be used for independent
evaluation. Last week, Ergomo-USA put some data files on their website that were collected during a
two-hour ride on a bike equipped with both the Ergomo and the Power Tap Pro hub. I've had a chance
to examine the data and my comments are here:
http://mywebpage.netscape.com/rechung/wattage/ergomo/ergomo-pt.html

I have previously examined data from a ride where three different power meters were installed: the
SRM, the Power Tap, and the Polar S710 with optional power module. That write-up can be found via
the link at: http://mywebpage.netscape.com/rechung/wattage

 

[Phil Holman]

"Robert Chung" <[email protected]> wrote in message news:[email protected]...
> Some of you may know that the Ergomo bottom bracket-based power meter
has
> recently entered the market. Although some Ergomo dealers have done private testing and
> comparisons of their systems, until now there has
not
> been any publicly-available data set that could be used for
independent
> evaluation. Last week, Ergomo-USA put some data files on their website that were collected during
> a two-hour ride on a bike equipped with
both
> the Ergomo and the Power Tap Pro hub. I've had a chance to examine the data and my comments are
> here: http://mywebpage.netscape.com/rechung/wattage/ergomo/ergomo-pt.html
>
> I have previously examined data from a ride where three different
power
> meters were installed: the SRM, the Power Tap, and the Polar S710 with optional power module. That
> write-up can be found via the link at: http://mywebpage.netscape.com/rechung/wattage
>

Thanks for supplying the info Robert. Interesting to see another power measuring device that
probably doesn't perform any better than a Powertap at almost twice the price. I would like to see
the business plan for this device. I like the longer sampling rate which will eliminate the annoying
frequent reading changes of the Powertap. The higher reading is expected due to drivetrain losses
although one would expect to see this as a percentage and not a constant. Of course when measuring
only one leg the device can be deliberately fooled. I don't see this as a flaw but don't pay too
much attention to your readings when doing one legged drills with either leg.

Phil Holman

 

[Scott Patton]

In article <[email protected]>, Phil Holman
<[email protected]> wrote:
>
>Thanks for supplying the info Robert. Interesting to see another power measuring device that
>probably doesn't perform any better than a Powertap at almost twice the price.

Let's get the facts straight:

MSRP:
- PT w/Training Wheel - $799
- PT Pro w/Training Wheel - $999
- PT w/Race Wheel - $1099
- PT Pro w/Race Wheel - $1299
- Ergomo Sport - $1289

Now, I would also argue that if you go with a PT option, you need to pick up a copy of CyclingPeaks
Software as the PT software is pathetic! That's another $75.

I think it's pretty hard to call that "almost twice". There are some other significant advantages to
the Ergomo, including:

o Use your own wheels. o Rechargable battery. o Lighter o hardwired computer eliminates data drops

There are others, you can find details @ http://www.ergomo-usa.com.

Scott


--
-*- Scott Patton -*- Colorado Springs, CO -*- http://www.FixedGearFever.com -*- Track Racing
Web Services

 

[Phil Holman]

"scott patton" <[email protected]> wrote in message news:[email protected]...
> In article <[email protected]>, Phil Holman
> <[email protected]> wrote:
> >
> >Thanks for supplying the info Robert. Interesting to see another
power
> >measuring device that probably doesn't perform any better than a Powertap at almost twice
> >the price.
>
> Let's get the facts straight:
>
> MSRP:
> - PT w/Training Wheel - $799
> - PT Pro w/Training Wheel - $999
> - PT w/Race Wheel - $1099
> - PT Pro w/Race Wheel - $1299
> - Ergomo Sport - $1289

Still as fiesty as ever Scott. The market demand for such devices being able to support several
companies is questionable. I thought the $300 I paid for my PT was OK. It was used but the hub had
just been replaced and personally, I wouldn't pay over $1000 for one. This from their website.....
"Fortunately for the consumer, there are several options on the market to choose from. At $1279, the
Ergomo Sport® is a great value considering that the comparable competitor retails for more than
twice the price"........

They obviously don't consider the PT as being comparable.......more straight facts no doubt.

