Thinking about getting PowerTapped up...

singlespeedexplosif

What's the gen?
Is there a big difference between Elite + and Pro +?
What's software compatibility like with Macs?
Will I rule the world?
Ta!

wastrel

I can only comment on the Mac bit - 'golden cheetah' software was the way to go for me and it works great - i got no joy at all with the software that came with it. That may just be me being incompetent though.

I got my wheel built by Steve at Wheelroom and I've ridden horrible cornish lanes and all over the pyrenees on it for a few months with no probs.

amaferanga

Elite+ is heavier.

What are you training for?

DaveyL

One thing I would add is that it helps if you are a bit geeky about logging and analysing your rides (using either Golden Cheetah or WKO+ which you can get to work on a Mac I think. I am still not impressed with the latest version of PowerAgent, the software you get with the PT).

To get the most out of the powermeter you need to use it on as many of your rides as possible (at least until you are able to produce good estimates for the Training Stress Score of your "standard" rides) and use the cumulative data to both track your fitness and plan your training. I'd say that might be more important than using it on the bike (though it is extremely powerful in that setting too).

In my opinion, if you're not prepared to do this, you won't get anything like the most out of it. If you think you'll be able to do all this then I would recommend it for sure.

doyler78

DaveyL wrote:

One thing I would add is that it helps if you are a bit geeky about logging and analysing your rides (using either Golden Cheetah or WKO+ which you can get to work on a Mac I think. I am still not impressed with the latest version of PowerAgent, the software you get with the PT).

To get the most out of the powermeter you need to use it on as many of your rides as possible (at least until you are able to produce good estimates for the Training Stress Score of your "standard" rides) and use the cumulative data to both track your fitness and plan your training. I'd say that might be more important than using it on the bike (though it is extremely powerful in that setting too).

In my opinion, if you're not prepared to do this, you won't get anything like the most out of it. If you think you'll be able to do all this then I would recommend it for sure.

WKO+ is still not natively available on Mac. They are working on the device agent so that direct uploads can be done to their web based subscription service and to that end they have introduced some of the functionality to the web based service (PMC & associated metrics).

One other difference between the models is that the Elite+ computer from powertap has limited functionality so don't bother with it an get yourself another ant+ computer to use it with.

Alex_Simmons/RST

singlespeedexplosif wrote:

Will I rule the world?Ta!

Pithy Power Proverb:

"The Powertap is a tool, not a bolt on motor" - Chris Mayhew

Alex_Simmons/RST

doyler78 wrote:

One other difference between the models is that the Elite+ computer from powertap has limited functionality so don't bother with it an get yourself another ant+ computer to use it with.

The Powertap computer has one really important feature:
The ability to validate the calibration of the power meter.

An inability to do that is, IMO, a deal breaker for any power meter or computer.


When considering power meter options, the most important consideration is the quality of the data produced. Everything else is a feature.

There is no difference in the quality of data produced between the different Powertap models.

genki

Alex_Simmons/RST wrote:

The Powertap computer has one really important feature:
The ability to validate the calibration of the power meter.

An inability to do that is, IMO, a deal breaker for any power meter or computer.

Hmm. Good point because I'm thinking of getting a PT and using it with my Garmin 705. According to my Garmin, there's a calibrate function.
Menu -> Settings -> Ant+Sport -> Accessories, and then Click Calibrate Power at the bottom of the page.
Can anyon confirm if this does what the PT computer does?

doyler78

Alex_Simmons/RST wrote:

doyler78 wrote:

One other difference between the models is that the Elite+ computer from powertap has limited functionality so don't bother with it an get yourself another ant+ computer to use it with.

The Powertap computer has one really important feature:
The ability to validate the calibration of the power meter.

An inability to do that is, IMO, a deal breaker for any power meter or computer.


When considering power meter options, the most important consideration is the quality of the data produced. Everything else is a feature.

There is no difference in the quality of data produced between the different Powertap models.

