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2011-10-27 10:00 AM
in reply to: #3740017

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Subject: RE: Power meter question!
colinphillips - 2011-10-27 7:49 AM

Fred D - 2011-10-27 3:30 AM

To *me* I wanted a power meter that I could use for different bikes and also for race and non-race wheels. 

That's exactly my priority. And I'm not terribly handy, and would like something that I could easily put on bikes in different places. So I'm sitting tight waiting for the pedal/shoe-based power-meters (Garmin, Brim Brothers) to hit the market. ... And then I'll probably continue to sit tight for a while longer, dreaming of the time when competition or demand sends the price below $1000.

There are some good discussions of the development progress of the new power-meters on dcrainmaker.com (unsurprisingly). 



yeah... me too. I'm getting impatient, though! Wish they were hitting the market a little earlier in 2012.....


2011-10-27 10:12 AM
in reply to: #3739351

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Subject: RE: Power meter question!

And just since people seemed to have not focused on Tom's 'digs' on PTs, I have a wired version that I bought in 2007.  It still works perfectly despite destroying the wheel that it was initially housed in.  The accuracy of the data is excellent in PTs and they don't require recalibration for the most part.  The fact that it includes power loss from the drive-train is irrelevant unless your drive train loses efficiency--in which case, that might be a nice thing to know!

Also, 'asymmetry' in your pedal stroke (a supposed advantage of the Garmin) is also irrelevant.  I do hope that Garmin comes out with an excellent product.  And one that will eventually help lower the entry to power cost for more users.  But there are very good options on the market today.  And, I am with Fred in that I would not make an investment in a power system before giving the product some time to be tested by consumers.  It's not just the technology, but the manufactuing and support that matters.  Garmin's track-record and resources notwithstanding, everyone can make mistakes with new products/pocesses.

2011-10-27 10:19 AM
in reply to: #3740388

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Subject: RE: Power meter question!
JohnnyKay - 2011-10-27 11:12 AM

And just since people seemed to have not focused on Tom's 'digs' on PTs, I have a wired version that I bought in 2007.  It still works perfectly despite destroying the wheel that it was initially housed in.  The accuracy of the data is excellent in PTs and they don't require recalibration for the most part.  The fact that it includes power loss from the drive-train is irrelevant unless your drive train loses efficiency--in which case, that might be a nice thing to know!

Do you mean that you destroyed the wheel? Or that the PT destroyed the wheel (not such a ringing endorsement)?

(I'm interested in the answer for a variety of reasons.)

2011-10-27 10:22 AM
in reply to: #3740408

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Subject: RE: Power meter question!
colinphillips - 2011-10-27 11:19 AM
JohnnyKay - 2011-10-27 11:12 AM

And just since people seemed to have not focused on Tom's 'digs' on PTs, I have a wired version that I bought in 2007.  It still works perfectly despite destroying the wheel that it was initially housed in.  The accuracy of the data is excellent in PTs and they don't require recalibration for the most part.  The fact that it includes power loss from the drive-train is irrelevant unless your drive train loses efficiency--in which case, that might be a nice thing to know!

Do you mean that you destroyed the wheel? Or that the PT destroyed the wheel (not such a ringing endorsement)?

(I'm interested in the answer for a variety of reasons.)

Sorry for the unclear statement.  *I* destroyed the wheel (hit a pothole while racing the Philly Tri and twisted the rim).  The PT was just along for the ride. 

 

Edit:  And, as an aside and an added plug for a company with exceptional customer service, I sent the PT hub back to wheelbuilder.com (Rich Sawris) who quickly rebuilt and shipped the wheel back in great condition.  I cannot recommend the company highly enough for anyone looking at a PT (or any other wheel) and/or wheelcover.



Edited by JohnnyKay 2011-10-27 10:28 AM
2011-10-27 10:33 AM
in reply to: #3740017

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2011-10-27 10:46 AM
in reply to: #3739351

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Subject: RE: Power meter question!

JohnnyKay's happiness with his PT is inline with mine!  I bought a used wireless PT two years ago (laced to a Mavic OpenPro).  I've changed the batteries in it and that's about it--it just works.  I do think a lot depends upon people's priorities/planning.  I decided early on that I wanted power first and race wheels second---in other words I only had training wheels.  So I bought the PT laced to the bomb proof training wheel and got a cover then went out and found a front race wheel---and I did all that for the price of a quarq.  That's NOT a knock on quarq!!  I'd love to have a quarq but well to say money is tight is an understatement and I didn't want to deal with a BB adapter (roadbike is BB30 and the tribike is GXP).  I easily swap the rear wheel between bikes and spend 15mins before a race to take the cassette off the wheel and put the cover on---this also gives me a chance to make sure my drive train is clean before a race!! 