>
> Now, I would also argue that if you go with a PT option, you need to
pick
> up a copy of CyclingPeaks Software as the PT software is pathetic!
That's
> another $75.
>
> I think it's pretty hard to call that "almost twice". There are some
other
> significant advantages to the Ergomo, including:
>
> o Use your own wheels. o Rechargable battery. o Lighter o hardwired computer eliminates data drops

Using your own wheels is good and you could possibly use this on a track bike if you can get the
chainline right. There's a little extra hassle when moving this to another bike unless you buy
another BB sensor.

Phil Holman

 

[Andy Coggan]

"Phil Holman" <[email protected]> wrote in message
news:[email protected]...

> The higher reading is expected due to drivetrain losses although one would expect to see this as a
> percentage and not a constant.

While people frequently state that X% of power is lost in the drivetrain, in fact this percentage
declines with increasing power output - IOW, it appears to be partially, if not largely, a constant.
This makes sense when you consider that 1) most of the friction in the chain reportedly arises as a
result of the links bending around one another, and is not due to rubbing of the bushings on cogs or
chainrings, and 2) on a geared bike, the chain bends the most wrapping around the derailleur
pulleys, i.e., on the lower run where the tension is independent of power output.

Andy Coggan.

 

[Phil Holman]

"Andy Coggan" <[email protected]> wrote in message
news:[email protected]...
> "Phil Holman" <[email protected]> wrote in message
> news:[email protected]...
>
> > The higher reading is expected due to drivetrain losses although one
would
> > expect to see this as a percentage and not a constant.
>
> While people frequently state that X% of power is lost in the
drivetrain, in
> fact this percentage declines with increasing power output - IOW, it
appears
> to be partially, if not largely, a constant. This makes sense when you consider that 1) most of
> the friction in the chain reportedly arises
as a
> result of the links bending around one another, and is not due to
rubbing of
> the bushings on cogs or chainrings, and 2) on a geared bike, the chain
bends
> the most wrapping around the derailleur pulleys, i.e., on the lower
run
> where the tension is independent of power output.

Good point. One would therefore expect to see a difference in Ergomo readings between very high and
very low cadences for a given power on a PT reading.

Phil Holman

 

[Jim Martin]

"scott patton" <[email protected]> wrote
> There are others, you can find details @ http://www.ergomo-usa.com.

Thanks for the link Scott. Just looking at the device, it seems to me that it can only measure
torque carried by the bottom bracket spindle which means it can only measure left leg power/torque.

If you are just using it to follow your own training it might not matter. Then again, you might
adopt a left pedal power style to get bigger numbers ;-) Can't imagine paying that much for a device
with such a large inherent assumption.

Cheers,

Jim

---
Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com).
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[Nick Burns]

"Robert Chung" <[email protected]> wrote in message news:[email protected]...
> Some of you may know that the Ergomo bottom bracket-based power meter has recently entered the
> market. Although some Ergomo dealers have done private testing and comparisons of their systems,
> until now there has not been any publicly-available data set that could be used for independent
> evaluation. Last week, Ergomo-USA put some data files on their website that were collected during
> a two-hour ride on a bike equipped with both the Ergomo and the Power Tap Pro hub. I've had a
> chance to examine the data and my comments are here:
> http://mywebpage.netscape.com/rechung/wattage/ergomo/ergomo-pt.html
>
> I have previously examined data from a ride where three different power meters were installed: the
> SRM, the Power Tap, and the Polar S710 with optional power module. That write-up can be found via
> the link at: http://mywebpage.netscape.com/rechung/wattage

Until I found out it only measures one side, I thought this was potentially the best system. You can
use virtually all of your own equipment, and other great features. Measuring one leg could be a deal
breaker for me, especially if the athlete has no way to determine what his or her power distribution
is. I have seen many athletes that have more slow twitch pwer on the non dominant leg and of course
more fast twitch on the dominant side.

What a let down. I guess it still serves a lot of purpose, it is just not as ideal as I had thought.

How is the softwares? What is the raw data format?

Thanks Robert

 

[Robert Chung]

Phil Holman wrote:
> One would therefore expect to see a difference in Ergomo readings between very high and very low
> cadences for a given power on a PT reading.

