Stages Power Meter

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Re: Stages Power Meter

Postby boss » Mon Nov 11, 2013 9:40 am

Alex Simmons/RST wrote:
singlespeedscott wrote:I don't really understand the benefits of using a PM on a MTB. The surfaces and conditions are constantly changing and I would think that trying to maintain a certain wattage would be next to impossible. On the road everything is more consistent which would make it better for training and racing.

The applied use of power meter data is far broader than what you happen to be doing at any particular instant.


+1

Power isn't just about real-time pacing.
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by BNA » Mon Nov 11, 2013 2:37 pm

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Re: Stages Power Meter

Postby btothec » Mon Nov 11, 2013 2:37 pm

I've had my XTR M980 crank on my MTB coming up on 2 weeks now. Ended up cancelling my US order through PriceUSA as it was going to be a 3 week wait for them to get the crank delivered from stages to their rep in America then plus delivery time to Australia. So I ended up ordering it through Cycling Galleria in Melbourne. Ordered it on a Thursday and had it on my bike 2 days later.
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Re: Stages Power Meter

Postby AUbicycles » Mon Nov 11, 2013 8:43 pm

Alex Simmons/RST wrote:I'd say the following is more accurate:
power meters are more accessible to a bigger number of bikers


I accept this.
The difference with Mountain bikers is that they havn't looked towards power in the same way as roadies and track cyclists.
Currently Stages are selling internationally roughly 80% to roadies and 20% to MTBers and I find the 20% astounding.

Here is a First Look at Stages.
http://www.bicycles.net.au/2013/11/data ... wer-meter/
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Re: Stages Power Meter

Postby Alex Simmons/RST » Mon Nov 11, 2013 9:23 pm

AUbicycles wrote:
Alex Simmons/RST wrote:I'd say the following is more accurate:
power meters are more accessible to a bigger number of bikers


I accept this.
The difference with Mountain bikers is that they havn't looked towards power in the same way as roadies and track cyclists.
Currently Stages are selling internationally roughly 80% to roadies and 20% to MTBers and I find the 20% astounding.

Here is a First Look at Stages.
http://www.bicycles.net.au/2013/11/data ... wer-meter/


This comment intrigued me:

Pat Warner provides a glimpse into the new reality that power can offer “You can start seeing what kind of aerodynamic differences you are going to have from wheel to wheel or from skin suit to skin suit. It’s been an interesting progression from ‘Power was only for your body’ now you can start to make equipment selection.”


As an expert in the use of power meter data for this very purpose, I can tell you right now that the data from a Stages is inadequate for this task, and it's misleading to present it as such.

You can believe in data all you like, but you also need to know the limitations of the data you have.

As for comparisons with other meters, whilst I thoroughly recommend DC Rainmaker's reviews, not testing products against the only meter to have been thoroughly assessed in the scientific literature is, IMO, a flaw.
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Re: Stages Power Meter

Postby AUbicycles » Tue Nov 12, 2013 11:33 am

Pat commented on the broader implications of Power and how data can be used. If it is important, I can get a bigger sound-byte for you.

With DC Rainmaker - if he has four power meters running I find this very telling when the power meter data lines-up across the board and you can see when, where and why there is variation. Would a power meter that has been assessed by a scientific journal reveal surprisingly different results in this context?

I think the key for Stages in comparison with other power meters is who it is designed for - yes it does compete with other power meters. Each have their pros and cons and I am certain that if you need specific data then you should chose the technology that will allow you to get this. Your needs as a coach and a high-level athlete will be different, or more advanced than many others.

This is what Slowtitch had to say

Who is going to use all that data, anyhow?

