New powermeter rumours

Discuss light weight issues concerning road bikes & parts.
styrrell
Posts: 167
Joined: Mon Apr 19, 2010 10:33 pm

by styrrell

The theory that Stages would cause you to favor one leg in trianing is just that, a theory. Find some foundation that it would happen and its worth debating.

Looking at the same theory everyone that swims regularly should have pretty good form as swimming with good form is easier. A quick look at a triathlon will show the theory doesn't always hold though.

by Weenie


mca56
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Joined: Mon Sep 25, 2006 1:16 pm

by mca56

DC Rainmaker posted "No Spring Release" for the Garmin Vector over on the Slowtwitch forum. Sounds like he has some inside information. I officially give up my multi-year wait for the Vectors as I need a new PM for this season. Oh well....

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djconnel
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by djconnel

styrrell wrote:The theory that Stages would cause you to favor one leg in trianing is just that, a theory. Find some foundation that it would happen and its worth debating.

Looking at the same theory everyone that swims regularly should have pretty good form as swimming with good form is easier. A quick look at a triathlon will show the theory doesn't always hold though.


Your swimming analogy isn't good because swimmers judge their effort based on speed, and the goal is speed, so they're working directly toward that goal. The most effective method to attain a target L-leg power is to pedal harder with your L leg. Consider a bike powered by hand and foot, but measured power only with feet -- you'd quickly realize using the hand pedals wasn't helping you get through your workouts, even if the hand pedals would help you go faster.

styrrell
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by styrrell

Consider a bike powered by hand and foot, but measured power only with feet -- you'd quickly realize using the hand pedals wasn't helping you get through your workouts, even if the hand pedals would help you go faster.

you keep saying this as if its fact.

rchung
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by rchung

styrrell wrote:The theory that Stages would cause you to favor one leg in trianing is just that, a theory. Find some foundation that it would happen and its worth debating.


Well, my foundation for that was the Tacx ergometer. As I pointed out above, this was before I had a Power Tap so all I could go by was the Tacx and my HR monitor. My "set wattage" workouts were easier to complete if I pedaled faster (for any given gear ratio). My heart rate was lower, and it felt better/easier. So for a long time I thought "Aha! Higher cadence at the same power = easier! I should keep my cadence high!" So I was performing high cadence low torque (and, unbeknonwst to me, low power) intervals and, when I went for outdoors rides (where I had neither the Tacx nor an on-bike power meter) I followed that lesson.

Now, of course, I know better -- because I have a much more accurate and precise power meter. But if I didn't, I might be trying to spin at 100+ rpm all the time. Cadence was a red herring.

So it's not unreasonable to think that some people would "ride to the numbers" and look for ways to maximize whatever the power meter was reporting. This, however, wasn't part of our review. Ray had taken this aspect of the comparison off the table.

styrrell
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by styrrell

I don't doubt that their are lots of cases where people ride to the numbers, but their being some cases doesn't prove that it happens in every case.

Aside from that in your case you were actively trying to ride to the number. You had to know your cadence was faster and you said you knew your HR was lower and it felt easier. All that would be true with stages if a rider uncliped the right leg, but I doubt anyone would do this, just because it maximizes the power.
Besides in your case you would still have speed PE, and HR that would be telling you that favoring one side isn't faster.

mentok
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by mentok

djconnel wrote:Stages has a separate issue, though, which is those with L-leg power versus those with 2-leg power at the end of the 12 weeks may have trained themselves to ride imbalanced to the left side, since the body tends to find the lazyist way to accomplish a goal, and if my goal is to see a certain number on my power meter, right-leg power isn't doing much to help me reach that number. Why waste effort?


and this is why i'm out. I was really interested in the stages and i can accept some of the limitations but this is the one that kills it. i know full well that my brain and body will figure out that i can get through a 30s/2min/5min/10min interval on the rollers at my target power much more easily by working the measured leg harder and neglecting the unmeasured leg. consciously or sub-consciously, it will happen eventually. it goes the other way too - if i'm pacing in a tt or a solo breakaway or something i will want to stick to my power target but i will soon figure out that i can go faster but still stay under the limit by working the non-measured leg more than the measured leg and i'll blow up. of this, i have no doubt and it even if the differences in leg effort are subtle and only in the order of a few percent then they're there, they're devaluing my training, they're messing with my races and thus the meter is a waste of time.

seriously, for a few hundred dollars extra, surely they could just slap another measuring cell on the other crank arm, do some processing and give me all the data but still remain at a reasonable pricepoint (ie similar to a quarq or p2m). hoping this is in the pipeline because then i'd be back on board...

mentok
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by mentok

styrrell wrote:I don't doubt that their are lots of cases where people ride to the numbers, but their being some cases doesn't prove that it happens in every case.


i ride to the numbers when i'm interval training and when i'm pacing. other than that, my powermeters are only for determining training stress (which i think the stages would probably do just fine) and for tracking progress (again, stages probably does this fine over time intervals of more than a few seconds). if you're not using the PM for intervals or pacing then although you're really not getting as much use out of it as you could, the stages would probably suit you just fine. If you are using your PM for intervals or pacing then spending the better part of $1k for something that may or may not be good enough when you could spend 1.5k to get something that definitely is good enough doesn't seem to be a great idea to most.

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djconnel
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by djconnel

mentok wrote:seriously, for a few hundred dollars extra, surely they could just slap another measuring cell on the other crank arm, do some processing and give me all the data but still remain at a reasonable pricepoint (ie similar to a quarq or p2m). hoping this is in the pipeline because then i'd be back on board...


Full agreement. There's some obvious engineering challenges, but the Pioneer unit does this. (I had to check my blogpost to remember the Pioneer... I haven't heard much about that since then.) I'd suggested this to Stages @ Interbike and the response I got was a guarded positive (the discussion was generally guarded).

Image

commfire
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by commfire

http://www.dcrainmaker.com/2013/02/upda ... ruary.html

Supposedly Garmin has not given up yet.

Epic-o
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by Epic-o

mentok wrote:seriously, for a few hundred dollars extra, surely they could just slap another measuring cell on the other crank arm, do some processing and give me all the data but still remain at a reasonable pricepoint (ie similar to a quarq or p2m). hoping this is in the pipeline because then i'd be back on board...


They should first find a way to measure cadence properly. This happens when you develop your product using stationary bikes

claus
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by claus

Does anyone have more information about the power pedals from Australia? They seem to offer the most functionality, i.e., they would make a nice toy to have.
Maybe they will be available before the Vector?

claus
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by claus

For those who understand German:
the German triathlon magazinehas a test of various power meters, including Rotor Power.
The article is available as PDF.

The summary for Rotor power is (rough translation):
There are still problems calculating the forces.
The graphs show from the very beginning more noise which amplifies for the duration of the test.
However, the manufacturer should be able to solve this problem with growing experience.

medium deviation: +6.1%
maximum deviation: +9.9%

erty65
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by erty65

claus wrote:For those who understand German:
the German triathlon magazinehas a test of various power meters
http://www.srm.de/index.php/gb/srm-blog/triathlon-blog/775

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prendrefeu
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by prendrefeu

I did not read the article in full yet and I plan to later today, but on initial glance it's interesting that the mag posted no accuracy readings nor variance for the PowerTap G3. Anyone know why?
Exp001 || Other projects in the works.

by Weenie


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