The data from the review between quart and PT was pretty crappy too. +/-20 watts or so. But looking at the min/max deviations doesn't tell the whole story. I don't use a power meter so I can't really comment on how this affects the actual usage for training.

djconnel, good catch on the LeMond trainer data, I didn't make that connection !!!

Do you have any idea why the shifting would effect the data? It really can't be the vibrations or the Stages PM wouldn't never work right.

C

Stages responded page 4 of this thread.. Reasonable answers on some of the questions and some questions they can't answer this quick... ( got to love the "internet" ) I think this is going to very interesting to see how it plays out....

http://forums.roadbikereview.com/compon ... 803-4.html

C

Stages' response is far from reasonable. They claim they see good agreement, but show no data. In contrast, Ray did some excellent data analysis both on the trainer and on the road, providing an excellent power reference in the LeMond trainer (which should at least produce constant power @ constant speed, even if the power estimate it provides has a speed-dependent offset), and verifying his analysis with Robert Chung and Tom Anhalt, both of whom have been analyzing power data for many years and know what they're doing. It's well documented L-R balance is variable. Data from Polar/Look, from Vector prototypes, and from the literature all confirm this. Rainmaker's results were very much expected.

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Yep, they are basically saying: "Just wait, we have some more favorable reviews from 'testers' in our pocket coming out shortly".

I don't understand how they didn't see these problems in product testing? If you screw up transitions in cadence, you're going to screw up the power reading for that time point.

If it were only in the outdoor riders, you couple almost forgive them. But the Lemond comparison is really telling.

The hollowgrams are now available... And they're the most expensive units.

Geez they claim they want to bring an affordable PM to cyclists, don't they know most of us have CAAD10s with hollowgrams??

Sure they did. They're a small company though and this is their first product, right? Their choice was either to go to market and hope for the best, or declare bankruptcy.

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Sorry to say this but I did not do things right when I weighed the crank - who knows what I was thinking.

508 is the weight for the drive side only not including the axle - see here for more images.

http://www.flickr.com/photos/glorycycle ... 415464290/

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so are the stages shipping units yet? any word from users in the real world?

edit: @djconnell, I just read your post over at RBR - hadn't thought of issues relating to power issues occurring when cadence issues occur but you're exactly right. i get the sense that an accelerometer based cadence sensor would not be that hard to confuse (similar to the "cadence" sensor in a powertap i would imagine).

somewhat related - i wonder how power accuracy is affected by 1 Vs 2 or more reed switches for cadence, or whether a full-on encoder to give real time crank position and velocity would provide any real-world benefits...

We are doing our own testing. Our data looks a bit different. To be honest, ours looks better, and thanks to Chung and Anhalt's work we know what specific abnormality to look for (although we are also looking for others, or course). Will be a little while before we feel comfortable publishing anything, though.

Rainmaker does truly excellent work, but in this case I think it would have been worth trying additional units, and maybe another set of legs. Quite the death sentence to pronounce based on a single unit. It's possible that either our unit is better (it has brand new firmware) or my legs are more even (previous testing has indicated I'm within about 1.5% left to right, even well into a LT test.)

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Two wouldn't help much, since pedaling 2-legged, there's surges in torque for each leg, and in low-inertial situations that can cause accelerations (cadence increases) twice per pedal stroke. Now 4 magnets... that would be nice.

Still, I think fully electronic cadence is better. VNTech: why no gyroscopes? Too much power?

On L-R balance: here's a reference.

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They are shipping now but some models will be a awhile. Their facebook page has a bunch of info. I ordered the SISL2 and it won't ship till late April at the earliest.

I put about 12k miles on my quarq last year and have a little less than 2k miles riding on both a stages unit (I was lucky enough to get early) along with the quarq. Anecdotal, but at this point I feel the Stages unit is as consistent as the quarq.

As far as riding, I've been doing a mix of intervals, hill repeats, steady efforts and some groups rides which are all over the place. I generally watch 3sec and 30sec power and then compare avg power at the end of the ride.

Since this is WW.

Stages rival left + red right and rival rings (53/39): 712.5g
Quarq with TT/Red rings (54/39): 840.7g

175 Rival arm no PM: 217g
175 Rival arm with PM: 231.6g

Stages crank arms are already shipping - Yea!

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what does everybody think of this? from Neal Henderson twitter

Neal Henderson ‏@nealhenderson
And my SRM with 2 different head units on at same time and found typical variations of 2-4% for 1 powermeter broadcasting to 2 head units.


kinda means that nothing is going to be "good" : (

C