WTD: Someone with Power Meter to help calibrate my trainer

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T.M.H.N.E.T
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby T.M.H.N.E.T » Wed Oct 24, 2012 15:45 pm

After all the preaching about innaccuracies,it's only now when directly asked for your experiences,you don't want to talk.

Funny old world isn't it.

Trev The Rev
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Trev The Rev » Wed Oct 24, 2012 15:58 pm

T.M.H.N.E.T wrote:After all the preaching about innaccuracies,it's only now when directly asked for your experiences,you don't want to talk.

Funny old world isn't it.


Torque tubes, intermittent data, no data, inaccurate readings, re calibrating by manufacturer, I had no problems when testing Garmin Vector (but they were limited tests and were pulled before delivery) and no problems with Wattbike. I have not used SRM personally so can't speak for them.

ziglar
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby ziglar » Wed Oct 24, 2012 17:32 pm

they all us string guage technology so without being overly technical what is it about the Vector that presented less (or no) problems? Is part of it that the pedal based solutions use some kind of direct force measurement (i.e. pressure on sensor) whereas the others use some kind of deflection or shear force measure?

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Alex_Simmons/RST
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Alex_Simmons/RST » Wed Oct 24, 2012 21:13 pm

Trev The Rev wrote:
Alex_Simmons/RST wrote:
Trev The Rev wrote:What, power meters not accurate and need calibrating, you will be saying there are fairies at the bottom of the garden next. All that power meter data analysis might be wrong because the power meter might not necessarily be calibrated correctly, good god man, this could lead people to need counselling.

Are you banned from the TTF or something? :lol:


Yes, partly due to complaints by people trying to sell power meters, they get a bit touchy whenever I point out how many threads there are on timetrialling forum about power meters that don't work properly.

Well, for what it's worth, it sure wasn't me and banning you is dumb.

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Alex_Simmons/RST
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Alex_Simmons/RST » Wed Oct 24, 2012 21:26 pm

Team4Luke wrote:
Alex_Simmons/RST wrote:Speed on a trainer is meaningless. All that matters is intensity and time.



not neccessarily, depends on the trainer and whether you run a permanent bike and permanent conditions
<snip>
Doesn't take much to set up a fixed rig, you only need bare minimum of a whole bike, second hand bits, proper turbo tyre and should be no need to move it ever and should get easily a year out of a tyre if not more.

Oh, been there, done that...

Image

My point is that:

i. for those who don't have all those variables sorted, then speed - power relationships will be highly variable, and so speed as a proxy for power has a resolution less than the typical level of intra season fitness change.

ii. for those that do, then speed does not reflect outdoor riding speeds. It can't for the simple reason that outdoors we have a ton of variables in play.

the only units that can reasonably replicate outdoor speeds are those that have a programmable resistance, and have a load unit that's accurate and enables calibration.

So, we get back to the basic premise of training: measurement of time (easy) and intensity (problematic).

With regard to intensity, a high degree of precision isn't absolutely necessary for training (hence we can "get away with" things like RPE) - however precision is required if you are attempting to assess changes in fitness, or whether such training is having the desired impact.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Alex_Simmons/RST » Wed Oct 24, 2012 21:48 pm

Trev The Rev wrote:Or what it is supposed to do but does not most of the time.

Trev, power meters work reliably most of the time. Like all technologies, sometimes they don't, and some brands / models have been more problematic that others. But broad sweeping statements like these are disingenuous.

People rarely decide to pop onto an online space and report that their power meter worked as advertised today. If they did, we would be overwhelmed by such messages to the extent that those people reporting something unusual would be hard to find.

The people that are most critical of power meters are in fact the hard nosed long term users of power meter technology - but they do so with the benefit of both a strong understanding of the technology, and on the basis of actual issues/numbers. I can assure you that I am a very tough marker of PM manufacturers, but I am not alone.

You are basing your views on a biased sample, and quite possibly an inherit bias with respect to such technology to start with. That's not to say that I don't have bias myself, but I use a critical thinking approach that at least attempts to address or remove such biases before drawing any conclusions.


The other part of your argument is often directed to ease of use. Yes, it is important that users learn a bit about their new meter, and how to use it properly. That includes knowing about setting torque zero, understanding calibration checking, and correct set up of the computer device used to record/display the data.

These are matters that all well covered in the public domain and/or power meter reference materials. I hardly think it is the fault of the equipment if someone does not take the time to learn how to use it properly. The makers of the technology do try hard to makes things as user friendly / simple as possible. Some are better at it that others.

But statements like yours are simply not based in evidence.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Trev The Rev » Thu Oct 25, 2012 08:30 am

Alex_Simmons/RST wrote:
Trev The Rev wrote:Or what it is supposed to do but does not most of the time.

