Power2max power meters..

[durianrider]

Anyone had one? They are the best priced crank based power meter with the most rational method of calibration and you don't have to send em back to Germany for the battery to be replace.

Anyone?

 

[PACONi]

Anyone had one? They are the best priced crank based power meter with the most rational method of calibration and you don't have to send em back to Germany for the battery to be replace.

Anyone?

I think you should do your homework on this PM. I was looking at one as well. What I've read is that they have issues with temperature fluctuations, especially at the beginning of a ride. Also the 'on the fly' zeroing seems a bit hit and miss to me.

Have a look at the review in the features section StageONE meter that will be coming out early next year. I'm going to keep an eye on it, check some reviews/tests against existing meters and then maybe get it.

Or win the lotto and go SRM.

 

[durianrider]

Thanks for that.

I can afford an SRM but the thought of sending cranks back to Germany from Aus just to change the battery is absurd IMHO.

My powertap has been great and just looking for something for the gf.

I think the temp issues are more if you train in really cold climates. Thats not me at all lol!


If the stage one is a good product it will TKO the power meter market for sure.

 

[Alex Simmons/RST]

I can afford an SRM but the thought of sending cranks back to Germany from Aus just to change the battery is absurd IMHO.

It's possible to do it yourself if you know what you are doing, although I would recommend using SRM's service centre in Christchurch. It's a once every 2-3 season job.

 

[STODRR]

Thanks for that.

I can afford an SRM but the thought of sending cranks back to Germany from Aus just to change the battery is absurd IMHO.

My powertap has been great and just looking for something for the gf.

I think the temp issues are more if you train in really cold climates. Thats not me at all lol!


If the stage one is a good product it will TKO the power meter market for sure.

If you buy a new P2M it should have the new software on it that is supposed to have fixed the temp fluxuations problem some people were having. If you buy a used one you will have to send it in to get the softwar update.

 

[durianrider]

It's possible to do it yourself if you know what you are doing, although I would recommend using SRM's service centre in Christchurch. It's a once every 2-3 season job.

Really?

What about calibration ease?

Ive had a power tap and still rate it. Easy to self calibrate. Its going on my GF's Trek and I need a new power meter. The Stages Cycling looks like the ticket so far.

 

[Alex Simmons/RST]

Really?

What about calibration ease?

Ive had a power tap and still rate it. Easy to self calibrate. Its going on my GF's Trek and I need a new power meter. The Stages Cycling looks like the ticket so far.

You can't calibrate a Powertap. You can only check its calibration.

As for calibration ease, SRM still has the edge on all the others in that department.

 

[durianrider]

Can't calibrate a PT?

http://www.cyclepowermeters.com/powertap-garmin-calibration-check-76-c.asp

 

[Alex Simmons/RST]

Can't calibrate a PT?

http://www.cyclepowermeters.com/powertap-garmin-calibration-check-76-c.asp

Correct, you can only check the calibration, you can't set/correct/adjust it.

If your Powertap's calibration is out, tough, you're stuck with it.

Setting the correct calibration on an SRM is a trivial operation and for a Quarq it's slightly more complex due to the need for some extra hardware to communicate with the Quarq.

Also keep in mind that the precision of Powertap calibration checks are somewhat less than those for an SRM, which provides torque data at 5-10 times the sensitivity of the Powertap (how much more sensitive depends on the gear used for PT check).

 

[Alex Simmons/RST]

If the stage one is a good product it will TKO the power meter market for sure.

I'm not so sure. I think it'll have potential to be another gateway drug, but not a killer app.

It only measures the left leg and doubles that to report total power output, which relies on the invalid assumption that power production is left-right symmetrical, when in fact L-R asymmetry is normal, and not only is asymmetry normal, the level of asymmetry is not consistent person to person, nor is it consistent for the same person (it varies depending on absolute and relative power output, cadence, fatigue level, type of riding, bike and so on).

 

[durianrider]

I'm not so sure. I think it'll have potential to be another gateway drug, but not a killer app.

It only measures the left leg and doubles that to report total power output, which relies on the invalid assumption that power production is left-right symmetrical, when in fact L-R asymmetry is normal, and not only is asymmetry normal, the level of asymmetry is not consistent person to person, nor is it consistent for the same person (it varies depending on absolute and relative power output, cadence, fatigue level, type of riding, bike and so on).

Some good points AS.

I'm still not sure you say you can't calibrate the PT when Garmin say you can in that link I provided before.

 

[durianrider]

Despite measuring on one side (left), the unit does correctly give you total power by taking the left power and applying an algorithm to determine total power. If you compare it to spider based power meters, that is measured at the spider, which takes into account force from both cranks.

Note however that none of the left/right crank based power meters currently available on the market today however independently measure left/right power. They all estimate it. The only direct force power meter today on the market that separately measures left/right power is the Polar/Look pedal based power meter. There are crank based units coming down the line next year that will measure it independently (i.e. the ROTOR system).

 

[Alex Simmons/RST]

Some good points AS.

I'm still not sure you say you can't calibrate the PT when Garmin say you can in that link I provided before.

Just because Garmin misuse the word calibration, does not make it so.

Calibration of any measuring instrument is a process of ensuring that the device is reading accurately. That involves both checking it and making the necessary adjustments to ensure the data is accurate.

You can do the first bit with a Powertap, but not the second.


It's like a set of bathroom scales. It gives you the ability to check the zero point is set correctly by reading zero kg when you are not standing on the scales. But what if you then place a precisely known 50kg mass on the scales and they read 48kg? There's nothing you can do to fix the bathroom scales that will make them accurately report weight.

 

[Alex Simmons/RST]

Despite measuring on one side (left), the unit does correctly give you total power by taking the left power and applying an algorithm to determine total power.

All its "algorithm" does is double the left leg reading, which falsely assumes that our power output is always symmetrical, and under all circumstances.

This is not the case. Asymmetry is normal and it varies significantly.

Note however that none of the left/right crank based power meters currently available on the market today however independently measure left/right power. They all estimate it. The only direct force power meter today on the market that separately measures left/right power is the Polar/Look pedal based power meter. There are crank based units coming down the line next year that will measure it independently (i.e. the ROTOR system).

Sure, but that's a red herring and does not speak to the invalid assumption being made by StageOne.

And besides, even the StageOne can't tell you left leg data independently, since the cranks are connected it's telling you the net forces on the left crank applied by the whole system (i.e. both legs).


As for knowing left-right power, to be frank, it's way over rated as an issue to be concerned with in any case, but that's an entirely different discussion.