More useful to use an ant+ usb stick and piece of free software to do that than to use an essentially useless computer otherwise because it is feature limited.

doyler78

genki wrote:

Alex_Simmons/RST wrote:

The Powertap computer has one really important feature:
The ability to validate the calibration of the power meter.

An inability to do that is, IMO, a deal breaker for any power meter or computer.

Hmm. Good point because I'm thinking of getting a PT and using it with my Garmin 705. According to my Garmin, there's a calibrate function.
Menu -> Settings -> Ant+Sport -> Accessories, and then Click Calibrate Power at the bottom of the page.
Can anyon confirm if this does what the PT computer does?

That only confirms that the powertap is zeroed. It doesn't confirm that the zero point is actually correct, within its range of error. By showing the raw torque figure at least a static calibration test (not recommended by Saris) can be carried out to confirm that the powertap is reporting torque correctly.

DaveyL

Why is my little yellow computer "essentially useless"?

doyler78

DaveyL wrote:

Why is my little yellow computer "essentially useless"?

Ok not useless but woefully lacking in features. You can't access setup menus 2, 3 or 4 and you can't view time in zone information (don't really use this feature anyway) or peak power records for 5s, 30s, 1m & 20m (use this feature a lot). I find the pro+ version information poor too so anything which offered me less than this was always gonig to be a problem for me. If you are happy then that's great however I certainly wouldn't be, especially at the price they charge for them.

DaveyL

I didn't realise the head unit is different for different models. I've got an old skool 2.4 SL, so the first wireless one but not ANT+

To be honest I am fine with just seeing instantaneous power during a ride - I can find out time spent in zones, different maximal values etc. after the ride - I don't need to know that during the ride. I have a training plan and can stick to it just by knowing my current power. I wouldn't say no to a Joule or a Garmin 705 if someone was offering me one though!

doyler78

DaveyL wrote:

I didn't realise the head unit is different for different models. I've got an old skool 2.4 SL, so the first wireless one but not ANT+

To be honest I am fine with just seeing instantaneous power during a ride - I can find out time spent in zones, different maximal values etc. after the ride - I don't need to know that during the ride. I have a training plan and can stick to it just by knowing my current power. I wouldn't say no to a Joule or a Garmin 705 if someone was offering me one though!

Ah ok. I don't have either a Garmin or a Joule so I wasn't recommending Garmin as such to anyone I was just saying that the Powertap computer for the elite wasn't worth it so I wouldn't buy the Hub system (hub and computer) but would instead just get the hub and then choose the computer that will do the job for me.

Alex_Simmons/RST

doyler78 wrote:

genki wrote:

Alex_Simmons/RST wrote:

The Powertap computer has one really important feature:
The ability to validate the calibration of the power meter.

An inability to do that is, IMO, a deal breaker for any power meter or computer.

Hmm. Good point because I'm thinking of getting a PT and using it with my Garmin 705. According to my Garmin, there's a calibrate function.
Menu -> Settings -> Ant+Sport -> Accessories, and then Click Calibrate Power at the bottom of the page.
Can anyon confirm if this does what the PT computer does?

That only confirms that the powertap is zeroed. It doesn't confirm that the zero point is actually correct, within its range of error. By showing the raw torque figure at least a static calibration test (not recommended by Saris) can be carried out to confirm that the powertap is reporting torque correctly.

Only the LYC enables you to check the raw torque values at both the loaded and unloaded states (do a static load test in test mode and you'll see what I mean), which is critical for ensuring the meter is operating properly (irrespective of what Saris might say).

A meter out of spec will be replaced by Saris under warranty (well they certainly have in the past).

jibberjim

Alex_Simmons/RST wrote:

An inability to do that is, IMO, a deal breaker for any power meter or computer.

When considering power meter options, the most important consideration is the quality of the data produced. Everything else is a feature.

But given that that is something that can only be done with heavy weights, having your computer with you when you do instead is no problem. The LYC (or the Joule) are the only bicycle computers that do it, but it's trivial enough to do with a laptop and an ANT stick.

DaveyL

Alex,

I was having problems getting a decent number for the stomp test (it was coming out about 13% too low).