This is why I was trying to identify the gear ratios used, and why my comments may seem overly
obsessed with cadence -- I need to use speed and cadence to figure out exactly when the switch is
made from one gear ratio to another. I was trying to figure out whether there was a difference in
recorded power based on the chainwheel-cog combination being used. An annoying side issue in my
analysis was that the two wheel circumferences weren't set exactly the same, and I needed to fiddle
with them to figure out which circumference may have been closer (since the cadence was so flaky, I
need pretty good info on speed in order to differentiate between similar numeric gear ratios that
come from a small chainring-small cog combo vs. a large chainring-medium cog combo).

As to whether the Ergomo is worth the money, I have no opinion. I've never used either of these two
devices. This wasn't a comparison of features or usability, which other people have done. I was
simply looking at the quality of the power data, which others haven't. I think the evidence from a
sample size of 1 is that consistency of power measurement doesn't appear to be an issue to worry
about, and you should decide based on features and usability and reliability (and price).

 

[Andy Coggan]

"Nick Burns" <[email protected]> wrote in message
news:[email protected]...

> How is the softwares? What is the raw data format?

The Ergomo comes with a customized version of the best powermeter software on the market:
www.cyclingpeakssoftware.com. That means the data are saved
in .wko format, but of course can be exported in any form your heart desires (.csv for PowerTap,
.txt for SRM, .??? for Polar, etc.).

Andy Coggan

 

[Scott Patton]

In article <[email protected]>, Phil Holman
<[email protected]> wrote:
>
>"scott patton" <[email protected]> wrote in message news:[email protected]...
>> In article <[email protected]>, Phil Holman
>> <[email protected]> wrote:
>> >
>> >Thanks for supplying the info Robert. Interesting to see another
>power
>> >measuring device that probably doesn't perform any better than a Powertap at almost twice the
>> >price.
>>
>> Let's get the facts straight:
>>
>> MSRP:
>> - PT w/Training Wheel - $799
>> - PT Pro w/Training Wheel - $999
>> - PT w/Race Wheel - $1099
>> - PT Pro w/Race Wheel - $1299
>> - Ergomo Sport - $1289
>
>Still as fiesty as ever Scott.

Huh? Just getting facts out so we can talk about them.

> The market demand for such devices being able to support several companies is questionable. I
> thought the $300 I paid for my PT was OK. It was used but the hub had just been replaced and
> personally, I wouldn't pay over $1000 for one.

It really depends on what you want. Many people wouldn't bay $500+ for a crankset you aren't going
to race on.

All of the power meters are tools to optimize your training, if use properly.

> This from their website..... "Fortunately for the consumer, there are several options on the
> market to choose from. At $1279, the Ergomo Sport® is a great value considering that the
> comparable competitor retails for more than twice the price"........ They obviously don't consider
> the PT as being comparable.......more straight facts no doubt.

I am very up on what the web page says (I am the guy that did it). In many ways I consider them
comparable. Others, I do not. To most cat 3's with the whole weight weenie race wheel thing going
on, PT and Ergomo are NOT comparable. You cant race with a light rear wheel with a PT. You can
howerver run disco wheels with an SRM or an Ergomo.

I am a dealer of both PT and Ergomo. I don't try to sell one of the other based on price, rather on
what will you use it for?

>> Now, I would also argue that if you go with a PT option, you need to
>pick
>> up a copy of CyclingPeaks Software as the PT software is pathetic!
>That's
>> another $75.
>>
>> I think it's pretty hard to call that "almost twice". There are some
>other
>> significant advantages to the Ergomo, including:
>>
>> o Use your own wheels. o Rechargable battery. o Lighter o hardwired computer eliminates
>> data drops
>
>Using your own wheels is good and you could possibly use this on a track bike if you can get the
>chainline right. There's a little extra hassle when moving this to another bike unless you buy
>another BB sensor.

VERY true. Using an Ergomo on 2 bikes is a challenge! The same applies for an SRM.

We are working on some fixed gear testing, but the Campy Triple model is the same bottom bracket
(size) as a campy track bottom bracket. Chainline should be just fine! More on that soon!