Trev, power meters work reliably most of the time. Like all technologies, sometimes they don't, and some brands / models have been more problematic that others. But broad sweeping statements like these are disingenuous.

People rarely decide to pop onto an online space and report that their power meter worked as advertised today. If they did, we would be overwhelmed by such messages to the extent that those people reporting something unusual would be hard to find.

The people that are most critical of power meters are in fact the hard nosed long term users of power meter technology - but they do so with the benefit of both a strong understanding of the technology, and on the basis of actual issues/numbers. I can assure you that I am a very tough marker of PM manufacturers, but I am not alone.

You are basing your views on a biased sample, and quite possibly an inherit bias with respect to such technology to start with. That's not to say that I don't have bias myself, but I use a critical thinking approach that at least attempts to address or remove such biases before drawing any conclusions.


The other part of your argument is often directed to ease of use. Yes, it is important that users learn a bit about their new meter, and how to use it properly. That includes knowing about setting torque zero, understanding calibration checking, and correct set up of the computer device used to record/display the data.

These are matters that all well covered in the public domain and/or power meter reference materials. I hardly think it is the fault of the equipment if someone does not take the time to learn how to use it properly. The makers of the technology do try hard to makes things as user friendly / simple as possible. Some are better at it that others.

But statements like yours are simply not based in evidence.


Alex,

My comments are based on my personal experience and on those of people I have spoken to, both users and trade.
I understand that power meters need to be used correctly and properly calibrated.

The point I am making us that unlike a Concept 2 Rower or Wattbike which measure power accurately and reliably and require no calibration or regular maintenance other than to hoover away too much dust, cycle power meters, due to the fact they must work on a moving machine outdoors and must weigh very little, have to use different technology which is not as robust.

In my opinion cycle power meters need a certain level of technical understanding, ability and also time, to be used correctly. Even then there is a good chance it will have to be returned to the manufacturer / supplier at some point.

However, if purchased from a specialist who can provide back up and help, and by specialist I do not mean any old bike shop or bloke on the internet who can supply, but a 'specialist' such as yourself, then a power meter is an extremely valuable tool for the sort of rider who has the right sort of mindset to use it properly or a rider with a coach who can make sure he is operating the power meter correctly.

Although I agree with you entirely that the best way to train scientifically is with a power meter I think there is a tendency to forget that it is very possible to train scientifically and effectively without a power meter.

All said, I would recommend a power meter to anyone provided they purchase through a specialist or if they are certain they have the technical ability to calibrate and maintain it correctly.

For what it is worth I have the greatest of respect for you as a coach and 'power meter expert' even though I might not agree with everything you say.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby amaferanga » Thu Oct 25, 2012 09:04 am

Trev The Rev wrote:The point I am making us that unlike a Concept 2 Rower or Wattbike which measure power accurately and reliably and require no calibration or regular maintenance other than to hoover away too much dust, cycle power meters, due to the fact they must work on a moving machine outdoors and must weigh very little, have to use different technology which is not as robust.


And?

Trev The Rev wrote:In my opinion cycle power meters need a certain level of technical understanding, ability and also time, to be used correctly. Even then there is a good chance it will have to be returned to the manufacturer / supplier at some point.


Welcome to the 21st century.

Trev The Rev wrote:However, if purchased from a specialist who can provide back up and help, and by specialist I do not mean any old bike shop or bloke on the internet who can supply, but a 'specialist' such as yourself, then a power meter is an extremely valuable tool for the sort of rider who has the right sort of mindset to use it properly or a rider with a coach who can make sure he is operating the power meter correctly.


Why? For warranty or technical issues can't you just deal direct with the manufacturer/importer? Why do you need a middle man?

Trev The Rev wrote:Although I agree with you entirely that the best way to train scientifically is with a power meter I think there is a tendency to forget that it is very possible to train scientifically and effectively without a power meter.


Is there? Or is that just a position you've decided to take to start a debate?

Trev The Rev wrote:All said, I would recommend a power meter to anyone provided they purchase through a specialist or if they are certain they have the technical ability to calibrate and maintain it correctly.


So now you think everyone should have a power meter. Hmmmm. What about all the problems you've had with every make of power meter? Don't these issues make them all but unusable?
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Trev The Rev » Thu Oct 25, 2012 09:17 am

I think you should buy from a specialist because then if you have problems, or need help or advice, most problems can be sorted without returning the power meter to the manufacturer. In my experience dealing with the distributors of Quarq, Look Keo Power (Fisher) and Powertap (Paligap) is a nightmare.

