step 1, invent a made up idea of first and 2nd generation power meters, define the 2nd generation kind as being the one you are selling:


Add unsubstantiated assertion scare tactic:


Ignore that it is an aerobic sport, and there is no free lunch. Strengthening the weaker leg will pull from the same fountain of aerobic energy, total power is not going to go up:


Credit where credit is due - this is completely accurate:

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

There's more info on the dedicated icranks website. It seems the detailed torque analysis software is $2k on top of the $3.1k price of the icranks:
http://icranks.com/shop/
Plus many people won't already have a suitable phone to record the full data, so the price of that plus dongle needs to be added as well. Starts to get pretty expensive.

[quote Steve IrwinIt seems the detailed torque analysis software is $2k on top of the $3.1k price of the icranks[/quote]
I had to check the site myself to believe that. $2k for just the software?? I just... wow.

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MS: Exercise Science
Your speed matters a lot, sometimes you need to be very fast, where sometimes you need to breakdown your speed.

I think your complete post nailed it jackmott.

I singled out this bit in particular because this is the USP of the Polar Keo Pedals (Left / Right measurements). This makes me curious about how the website can claim to be "iCranks, the first second generation power meter" when Polar / LOOK are on the market about a year now.

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#GottaRun
http://twitter.com/runningmatters_
http://www.feileacanmor.com

IKnowEverything wrote:

[quote Steve IrwinIt seems the detailed torque analysis software is $2k on top of the $3.1k price of the icranks

I had to check the site myself to believe that. $2k for just the software?? I just... wow.[/quote]

Are the bungee cords included?

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My tiny little slice of the internets: dcrainmaker.com

Or when I road a PM that never came to market over 25 years ago with that capability.

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Styrrell

Given the rest of the pricing scheme, I'd guess they are $500- 600 extra...

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WyoJoe

If you think you can do a thing or think you can't do a thing, you're right - Henry Ford

I saw a guy with the non-power crank version of these a few years ago and they do look cool on the way that they are supposed to teach you how to use your legs independent of each other. With this being said, do you remember with your great school teacher would tell you "don't judge a book by its cover"? Well I have to through that teaching out the window. Did you look at their website? I believe that any self respecting president of a company that uses the words "synergy" and goes to explain how their products are the bomb and fails to hire a graphic designer to manage their web content will not get me to buy their product.

What ever happened to Garmin's power meter?

Does the Look/Polar product actually expose the separate data streams or does it combine them first and just provide a single data stream to the head unit? I think the Look/Polar may just behave as a single power meter, whereas I get the impression the iCranks and Rotor devices will appear as two separate power meters to the head unit.

It (Polar/Look) exposes left/right power. All of the left/right power meters on the market (or in the queue for the market) effectively work the same way when it comes to data. They all have a master/slave system in the pedal where one unit acts as primary, and the second unit a secondary. The secondary unit forward power data to the primary, which is then grouped up and transmitted with two numbers. The total power, and the % power of the right leg. The head unit then decodes this (simple 1st grade math) and gives you power balance (left/right power) in either watts or percentage, plus total power.

It works the same whether it's Polar or ANT+. Different companies implement failover/display differently, but the raw data ends up being almost identical. Down the road we'll see more information at the pedal/cleat level (i.e. directional torque), but I don't expect to see that happen at the head unit level for at least another 1-2 years.

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My tiny little slice of the internets: dcrainmaker.com

DCR, is there anything out there worth looking into that's not a millllllllllion dollars that can give L and R power readings and is reliable/repeatable?

No, not at this time.

The only legit left/right power today on the market is the Polar system.

Up and coming are (in order of availability)

1) Rotor Power system
2) Garmin Vector
3) Brim Brothers
4) Power Pedals
5) Pioneer System

With #2-5 being a wild-ass-guess for true availability.

There's a few others playing around, but nothing I'd consider serious at this time.

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My tiny little slice of the internets: dcrainmaker.com

The iCranks must expose two power meters, as according to this:
http://icranks.com/...cranks-ebrochure.pdf
you can end up with a Garmin reporting multiple power meters detected if you don't get the sequence right when you pair them (see 5 pages from the end). I agree that when using with a Garmin you'll just get the same data as the Polar/Look - overall left/right balance etc, but it sounds like when you use a phone to record their additional data you'll get two fully independent streams of data recorded.

The forthcoming Rotor doesn't seem to work quite the same way, in that it seems to pair with a Garmin differently to the iCranks, without any possibility of multiple power meters being detected, but it does allow both arms to be separately zeroed:
http://power.rotorbike.com/...er_ES_ENG_3_todo.pdf
(page 33/34)
I don't know whether there will be any device capable of picking up two independent data streams from the Rotor to allow production of graphs as shown for the iCranks.

Thanks for the info!

(iCranks)
Yeah, so looking at their docs you linked to their essentially just doing two power meters, and then one acts as a master as noted above. The Garmin unit is only capable of talking to one, so they funnel through #2 through #1, and #1 talks to the Garmin (or whomever). I assume they have additional logic in both

They don't talk to how one unit knows that the other one is a friend vs foe, but I assume they've worked that out (meaning, pairing between the two cranks).

(Rotor)
Rotor simply follows all the normal rules of the road and pairs as a normal power meter using the official 'power balance' specification as published in the ANT+ Power Meter device profile.

Ultimately, once power data from either device hits the Garmin (or hits the ANT+ stream), there's a pretty finite way it's going to look. How you display that data afterwards is up to you (the app).

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My tiny little slice of the internets: dcrainmaker.com

Somewhere, Dr AC is rolling his eyes.

And it's one UGLY website to boot...it makes me think that there is some guy behind it who reminds of this dude who used to sell electronics in the 80's:

http://www.youtube.com/watch?v=4yYGoO5imyY

I will say this...I do have big problems with 1 leg doing a lot more work than the other...bad form from a poor initial fit back in 2009. I asked DC about this b/c it would be awesome to get a fairly cheap device that could measure exactly what each leg is doing. That is something I'd certainly pay for...but 2/3 of what my bike costs!

Actually, when you look at what he was trying to measure in this series of articles:
http://www.trainingandracingwithapowermeter.com/...fiber-type-from.html
I'd have thought he might be quite interested in high temporal resolution data such as it appears it will be possible to gather from the iCranks.

Interesting that his test subject can push more than 3 times as much with one leg than I can with both for even a few minutes at at time

i've soooo missed the powercrank argument threads of yore.

thank you for giving people something new to argue about with respect to PCs.

The subject was doing around 300W per leg. The peak power levels shown are not reported by conventional powermeters. The subject wasn't holding those power levels for a few minutes either.

And he didn't give a time duration, (at least I couldn't find it) so if it was for a really short duration it appears to inflate the effect he is arguing.

I have tried and I've been unable to produce more than 650 watts with both legs from a standstill for even 15 seconds, now I'm fairly small and I would expect larger people to put out more for a short period. For someone to claim near 500 watts per leg just seems misleading even if the guy/gal is a weight lifter and 300 lbs.

Maybe I'm missing the point or see the intentional missleading?
Now I'm not arguing that what he is doing is correct or not just that the example provided looks fishy.

No, there's nothing fishy about the measurements he's showing. If you can do 650W for 15S your peak power would be significantly higher.

However, the peak power you see on your powertap or SRM is not a true peak power. It's the highest power averaged over a complete crank revolution (SRM) or over a 1 second time period (Powertap). It's common for cyclists to have a peak power (as recorded by a powermeter) of 1000W+. If your power meter indicates your peak power is 1000W the actual peak power when the pedal is at 3 o'clock would be approx double or 2000W for a single leg.