Power meter question

[Willy]

I am looking at buying a Stages left side power meter for my Dura-Ace setup because it looks very easy to install and seems to work. Question - I am stronger on my right side so the readings might not be correct for me but if the purpose of the meter is to compare power for each ride, does it matter if I don’t have the correct overall reading?

[nooneline]

Power meters vary in accuracy - they vary model to model, and within models. By fairly small amounts, but still.


So the fact that yours might not have a fully 'accurate' read within what i'd assume is a few percentage points based on your discrepancy is more or less within the bounds of PM variance.

And you're correct - the point of having a PM is to compare like data to like data. it might not be the exact correct number of watts, but the inaccuracy will be the same ride to ride.

[Joxster]

I am looking at buying a Stages left side power meter for my Dura-Ace setup because it looks very easy to install and seems to work. Question - I am stronger on my right side so the readings might not be correct for me but if the purpose of the meter is to compare power for each ride, does it matter if I don’t have the correct overall reading?

As long as you use the same PM for everything then it's ok, but if you swap around then the readings will be irrelavent as they will be different. Personally I would wait till easter and get the new SRMs that register on both cranks.

[false_Aest]

For normal people it doesn't really matter. Consistency in measurement + testing protocol is more important.

You could be putting out 300 zippies using a left side meter on a ramp test.
I could be putting out 100 bananas using a right side meter on a 2x8min test.
11.4 could be putting out 700 watts using a dual-sided meter on 20 min test

So long as the measuring device is consistent and so long as you use the same protocol to test then you're good.

So if 11.4 uses my meter on a 20 minute test his bananas are not going to match his watts.
If I do a ramp test with my meter, my bananas will not be the same as the bananas I get with a 2x8 test.

yadda yadda.

[echappist]

I am looking at buying a Stages left side power meter for my Dura-Ace setup because it looks very easy to install and seems to work. Question - I am stronger on my right side so the readings might not be correct for me but if the purpose of the meter is to compare power for each ride, does it matter if I don’t have the correct overall reading?

it does

for people without significant discrepancy, general trend is that one leg "slacks off" for efforts sub-threshold, but the two legs even out for harder efforts

if you already have a leg that's stronger, no telling exactly how this varies as a function of intensity

whether this makes any difference to you is your own call

[John H.]

What are you going to use it for?
Do you care about the numbers, what they mean, how they compare, etc.?
Or do you just want some basic power information to go along with your rides?
Will use use the Stages for intervals? During the intervals do you care how good the power information that you see is?

I ask this because I used a single sided Stages for several months.
The overall power data and kj numbers were pretty accurate.
But it was terrible if you wanted to use the data to hit specific numbers on the bike.
Readings come out of the Stages in a very up/down fashion- Even when you are riding very steady. 220-270-200-300- etc. Then a signal drop where the power drops like a rock- Very hard to follow. But like I said, the end of the day data was not far off- So depends on what you want.

[nooneline]

Readings come out of the Stages in a very up/down fashion- Even when you are riding very steady. 220-270-200-300- etc.

This is how all PMs work - by sampling your output, which varies significantly. When enough data averages out, you get accurate reads.

[John H.]

The stages is worse than any other powermeter I have used in this regard.
Even when using 3 second average rather than actual power.
I have used SRM, Quarq, and Power2max- All work a lot better than a Stages.

This is how all PMs work - by sampling your output, which varies significantly. When enough data averages out, you get accurate reads.

[GParkes]

So how do you know your right side (leg) is stronger than your left? Have you tested them during a pedal stroke (as opposed to pushing a machine in a gym)? I always thought my right side was stronger because I'm right handed/footed. Went from a single sided crank based PM to dual sided Powertap pedals. Work out the other night power balance was 49.2/50.8 - L/R. Kinda hard to say my right side is "stronger". Maybe more efficient?

[glepore]

I have 3 stages (gen 1,2,3) 2 quarq’s, and have had srms in the past. For my purposes they are functional equivalents. The stages isn’t as responsive for instantaneous efforts, which would matter if you’re training for 3-4 second bursts but I don’t know of anyone that does that. Stages had water intrusion issues that have been resolved. I’ve read the reports of dropouts but not experienced it, perhaps because I have smaller frames and use a Bolt.


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[BdaGhisallo]

Personally I would wait till easter and get the new SRMs that register on both cranks.


Oh? Do tell. I haven't heard anything of this. What do you know?

[Joxster]

Oh? Do tell. I haven't heard anything of this. What do you know?

Was over at the factory and saw the prototypes, Caja Royal have been using them this season

And it won't let me post a picture..........

[kramnnim]

The latest Fast Talk podcast from Velonews goes over the disadvantages of single sided power meters.

[R3awak3n]

For normal people it doesn't really matter. Consistency in measurement + testing protocol is more important.

You could be putting out 300 zippies using a left side meter on a ramp test.
I could be putting out 100 bananas using a right side meter on a 2x8min test.
11.4 could be putting out 700 watts using a dual-sided meter on 20 min test

So long as the measuring device is consistent and so long as you use the same protocol to test then you're good.

So if 11.4 uses my meter on a 20 minute test his bananas are not going to match his watts.
If I do a ramp test with my meter, my bananas will not be the same as the bananas I get with a 2x8 test.

yadda yadda.

this is my opinion as well. As a training tool and if you always use that same PM it does not really matter. So what if its your non dominant weaker leg, if your power at the end of the season is 300 from 250 start of the season then that is that.