Most manufacturers only supply trade anyway.
Last edited by Trev The Rev on Thu Oct 25, 2012 09:26 am, edited 1 time in total.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby neeb » Thu Oct 25, 2012 09:21 am

As someone who recently bought a power meter for the first time (powertap G3), and also has several years experience of using a tacx trainer with power readings (Fortius), I can perhaps provide a case study in how easy or otherwise it is for a reasonably committed non-expert to get useful service out of one.

It did take me a few weeks to learn what the standard pitfalls are and how to deal with them, but all this information was fairly easily available in the manufacturer's documentation or on the web. I initially made the mistake of not including zero readings in the power recording and using autostop etc. It also took me a while to pick up on the importance of zeroing the meter. It wasn't rocket science however, and I would say that anyone who is reasonably concerned about getting reliable data would find out these things fairly quickly, i.e. if the reason you have bought a powermeter is to train seriously with it, you are likely to be able to learn to use it properly fairly quickly. Obviously if you have just bought it as an expensive accessory, there is no particular reason why you would end up learning how to use it properly...

As regards comparison with the tacx trainer power readings, a massive eye-opener for me has been discovering how inconsistent the tacx readings are during the progression of a training session, especially if high resistance is involved. Yes, if you set the roller resistance and tyre pressure precisely before each ride you can get pretty consistent average power values from one ride to the next (although they might be consistently 5 or 10% too high). The problem is that even after a substantial warm-up, the power readings continuously increase for at least 20mins for a given real power output, especially on a simulated climb. I did a session yesterday where the powertap told me I was putting out exactly the same average wattage for each of two 20min efforts, but the tacx fortius readings suggested that I had put out about 20w more on average during the second session! If you compare the graphs, you can see that the fortius power line slopes continuously upwards during the first session as the unit warms up due to the high effort and high resistance. The only way to deal with this would be to "warm up" the unit by doing a very tiring dummy interval session before you started the real one! I realise now that the reason my sessions on the fortius were always so knackering before I got the powertap was that I was always going far too hard to begin with to try to maintain what appeared to be a constant power output..

So far (fingers crossed) I have had no reliability issues with my PT and it seems to be doing what it says on the box.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby amaferanga » Thu Oct 25, 2012 09:36 am

Trev The Rev wrote:I think you should buy from a specialist because then if you have problems, or need help or advice, most problems can be sorted without returning the power meter to the manufacturer. In my experience dealing with the distributors of Quarq, Look Keo Power (Fisher) and Powertap (Paligap) is a nightmare.

Most manufacturers only supply trade anyway.


You can get advice then, but any actual problems won't be sorted by the retailer. My experience with Paligap is not good either, but so far my dealings with Power2max have been excellent.
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Alex_Simmons/RST » Thu Oct 25, 2012 09:40 am

Trev The Rev wrote:I think you should buy from a specialist because then if you have problems, or need help or advice, most problems can be sorted without returning the power meter to the manufacturer. In my experience dealing with the distributors of Quarq, Look Keo Power (Fisher) and Powertap (Paligap) is a nightmare.

Most manufacturers only supply trade anyway.

While I do provide such assistance and advice to my customers, in terms of warranty/service support, I am happy to deal with SRM Oceania or Quarq distributor or Quarq on behalf on my customers, or they can deal directly, it doesn't matter. Quarq have been excellent in providing backup and service support, as have the guys at SRM Oceania, when it's been needed.

Both Quarq and SRM do like it when I do this though, as it provides them with some assurance that the obvious issues have been checked and the customer is well informed.

I can't speak for the UK experience with distributors there, except for Bob Tobin at cyclepowermeters.com who's always been great when I've dealt with him (disclosure - we do have a joint arrangement by offering free training plans to his customers).

I think it's reasonable not to think of a power meter as a simple commodity item, however they are not that hard to use.

In terms of what you do with the information a power meter provides, well that's a totally different issue. Makers of power saws provide info on how the saw operates, but they don't teach you how to make a pergola, and nor should they be expected to.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Trev The Rev » Thu Oct 25, 2012 09:51 am

amaferanga wrote:So now you think everyone should have a power meter. Hmmmm. What about all the problems you've had with every make of power meter? Don't these issues make them all but unusable?


I think this here is a good example of the problems people might have with a power meter.

http://www.timetriallingforum.co.uk/ind ... try1029810

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby springtide9 » Thu Oct 25, 2012 12:03 pm

Trev The Rev wrote:
amaferanga wrote:So now you think everyone should have a power meter. Hmmmm. What about all the problems you've had with every make of power meter? Don't these issues make them all but unusable?