I'm all for Garmin and the others to jump into the power game---can only help all of us--but for right now I'm staying with what I have.  Any thoughts on stripping the pedals from constantly swapping them between bikes??  I only ask because I've seen that question raised elsewhere---as in cross threading, etc....



2011-10-27 11:02 AM
in reply to: #3740480

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Subject: RE: Power meter question!
Skippy74 - 2011-10-27 8:46 AM

JohnnyKay's happiness with his PT is inline with mine!  I bought a used wireless PT two years ago (laced to a Mavic OpenPro). 

I too have a PT laced on a Mavic OpenPro and couldn't be happier. After doing a lot of research I decided that for me, the cost/benefit tradeoff between PT/Quarq/SRM was in favor of the PT and I couldn't be happier w/ that decision.

2011-10-27 11:04 AM
in reply to: #3739351

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Subject: RE: Power meter question!

I have a PT laced to my Reynolds Assault and love it.  Both training wheel and race wheel.  '

The Garmin pedal intrigues me, but at $1500 I'd rather keep my PT and get some Zipp Firecrest.  

2011-10-27 11:29 AM
in reply to: #3740553

Elite
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Subject: RE: Power meter question!

I would suggest that, where we stand now (as in, on today's date) in the technology stream, PowerTap is the best option for power measurement.

That isn't to say that some new system does not have the capability to eclipse it.

I saw PowerTap's new wheels and hubs about three weeks ago and got a chance to do a photo shoot with them. They've made significant improvements.

It will be interesting to see how consumers behave when the new option from Garmin enters the market. Legacy technology owners are initially irked when new stuff comes out, and there is a phase of pooh-poohing it as they try to convince themselves they did the right thing and don't want or "need" to replace their existing equipment. It usually takes two years minimum, about the life cycle of the product or user experience itself, for that to go away and the paradigm to shift.

The fact of the matter is the equipment they originally bought is still as good as the day they bought it, the technology stream has just passed it and creates a perception that their existing equipment is somehow "no good anymore" when, in fact, it is as fine as the day they bought it.

2011-10-27 11:33 AM
in reply to: #3739351

Carrollton, TX
Subject: RE: Power meter question!

Count me in on waiting for the Garmin vector (and proving itself to be without a lot of issues).  I really like the idea of being able to switch out pedals between bikes (road and tri).  I have various wheelsets that I'd like to be interchangeable as well.

I have some goals for some races next year, and should I meet those I will reward myself for my hard work by getting whichever PM I decide. 

2011-10-27 11:36 AM
in reply to: #3739351

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Subject: RE: Power meter question!
Tom, I'm curious what, if anything, you know about the Brim Brothers Zone (shoe/cleat based) power meter. Any thoughts?


2011-10-27 12:06 PM
in reply to: #3740612

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Subject: RE: Power meter question!
Tom Demerly. - 2011-10-27 12:29 PM

I would suggest that, where we stand now (as in, on today's date) in the technology stream, PowerTap is the best option for power measurement.

That isn't to say that some new system does not have the capability to eclipse it.

I saw PowerTap's new wheels and hubs about three weeks ago and got a chance to do a photo shoot with them. They've made significant improvements.

It will be interesting to see how consumers behave when the new option from Garmin enters the market. Legacy technology owners are initially irked when new stuff comes out, and there is a phase of pooh-poohing it as they try to convince themselves they did the right thing and don't want or "need" to replace their existing equipment. It usually takes two years minimum, about the life cycle of the product or user experience itself, for that to go away and the paradigm to shift.

The fact of the matter is the equipment they originally bought is still as good as the day they bought it, the technology stream has just passed it and creates a perception that their existing equipment is somehow "no good anymore" when, in fact, it is as fine as the day they bought it.

At this stage, it remains very unclear to me what is 'superior' about a pedal based system aside from it offering incrementally more flexibility in switching between bikes.  That's a nice benefit, don't get me wrong.  But, in your first post, you essentially 'bashed' the other products for some reason--noting the point where they measured power made them inferior (that's not an issue).

So, if the Garmin offers some other technological leap or provides some cost advantage--neither appears to be the case at the expected launch--then I'm sure people will gravitate towards it quickly.  Otherwsie, the 'convience' of the pedal form factor is only likely to influence people much more gradually--as you note, their existing PM is just as good as the day they bought it--and will be considered along with price and other considerations.  The strain guage difference is interesting, but I don't really see the big advantage as the guages from the other manufacturers seem to already last quite a long time regardless of riding conditions.