I e-mailed Saris and they replied with "We don't recommend the use of the stomp test as a way to test the accuracy of the power tap. There is a much easier way. You can go into the setup screen under the test mode and check the hub calibration. The number you get should be between 500 and 522, if it is significantly different from that you will need to get the hub recalibrated."

Do you think this is as valid a method as the stomp test?

Alex_Simmons/RST

DaveyL wrote:

Alex,

I was having problems getting a decent number for the stomp test (it was coming out about 13% too low).

I e-mailed Saris and they replied with "We don't recommend the use of the stomp test as a way to test the accuracy of the power tap. There is a much easier way. You can go into the setup screen under the test mode and check the hub calibration. The number you get should be between 500 and 522, if it is significantly different from that you will need to get the hub recalibrated."

Do you think this is as valid a method as the stomp test?

No, because all that is telling you is the zero loaded value. It does not tell you a loaded value* and therefore whether the meter is reporting accurately.

If by "stomp test" you mean balancing your body weight on the pedals, then some people are better at it than others, therefore it isn't reliable and would be what Saris doesn't recommend.

What I mean is hanging an accurately known mass from a the pedal spindle on a horizontal crank arm and taking the torque reading.

Only then can you check the slope of the power meter is actually correct.

* Indeed if the zero loaded value is outside of Saris' recommended range, it's usually a good sign something is wrong, however it doesn't necessarily mean the meter will report inaccurately. There are Powertap meters where the zero loaded value is in the 400s, but the loaded tests show the meter is still reporting accurately (just ask Bob Tobin).

Alex_Simmons/RST

jibberjim wrote:

But given that that is something that can only be done with heavy weights, having your computer with you when you do instead is no problem. The LYC (or the Joule) are the only bicycle computers that do it, but it's trivial enough to do with a laptop and an ANT stick.

So you can use an ANT stick and a laptop to get the raw torque reading if you don't have a LYC?

How hard/easy is that to do and how much does it cost?

doyler78

Alex_Simmons/RST wrote:

jibberjim wrote:

But given that that is something that can only be done with heavy weights, having your computer with you when you do instead is no problem. The LYC (or the Joule) are the only bicycle computers that do it, but it's trivial enough to do with a laptop and an ANT stick.

So you can use an ANT stick and a laptop to get the raw torque reading if you don't have a LYC?

How hard/easy is that to do and how much does it cost?

It depends where you live as ant+ cards can be bought as bare boards or you can just get the Garmin ant+ usb stick. Will not cost more than £25. The software is free.

See here:

http://jibbering.com/blog/?p=527

Alex_Simmons/RST

doyler78 wrote:

It depends where you live as ant+ cards can be bought as bare boards or you can just get the Garmin ant+ usb stick. Will not cost more than £25. The software is free.

See here:

http://jibbering.com/blog/?p=527

OK, cool.

A bit more complicated but cheaper than getting a LYC if you are using another CPU already.


In general, it is my experience that PTs are pretty reliably accurate out of the box. But I still think one should check.

DaveyL

Alex_Simmons/RST wrote:

DaveyL wrote:

Alex,

I was having problems getting a decent number for the stomp test (it was coming out about 13% too low).

I e-mailed Saris and they replied with "We don't recommend the use of the stomp test as a way to test the accuracy of the power tap. There is a much easier way. You can go into the setup screen under the test mode and check the hub calibration. The number you get should be between 500 and 522, if it is significantly different from that you will need to get the hub recalibrated."

Do you think this is as valid a method as the stomp test?

No, because all that is telling you is the zero loaded value. It does not tell you a loaded value* and therefore whether the meter is reporting accurately.

If by "stomp test" you mean balancing your body weight on the pedals, then some people are better at it than others, therefore it isn't reliable and would be what Saris doesn't recommend.

What I mean is hanging an accurately known mass from a the pedal spindle on a horizontal crank arm and taking the torque reading.

Only then can you check the slope of the power meter is actually correct.