Scott

--
-*- Scott Patton -*- Colorado Springs, CO -*- http://www.FixedGearFever.com -*- Track Racing
Web Services

 

[Scott Patton]

In article <[email protected]>, Nick Burns
<[email protected]> wrote:
>
>Until I found out it only measures one side, I thought this was potentially the best system. You
>can use virtually all of your own equipment, and other great features. Measuring one leg could be a
>deal breaker for me, especially if the athlete has no way to determine what his or her power
>distribution
>is. I have seen many athletes that have more slow twitch pwer on the non dominant leg and of course
> more fast twitch on the dominant side.

While the ride Robert tore apart is only one ride, we are finding that people riding both a PT and
Ergomo are coming up much like the analyzed ride.

>How is the softwares? What is the raw data format?

The software is called ErgoRacer and is the same as CyclingPeaks Software.

www.CyclingPeaksSoftware.com

It far exceeds other power analysis software!

It stores the data in a proprietary .wko format. It can however export to .csv, .txt and other major
formats to share files with people not using CyclingPeaks Software.

CPS also integrates the Normalized Power, Training Stress Score and Intensiy Factor made famous by
our own Andy Coggan.

Scott

--
-*- Scott Patton -*- Colorado Springs, CO -*- http://www.FixedGearFever.com -*- Track Racing
Web Services

 

[Chris]

If one wanted to increase their numbers they could just buy an SRM and input a slope coeficient half
that of the one set for their meter. That would give them nice big numbers. Then again, if they
wanted to do that they bought it for other reason besides improving performance...

CH

"Jim Martin" <[email protected]> wrote in message
news:<[email protected]>...
> "scott patton" <[email protected]> wrote
> > There are others, you can find details @ http://www.ergomo-usa.com.
>
> Thanks for the link Scott. Just looking at the device, it seems to me that it can only measure
> torque carried by the bottom bracket spindle which means it can only measure left leg
> power/torque.
>
> If you are just using it to follow your own training it might not matter. Then again, you might
> adopt a left pedal power style to get bigger numbers ;-) Can't imagine paying that much for a
> device with such a large inherent assumption.
>
> Cheers,
>
> Jim
>
>
> ---
> Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.528 / Virus Database: 324 - Release Date: 10/16/2003

 

[Chris]

I can't say that I would agree with your assessment, Phil. One could argue that it's hard to see how
the market could sustain itself selling $1500 wheelsets, which can't improve performance as much as
an effectively utilized power meter. Moreover, power meters have become the new HR monitor with
numerous techno geeks AND serious cyclists looking to buy them. In my experience, many non-elite
riders want to take the plunge to simply train better, and I can't disagree with them (granted, I do
have an interest in them buying).

Having used many of these devices, I would say the Ergomo looks the most promising because of its
simplicity, weight and wheel usage. Whether the leg issue comes into play we'll have to wait and
see, but I don't believe most healthy cyclists have such a (leg) discrepancy that it would come into
play. But we should find out soon.

CH

"Phil Holman" <[email protected]> wrote in message
news:<[email protected]>...
> "scott patton" <[email protected]> wrote in message news:[email protected]...
> > In article <[email protected]>, Phil Holman
> > <[email protected]> wrote:
> > >
> > >Thanks for supplying the info Robert. Interesting to see another
> power
> > >measuring device that probably doesn't perform any better than a Powertap at almost twice the
> > >price.
> >
> > Let's get the facts straight:
> >
> > MSRP:
> > - PT w/Training Wheel - $799
> > - PT Pro w/Training Wheel - $999
> > - PT w/Race Wheel - $1099
> > - PT Pro w/Race Wheel - $1299
> > - Ergomo Sport - $1289
>
> Still as fiesty as ever Scott. The market demand for such devices being able to support several
> companies is questionable. I thought the $300 I paid for my PT was OK. It was used but the hub had
> just been replaced and personally, I wouldn't pay over $1000 for one. This from their website.....
> "Fortunately for the consumer, there are several options on the market to choose from. At $1279,
> the Ergomo Sport® is a great value considering that the comparable competitor retails for more
> than twice the price"........
>
> They obviously don't consider the PT as being comparable.......more straight facts no doubt.