I'm not "pooh-poohing", but I also see only modest advantages and a higher price point.  Nothing compelling to drive me to switch.  Heck, wireless hasn't been enough of an advantage to get me to switch.  The wired PT "just works".

2011-10-27 12:07 PM
in reply to: #3740633

Elite
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Subject: RE: Power meter question!

"Tom, I'm curious what, if anything, you know about the Brim Brothers Zone (shoe/cleat based) power meter. Any thoughts?"

I've only been exposed to it through web resources like this:

http://www.brimbrothers.com/2011/06/announcing-zone/

It looks like its in the early-ish stages of development. Interesting though.

2011-10-27 12:10 PM
in reply to: #3740709

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2011-10-27 12:14 PM
in reply to: #3740612

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2011-10-27 12:23 PM
in reply to: #3740709

Elite
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Laguna Beach
Subject: RE: Power meter question!

"At this stage, it remains very unclear to me what is 'superior' about a pedal based system aside from it offering incrementally more flexibility in switching between bikes."

A compromise to current power measurement units in cycling is the existing strain gauge technology used in current power meters.

Current brands and models use a foil strain gauge. Here is an introduction to strain guage technology and a discussion of the foil strain gauge developed in 1938:

http://www.omega.com/prodinfo/StrainGages.html

The newer strain guages are silicone strain gauges and "provide an accurate, stable signal over a wide operating temperature range (-40 to +140°C), as well as temperature compensation." (source: sensata technologies, microfused silicon strain gauge for hermetic pressure sensing)

Silicone strain gauges are more stable and produce more repeatable data for an elastic force application such as power measurement through an elastic drivetrain, like a pedal axle that flexs some. In automotive high end, such as BMW, Volvo and Mercedes, these silicone strain guages monitor brake pressure, vehicle ride control such as stability systems, transmission behavior and even sense the changing weight of passengers to adjust the suspension of the car (BMW).

Other brands will switch to silicone sensors and bring their power measurement closer to where the force is appllied- at the pedals- instead of where the result occurs- at the wheel. This closer proximity to the origin of the forces will provide a much more accurate, repeatable and detailed insight into how forces are being applied.

Another huge capability, in addition to independent measurement of force application where it is applied, is an accurate measurement of tangenital and radial force. In other words- the quality of your pedal stroke: Are you applying force to the pedal with the best angular relationship? The Garmin unit has the capability to provide an accurate and precise measurement of those force tangents.



Edited by Tom Demerly. 2011-10-27 12:25 PM


2011-10-27 12:27 PM
in reply to: #3739351

Coach
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Subject: RE: Power meter question!

I've been a powertap owner for almost 6+ years now and I've been very happy with their reliability and customer service. Recently through a sponsor I got my hands on a Quarq which I'll test on cyclocross. So far the system looks good and works great.

I think you can't go wrong with either powertap or Quarq, both provide advantages and disadvantages. Both have great customer service (in my experience so far) and both are very reliable. I would be hesitant to try the pedal based systems right off the bat. Having own garmin GPS and the many headaches I've had with software and service I would certainly wait ti see the reliability of the system 1st.

As a side note - every year I help coordinate a group buy for powertaps and this year will be no exception. The details will be ready in a day or two (I am waiting as I type) so if you can wait a few days, I'll let BT know very soon!

2011-10-27 12:31 PM
in reply to: #3740729

Coach
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Subject: RE: Power meter question!
Fred D - 2011-10-27 12:14 PM
Tom Demerly. - 2011-10-27 12:29 PM

I would suggest that, where we stand now (as in, on today's date) in the technology stream, PowerTap is the best option for power measurement.

That isn't to say that some new system does not have the capability to eclipse it.

I saw PowerTap's new wheels and hubs about three weeks ago and got a chance to do a photo shoot with them. They've made significant improvements.

 

I agree, but this is in sharp contrast to what you said yesterday, which is really what set off my response:

 That said, it is still a crank based power measurement unit, much better than a rear wheel based unit like PowerTap since the accuracy of the data isn;t at all modified by the transmission of force through the drivetrain

I just don't buy into any inferiority of PT. Only knock is the race wheel/training wheel issue imho. Company has great track record and even better customer service.

indeed. besides, there are research papers available comparing different systems and time after time powertap performs as good as some of the crank based systems so Tom is basically just expressing his opinion. 
2011-10-27 12:38 PM
in reply to: #3740754

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Subject: RE: Power meter question!
Tom Demerly. - 2011-10-27 1:23 PM

"At this stage, it remains very unclear to me what is 'superior' about a pedal based system aside from it offering incrementally more flexibility in switching between bikes."

A compromise to current power measurement units in cycling is the existing strain gauge technology used in current power meters.