I hear you. Even if we could calculate, send, and record power super-duper fast, would it be useful? Do we NEED more than once-per-second? Probably not. At least for triathlon, we’re generally dealing with large pieces of time for our rides and races. If you did a four hour training ride, you probably won’t analyze a segment less than five minutes in length. When that is the case, receiving data every second is probably enough. The case where super-fine analysis is useful is in shorter cycling races. If you’re doing a 100 meter sprint on the velodrome, you might want to look at half or quarter-second power data. Go nuts. Just know that what you need for this is faster events (and calculations of power).
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Re: Stages Power Meter

Postby boss » Tue Nov 12, 2013 11:45 am

I think its simply horses for courses when picking a PM.

I know people cite DC as proof that Stages are the real deal... then you get some guy comes in and counters with n=1... but Alex - have you worked with a Stages as yet?
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Re: Stages Power Meter

Postby Alex Simmons/RST » Tue Nov 12, 2013 12:40 pm

AUbicycles wrote:Pat commented on the broader implications of Power and how data can be used. If it is important, I can get a bigger sound-byte for you.

With DC Rainmaker - if he has four power meters running I find this very telling when the power meter data lines-up across the board and you can see when, where and why there is variation. Would a power meter that has been assessed by a scientific journal reveal surprisingly different results in this context?

I think the key for Stages in comparison with other power meters is who it is designed for - yes it does compete with other power meters. Each have their pros and cons and I am certain that if you need specific data then you should chose the technology that will allow you to get this. Your needs as a coach and a high-level athlete will be different, or more advanced than many others.

This is what Slowtitch had to say

Who is going to use all that data, anyhow?

I hear you. Even if we could calculate, send, and record power super-duper fast, would it be useful? Do we NEED more than once-per-second? Probably not. At least for triathlon, we’re generally dealing with large pieces of time for our rides and races. If you did a four hour training ride, you probably won’t analyze a segment less than five minutes in length. When that is the case, receiving data every second is probably enough. The case where super-fine analysis is useful is in shorter cycling races. If you’re doing a 100 meter sprint on the velodrome, you might want to look at half or quarter-second power data. Go nuts. Just know that what you need for this is faster events (and calculations of power).


OK, I mistakenly inferred that quoting someone from Stages speaking about using power meters for aerodynamic analysis in a thread about Stages power meter meant they implied the Stages was suitable for such a purpose.

When it comes to the quality of power meter data the devil is in the detail, and I'm afraid the cycling population at large is not well informed about such things. Even in the slowtwitch item linked above, there are some things about ANT+ data capture that have profound impact on the reliability of what's reported (not specifically related to Stages), and were unreported in that item.

In any case, my statement about such things and my considered view on Stages (and all the available power meters) are summarised in this item I wrote in August:
Which Power Meter?

Stages

Stages has taken a different approach with its left crank arm based power meter introduced at Interbike in Spetember 2012. Model options are limited to aluminium crank arms only but there is a good choice of Shimano, SRAM and Cannondale crank arms, so that may or may not be a restriction for some people, although it's still a decent range of options. Carbon crank lovers will need to look elsewhere for their power meter.

Stages is one of the lower cost options of the direct force / strain gauge power meters available, and on that front alone has quite an appeal for those unwilling or unable to spend more. It's compatible with ANT+ power enabled cycle-computers as well as bluetooth enabled devices. It would seem to be a pretty easy meter to use, and update of firmware not an overly difficult process.

Again it's still early days, and with permanent accuracy caveat due to Stages assumption that total power is double the single left leg measurement means some restriction on high end useability of data, but for general training progression and overall workload tracking, as well as real time guidance on level of effort, it is likely to be fine, subject to reliability/durability considerations yet to really be tested. You are however unlikely to be able to use data from a Stages to reliably perform higher end analysis work, such as refinements in aerodynamics, or peak force-velocity testing. The single leg measurement by its very nature makes it unsuitable for such applications.

