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OJ.... said:Average power means squat in a race situation. Who's fastest is the only thing that matters. The criteria of course is different if you're going for hardest working cyclist of the year award or something.
Tapeworm said:DURING the race, yes, avg power means little. Post-race analysis, however, and avg power, speed, hr, etc are extremely important.
M Sport said:Not really. The analysis is only really meaningful if you can repeat it and compare on measureable comparable efforts. A race from one week to another is not really comparable, there are just too many variable factors.
A much more meaningful comparison is measuring individual efforts on pre-determined training courses and segments where the only variable is the weather.
In a race you’re only trying to win, not set training benchmarks.
Tapeworm said:DURING the race, yes, avg power means little. Post-race analysis, however, and avg power, speed, hr, etc are extremely important.
It is a good idea to validate the accuracy of your power meter from time to time, or when you make a change to something in the drivetrain (like chainrings for instance).simo1733 said:Do power meters have to be tested periodically?Surely they go out of calibration over time.
Alex Simmons/RST said:Calibration is a relatively simple process that all the main units (SRM, Powertap, Quarq) enable you to do if you have the correct head unit. All you need is to be able to apply an accurately known torque to the pedals, typically done by hanging a known mass (which might be zero to 40kg say) from the pedal spindle on a horizontal crank arm and compare the known torque with what the power meter reports.
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Basically that's it, although I'd recommend a heavier mass, 20+kg* and hang from pedal spindle with crank horizontal (eye ball horizontal will do). If you are steady and bike is locked in trainer, and you know your own mass accurately, then you can balance your own weight on the pedal very carefully.microdose said:Alex - can you explian in greater detail how you do the calibration with a Powertap? Is the bike in a stand and then say 10 kg hung of the pedal- giving an instantaneous force down and thus torque which you then check with the theorectical value (based on weight and crank length)?
Michele said:The new german Power2max doesnt allow calibration by what I understood.
Bala Verde said:
Bala Verde said:
sciguy said:
CoachFergie said:I am testing a pOwer2max for the NZ/AUS agent.
The cranks went together and went on smoothly. Paired well with my Garmin Edge 500 and from two indoor sessions and an outdoor session the power appears consistent with my Powertap. I get my Powertap back on Thursday and will do some comparison tests.
Apologies for the sad totals but I spend more time analysing data than
generating it.
CoachFergie said:If a power meter consistently reads low or high then it is still useful data on an individual basis. Have been doing some special trainings with several riders on power meters and one thing is for sure that power alone (even power to weight) does not give you the full picture when comparing riders. So for the price point of NZ$1895.00 (say Coach Ferg sent you for a discount) for the SRAM version (less for TA and more for Rotor) it is a great price for U19s and Masters level riders who don't need the awesomeness of SRM, Powertap or Quarg.
Martin318is said:Why so expensive? The basic unit is 630 euro.....
CoachFergie said:930 Euro for the SRAM which is NZ$1550. Not sure what freight is from Europe but that is the issue in NZ.
CoachFergie said:Did a MAP test today and the P2M read 8 watts lower for max min power than my Powertap. Will use a known weight to manually test the calibration of both and my flatmates wired SRM as he thinks his is reading too high. I should be so lucky.
That's true, although when wanting to compare one's performance over a long time frame, i.e. many seasons (eventually you do tend to change power meters), it's good to know the data is accurate from each meter used. It also factors into other elements of using a power meter, like assessing data collected during aerodynamic field tests when you want to go back and look at previous testing results.Michele said:Im not a coach, but isn't important on a powermeter that the data showed are costant than actual real value?
I mean, your powermeter could show 8 watts lower than the real power you generated, but it doesnt matter as long as it keep showing that x watts at that x effort.
Hope I explained myself as english isnt my first language.