Current brands and models use a foil strain gauge. Here is an introduction to strain guage technology and a discussion of the foil strain gauge developed in 1938:

http://www.omega.com/prodinfo/StrainGages.html

The newer strain guages are silicone strain gauges and "provide an accurate, stable signal over a wide operating temperature range (-40 to +140°C), as well as temperature compensation." (source: sensata technologies, microfused silicon strain gauge for hermetic pressure sensing)

Silicone strain gauges are more stable and produce more repeatable data for an elastic force application such as power measurement through an elastic drivetrain, like a pedal axle that flexs some. In automotive high end, such as BMW, Volvo and Mercedes, these silicone strain guages monitor brake pressure, vehicle ride control such as stability systems, transmission behavior and even sense the changing weight of passengers to adjust the suspension of the car (BMW).

Other brands will switch to silicone sensors and bring their power measurement closer to where the force is appllied- at the pedals- instead of where the result occurs- at the wheel. This closer proximity to the origin of the forces will provide a much more accurate, repeatable and detailed insight into how forces are being applied.

Another huge capability, in addition to independent measurement of force application where it is applied, is an accurate measurement of tangenital and radial force. In other words- the quality of your pedal stroke: Are you applying force to the pedal with the best angular relationship? The Garmin unit has the capability to provide an accurate and precise measurement of those force tangents.

I don't need -40 to +140°C range.  More like 10 to +110F.  I have not seen any noticible change in my PT across temps, but I'll concede there might be a small advantage here to the silicone (not likley one that would drive a purchase decision unless the difference is clearly measureable on a bike).

The 'source of force' application advantage is still not readily apparent to me.  What matters is the force moving the wheel.  I do not see how the the drive trian loss impacts how I look at the data.  Might matter for academic studies, but that's certainly not the mass market.

The pedal storke stuff opens up another can-of-worms debate, but I see absolutely no value in that.  It's like spinscan.  Sounds cool.  Helps me go faster, how? (Please don't answer that, it was rhetorical--it doesn't.)

2011-10-27 12:42 PM
in reply to: #3739351

Carrollton, TX
Subject: RE: Power meter question!

I agree, Tom is expressing his opinion.  But he is 100% correct that this is the correct direction for the technology to evolve: measuring the power at the point of application, versus making assumptions based on the result.

Another point is that while this initial offering will be no cheaper than other options (~2x more expensive than the cheapest option in fact), is that Garmin has huge brand recognition and will finally bring power to the masses if they can get to the mythical $1k price point in my opinion, simply due to the fact that changing pedals is very easy even for the most mechanically challenged.  That, and the purchase does not limit you to a particular wheel or crankset, they are interchangeable across all bikes, current and future.  It is absolutely to the benefit of consumers for more competition to come into play in this niche market, and for that, I don't see how anybody could be upset about Garmin coming out with a product.  If it sucks, it sucks, and nobody will buy it.

2011-10-27 12:47 PM
in reply to: #3740795

Elite
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Laguna Beach
Subject: RE: Power meter question!

I think another advantage to any pedal based power system for some users is simplicity and ease of use.

It is easier to switch pedals from one bike to another whereas with crank based systems there is more work and with wheel based systems switching from race wheels to training wheels is more expensive.

One drawback to pedal based systems is, at this time, you're married to one pedal system. Although Garmin did "acknowledge" that limitation with an inflection that may suggest on going developments. Or it may not.

Don't dismiss the angular force application metric either. That is huge. If most people had an idea of how many watts they leave on the table with less than optimzed pedal technique they would suddenly be intersted in angular force. It's "free work". Dr. Frank Day and his Powercranks demonstrate that. Angular force application is a metric worthy of collecting and acknowledging.



2011-10-27 12:52 PM
in reply to: #3740807

Elite
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Laguna Beach
Subject: RE: Power meter question!

"Tom is expressing his opinion."

With respect, be careful Sir. I have not rendered an opinion. I am stating the facts of the product introduction as represented to me by Garmin and supported by the citations I inserted in each post.

I do not have an opinion on the product's validity yet beyond suggesting Garmin makes a strong case for it with some already known empiracles. The facts look compelling.

As for my opinion, I reserve that for when I get to experience how the unit actually works and what it is like to live with for a while. Then I'll render an opinion about what I think of it.

Until then, I would suggest Garmin has presented a strong factually supported case for their product. That warrants further evaluation.

2011-10-27 12:57 PM
in reply to: #3740807

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2011-10-27 1:02 PM
in reply to: #3740830

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2011-10-27 1:02 PM
in reply to: #3740852

Elite
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Laguna Beach
Subject: RE: Power meter question!

We will indeed Sir.

Thank you- Smile

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