* Indeed if the zero loaded value is outside of Saris' recommended range, it's usually a good sign something is wrong, however it doesn't necessarily mean the meter will report inaccurately. There are Powertap meters where the zero loaded value is in the 400s, but the loaded tests show the meter is still reporting accurately (just ask Bob Tobin).

Thanks for the info. Interesting, as I was getting worried because mine is slightly out of range (524). I will definitely try the loaded torque test before thinking about sending it off for recalibration or anything.

Alex_Simmons/RST

DaveyL wrote:

Thanks for the info. Interesting, as I was getting worried because mine is slightly out of range (524). I will definitely try the loaded torque test before thinking about sending it off for recalibration or anything.

That doesn't sound too bad.
I thought it was 512 +/- 20 (or was it +/- 12) but my memory might be out on that.

doyler78

Alex_Simmons/RST wrote:

doyler78 wrote:

It depends where you live as ant+ cards can be bought as bare boards or you can just get the Garmin ant+ usb stick. Will not cost more than £25. The software is free.

See here:

http://jibbering.com/blog/?p=527

OK, cool.

A bit more complicated but cheaper than getting a LYC if you are using another CPU already.


In general, it is my experience that PTs are pretty reliably accurate out of the box. But I still think one should check.

Yeah I understand. My thinking on it is that the difference between an elite+ hub system (which includes hub & computer) and elite+ hub is £160. That grossly over values for me what is essentially a pretty basic bike computer. For the configurability and the number of different features I would value it at about £40. I'm not being funny. The hub collects all the information and transmits it. It is the job the computer only to process it so I see it very much in terms of what equivalent hrms offer and that's where I get my value from. When a computer comes as part of package you expect the price to be even lower so if the £160 price is their best price for the lyc then I'm afraid they have their heads up in the clouds. That's the way I see it anyway.

a_n_t

doyler78 wrote:

[
More useful to use an ant+ usb stick

Do these work with any garmin ant+ device? Just cos I've seen them advertised as specific to the forerunner etc.

doyler78

a_n_t wrote:

doyler78 wrote:

[
More useful to use an ant+ usb stick

Do these work with any garmin ant+ device? Just cos I've seen them advertised as specific to the forerunner etc.

Ant+ is a standard so there is no issue in the ant+ usb receiver (ie your garmin device) however you need software to decode it all.

For powertap jibberjim put up this post regarding doing the stomp test:

http://jibbering.com/blog/?p=527

You will need linux though. I have seperate computer running this however it is to run it in a VM

a_n_t

doyler78 wrote:

http://jibbering.com/blog/?p=527

You will need linux though. I have seperate computer running this however it is to run it in a VM

Well that seems like a right load of faff!

Alex_Simmons/RST

a_n_t wrote:

doyler78 wrote:

http://jibbering.com/blog/?p=527

You will need linux though. I have seperate computer running this however it is to run it in a VM

Well that seems like a right load of faff!

LOL - I suppose when you add in the extra computer and operating system to the ANT+ stick, the LYC starts to become a little more appealing

doyler78

a_n_t wrote:

doyler78 wrote:

http://jibbering.com/blog/?p=527

You will need linux though. I have seperate computer running this however it is to run it in a VM

Well that seems like a right load of faff!

It's all relative. It a one off faff ie install a vm running linux. After that it is done. The stomp test itself is a faff everytime. Changing your tyre on your powertap wheel to use on the trainer is faff everytime.

doyler78

Alex_Simmons/RST wrote:

LOL - I suppose when you add in the extra computer and operating system to the ANT+ stick, the LYC starts to become a little more appealing

Not necessary at all

http://www.virtualbox.org/wiki/VirtualBox

I said I used a seperate computer however it could be run in a VM. I have always built my own computers so I have loads of parts sitting about so building up a server was the easy choice for me. For anyone that doesn't have a seperate computer or would rather use their regular computer/laptop then then can just virtualize the thing. One time setup

Captain Fagor

Jesus, this thread is enough to put anyone off buying a powermeter.

Personally, I don't want to be shell out a large amount of money, only to have to be fannying around calibrating equipment, installing software, doubting the data produced, etc etc.