Keep in mind that sales distribution and back up is not in place yet in many parts of the world so if you are hanging out for one, you might need to be patient, or consider other options that are available.
http://www.stagescycling.com/stagespower
Review - dcrainmaker
Review - Bicycling.com
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Re: Stages Power Meter

Postby jasonc » Tue Nov 12, 2013 12:43 pm

Alex Simmons/RST wrote:but for general training progression and overall workload tracking, as well as real time guidance on level of effort, it is likely to be fine, subject to reliability/durability considerations yet to really be tested.


This comment is enough for me to really consider it as an option, especially when Chris gets me an eval unit :mrgreen:

can't blame a guy for trying
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Re: Stages Power Meter

Postby Alex Simmons/RST » Tue Nov 12, 2013 12:44 pm

boss wrote:I think its simply horses for courses when picking a PM.

I know people cite DC as proof that Stages are the real deal... then you get some guy comes in and counters with n=1... but Alex - have you worked with a Stages as yet?


None of my clients is at this time, although several have Vectors. I'm unlikely to ever use a Stages myself, considering that I ride with a prosthetic left leg.
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Re: Stages Power Meter

Postby Alex Simmons/RST » Tue Nov 12, 2013 12:52 pm

jasonc wrote:
Alex Simmons/RST wrote:but for general training progression and overall workload tracking, as well as real time guidance on level of effort, it is likely to be fine, subject to reliability/durability considerations yet to really be tested.


This comment is enough for me to really consider it as an option.


Indeed. And hopefully people can see that I am not negative about the product. All I seek to do is help people understand there are limitations with the data and what they are (all the meters have them).

People do often dismiss the importance of accuracy and precision for their needs, and that's fine. Just don't expect to do things in future that require such a level of data quality.
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Re: Stages Power Meter

Postby Alex Simmons/RST » Tue Nov 12, 2013 1:06 pm

AUbicycles wrote:Would a power meter that has been assessed by a scientific journal reveal surprisingly different results in this context?

It has in the past. And interestingly, it has also revealed flaws in the testing methodology used by one group of researchers who didn't even RTFM!

DCR does a great job, but we need to be pretty careful in interpreting this information which is looking at samples of one of each unit. It is also notoriously difficult to parse this stuff apart properly. DJConnell does a good job of this and Robert Chung has some elegant analysis methods as well.

Indeed it was one such analysis method that highlighted a sizeable problem with Stages rotational velocity data. Stages initial reaction was to attack the messenger and deny the problem. Except it was real, and Stages eventually had to address it and made a firmware update to fix it.

Claims about accuracy from many power meter companies are a bit loose and fast for my liking.
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Re: Stages Power Meter

Postby btothec » Thu Nov 14, 2013 3:18 pm

Alex I'm an RST client coached by Xavier. As I've mentioned in the thread I have a Stages crank arm on my MTB. If you want to have a look at some data to see what it's like I'm happy to send you through some files or you my even be able to access my uploads through the RST Podio website. Let me know if you do.

Ben.
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Postby Causidicus » Thu Nov 14, 2013 4:05 pm

Stages = good data for amateurs.

SRM/Powertap = data for professionals.

Stages is a nice addition to the market but not going to make me stray from SRM's reliability, accuracy and dependability.
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Re: Stages Power Meter

Postby Alex Simmons/RST » Thu Nov 14, 2013 4:14 pm

btothec wrote:Alex I'm an RST client coached by Xavier. As I've mentioned in the thread I have a Stages crank arm on my MTB. If you want to have a look at some data to see what it's like I'm happy to send you through some files or you my even be able to access my uploads through the RST Podio website. Let me know if you do.

Ben.

Ah, cool. :)

If you think there's a file worth looking at, you can alert me, although in isolation there's not a lot to really to comment on wrt how it compares with other meters

I had a quick look at one file, the power trace looks pretty much like most other power traces, which is what you'd expect.

Powertap power traces do have a different look due to the aliasing effect which makes the power data look a little more choppy than it actually is.