 

[Nick Burns]

"chris" <[email protected]> wrote in message

Moreover, power meters have become
> the new HR monitor with numerous techno geeks AND serious cyclists looking to buy them.

Power meters do not replace HRMs. I would be foolish to track power without heart rate.

 

[Andy Coggan]

"Nick Burns" <[email protected]> wrote in message
news:[email protected]...
>
> "chris" <[email protected]> wrote in message
>
> Moreover, power meters have become
> > the new HR monitor with numerous techno geeks AND serious cyclists looking to buy them.
>
> Power meters do not replace HRMs. I would be foolish to track power
without
> heart rate.

And why is that? (I know of plenty of scientific investigations of exercise responses in which HR
has not been measured, and nobody seems to miss the data...in fact, probably about the only
scientists who view it as indispensable are those studying the cardiovascular responses to
exercise.)

Andy Coggan

 

[Nick Burns]

"Andy Coggan" <[email protected]> wrote in message
news:[email protected]...
> "Nick Burns" <[email protected]> wrote in message
> news:[email protected]...
> >
> > "chris" <[email protected]> wrote in message
> >
> > Moreover, power meters have become
> > > the new HR monitor with numerous techno geeks AND serious cyclists looking to buy them.
> >
> > Power meters do not replace HRMs. I would be foolish to track power
> without
> > heart rate.
>
> And why is that? (I know of plenty of scientific investigations of
exercise
> responses in which HR has not been measured, and nobody seems to miss the data...in fact, probably
> about the only scientists who view it as indispensable are those studying the cardiovascular
> responses to
exercise.)
>
> Andy Coggan

Because CV response is critical.

 

[Scott Patton]

In article <[email protected]>, Nick Burns
<[email protected]> wrote:
>
>"chris" <[email protected]> wrote in message
>
> Moreover, power meters have become
>> the new HR monitor with numerous techno geeks AND serious cyclists looking to buy them.
>
>Power meters do not replace HRMs. I would be foolish to track power without heart rate.
>
>

I think you have that backwards....

http://www.topica.com/lists/wattage/read/message.html?mid=908880634&sort=d&start=15447

Posted today.

Scott

--
-*- Scott Patton -*- Colorado Springs, CO -*- http://www.FixedGearFever.com -*- Track Racing
Web Services

 

[Nick Burns]

"scott patton" <[email protected]> wrote in message news:[email protected]...
> In article <[email protected]>, Nick Burns
> <[email protected]> wrote:
> >
> >"chris" <[email protected]> wrote in message
> >
> > Moreover, power meters have become
> >> the new HR monitor with numerous techno geeks AND serious cyclists looking to buy them.
> >
> >Power meters do not replace HRMs. I would be foolish to track power
without
> >heart rate.
> >
> >
>
> I think you have that backwards....
>
>
http://www.topica.com/lists/wattage/read/message.html?mid=908880634&sort=d&s ****=15447
>
> Posted today.
>
> Scott

It works the same either way you state it. HRMs do not replace power meters either. OK?

> --
> -*- Scott Patton -*- Colorado Springs, CO -*- http://www.FixedGearFever.com -*- Track Racing Web
> Services

 

[Andy Coggan]

"Nick Burns" <[email protected]> wrote in message
news:[email protected]...
>
> "Andy Coggan" <[email protected]> wrote in message
> news:[email protected]...
> > "Nick Burns" <[email protected]> wrote in message
> > news:[email protected]...
> > >
> > > "chris" <[email protected]> wrote in message
> > >
> > > Moreover, power meters have become
> > > > the new HR monitor with numerous techno geeks AND serious cyclists looking to buy them.
> > >
> > > Power meters do not replace HRMs. I would be foolish to track power
> > without
> > > heart rate.
> >
> > And why is that? (I know of plenty of scientific investigations of
> exercise
> > responses in which HR has not been measured, and nobody seems to miss
the
> > data...in fact, probably about the only scientists who view it as indispensable are those
> > studying the cardiovascular responses to
> exercise.)
> >
> > Andy Coggan
>
> Because CV response is critical.

Assuming for sake of argument that you're right, what then do you do with the information that HR
provides you about your cardiovascular response?

Andy Coggan