I think this here is a good example of the problems people might have with a power meter.

http://www.timetriallingforum.co.uk/ind ... try1029810


It appears that a good clean resolved the issues with the PM and it was suspected that the issue was likely related to the position of the magnet or similar. For what it's worth, I've had similar issues with the Garmin GSC-10 speed/cadence sensor and the magnet.
I would also assume that any speed/cadence sensor that uses a magnet is also prone to this type of issue, although I wouldn't completely rule out any device that uses a magnet.

And to put another side to the reliability, people generally post looking for help.... so looking at internet forums with regards to assessing reliability, probably is going to give an inaccurate opinion.
I understand you have been involved directly with the various products, so I'm not taking this knowledge away from you.

It would be interesting to know how many people on this forum are using PM's, and out of those people, how many people have had problems.

From personal knowledge, the Powertap service centre for the UK isn't very big. I'm not sure how many PT are sold in the UK, but I saw the PT boxes waiting for repair; they obviously do not have that many returns/repairs.
Last edited by springtide9 on Thu Oct 25, 2012 12:22 pm, edited 3 times in total.
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby amaferanga » Thu Oct 25, 2012 12:16 pm

Trev The Rev wrote:
amaferanga wrote:So now you think everyone should have a power meter. Hmmmm. What about all the problems you've had with every make of power meter? Don't these issues make them all but unusable?


I think this here is a good example of the problems people might have with a power meter.

http://www.timetriallingforum.co.uk/ind ... try1029810


Right. And for every user that has that problem there are thousands that don't.
Last edited by amaferanga on Thu Oct 25, 2012 13:03 pm, edited 2 times in total.
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Trev The Rev » Thu Oct 25, 2012 12:36 pm

amaferanga wrote:
Trev The Rev wrote:
amaferanga wrote:So now you think everyone should have a power meter. Hmmmm. What about all the problems you've had with every make of power meter? Don't these issues make them all but unusable?


I think this here is a good example of the problems people might have with a power meter.

http://www.timetriallingforum.co.uk/ind ... try1029810


Right. And for every user that has that problem there are thousands that don't.


That is only one problem, do not pretend only one power meter owner in a thousand has a problem. Go on a few forums and read all the problems people have.

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Re: WTD: Someone with Power Meter to help calibrate my train

Postby springtide9 » Thu Oct 25, 2012 12:58 pm

Trev The Rev wrote:
That is only one problem, do not pretend only one power meter owner in a thousand has a problem. Go on a few forums and read all the problems people have.


Google.... "shimano ultegra di2 problems"

In fact, google "<random technology> problems"

And you'll get a similar (high) number of results :D

As stated above, I'm not sure how many Powertaps have been sold in the UK, but looking at the size of the "PT service centre", I would conclude they are very reliable.
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby amaferanga » Thu Oct 25, 2012 12:59 pm

Trev The Rev wrote:
amaferanga wrote:
Trev The Rev wrote:
amaferanga wrote:So now you think everyone should have a power meter. Hmmmm. What about all the problems you've had with every make of power meter? Don't these issues make them all but unusable?


I think this here is a good example of the problems people might have with a power meter.

http://www.timetriallingforum.co.uk/ind ... try1029810


Right. And for every user that has that problem there are thousands that don't.


That is only one problem, do not pretend only one power meter owner in a thousand has a problem. Go on a few forums and read all the problems people have.


My views are mostly based on my own experiences, not what I read on an internet forum.

Also, no-one is claiming they never go wrong or that they're fit for fools so who are you actually debating your point with?
Last edited by amaferanga on Thu Oct 25, 2012 13:04 pm, edited 1 time in total.
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby amaferanga » Thu Oct 25, 2012 13:01 pm

springtide9 wrote:
Trev The Rev wrote:
That is only one problem, do not pretend only one power meter owner in a thousand has a problem. Go on a few forums and read all the problems people have.


Google.... "shimano ultegra di2 problems"

In fact, google "<random technology> problems"

And you'll get a similar (high) number of results :D

As stated above, I'm not sure how many Powertaps have been sold in the UK, but looking at the size of the "PT service centre", I would conclude they are very reliable.


PowerTaps are reliable until the torque tube fails. That's good in a way - they work or they're goosed so not usually any grey area.
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Re: WTD: Someone with Power Meter to help calibrate my train

Postby Trev The Rev » Thu Oct 25, 2012 13:17 pm

amaferanga wrote:
My views are mostly based on my own experiences, not what I read on an internet forum.


So are mine, which is why so many people on internet forums dislike me. The vast majority of people on internet forums have a herd like mentality and agree with the view of the majority of the people on the forum, even though the forum is usually a minority who have forgotten how few of them there really are.

Cyclists are a minority, time triallists a smaller minority, power meter users an even smaller minority and people who sell power meters one of the smallest minorities on earth.


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