Other things to look for are any ghost power values, e.g. cadence = 0 when you stop pedalling, but a couple of repeat power values <>0.
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Re: Stages Power Meter

Postby Arlberg » Sun Nov 24, 2013 7:52 pm

I am wondering why the calibration number/reading on my unit continues to rise. When I first bought the Stages it calibrated at 900, now it's calibrating at 919. I thought it may have been due to the ambient temperature rising as we come into Summer but I took it to Thailand recently where it was way hotter than here and it calibrated at a lower number than it is calibrating at now. What influences the calibration reading and what would cause it to rise over time?
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Re: Stages Power Meter

Postby Roub » Sun Nov 24, 2013 8:32 pm

This week I successfully fitted a Stages crank arm across two bikes - road and mtb.

DuraAce road arm fits easily to the road bike, for the mtb I have moved the BB spacer to the other side and added 1.6mm of shimming. I also run a pedal washer on that arm.

Works a treat and data coming through is consistent with the trainer
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Re: Stages Power Meter

Postby X-ray » Thu Dec 12, 2013 6:53 am

I took my bike in yesterday for it's 3 month service at the LBS and upon setting off this morning for a ride I discovered that my Stages is no longer working :!:

I'm not sure what the problem is...it just won't register on my Garmin. It ain't a flat battery because that's the first thing I checked.

I'm taking the bike back this morning. They sell Stages so hopefully they'll have some clues. I can't really imagine that they could have broken it. Wait and see what they can tell me. :?

Has anyone else had similar issues??
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Re: Stages Power Meter

Postby joomz » Thu Dec 12, 2013 7:28 am

What a pain. I couldn't get my garmin to pick up my stages once. It was ok once I power cycled the garmin. Have you tried turning the garmin off and on again?
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Re: Stages Power Meter

Postby Carrots » Thu Dec 12, 2013 9:12 pm

X-ray wrote:I took my bike in yesterday for it's 3 month service at the LBS and upon setting off this morning for a ride I discovered that my Stages is no longer working :!:

I'm not sure what the problem is...it just won't register on my Garmin. It ain't a flat battery because that's the first thing I checked.

I'm taking the bike back this morning. They sell Stages so hopefully they'll have some clues. I can't really imagine that they could have broken it. Wait and see what they can tell me. :?

Has anyone else had similar issues??



They didn't wash your bike did they?
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Re: Stages Power Meter

Postby Lukeyboy » Thu Dec 12, 2013 9:36 pm

I was going to say the same thing.
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Re: Stages Power Meter

Postby Roub » Fri Dec 13, 2013 10:32 am

+1 on the washing comment. Check the battery compartment for moisture.

There are a few reports online of moisture ingress causing the battery to prematurely flat. Stages have been great and are working on a solution for affected devices. They are very frustrated over a 15cent part causing dramas for a $1k power meter
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Re: Stages Power Meter

Postby Xplora » Fri Dec 13, 2013 11:07 am

Will be eagerly keeping an eye on all this.
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Re: Stages Power Meter

Postby X-ray » Sun Dec 15, 2013 10:26 am

Thanks for the suggestions guys. :)

Turns out the problem was the battery - and a simple and slightly silly error on my part. :oops:

It was just a coincidence that the battery went flat during the service,making it look like something happened to the unit while it was at the shop. When I inserted the new battery initially, it wasn't contacting the positive electrode properly. It turns out you have to slide the battery in a the correct angle otherwise it won't sit correctly in it's holder. I found this out through trial and error. Once I had this sorted the unit sprung back to life :)

Anyway, so the Stages is working flawlessly again. And in case you were wondering, the battery lasted about 35 hrs.
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Re: Stages Power Meter

Postby jasonc » Sun Dec 15, 2013 5:35 pm

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Re: Stages Power Meter

Postby r11ss » Sun Dec 15, 2013 6:30 pm

I had the same problem, gave the bike a quick wash and the battery was flat 24 hours later. Saw a drop of water in the battery compartment too.
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