"Low" power readings (badly mounted power2max cranks?)

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by tri

Recently purchased a power2max power meter with rotor 3d+ cranks. After doing a couple of TTs some friends asked me about the figures and told my that my avg watt seemed low. Now I can't say for sure because I've never done any testing in a lab or such to get exact figures but I still wanted to ask just to get some input. May it be that my cranks are badly mounted which makes me get "low" readings?

What I have to show is a intervall session I did on my kurt kinetic road machine. And the numbers are taken from the power2max crank and calculated data using a plugin to ST3 called trainer power (by mechgt) with the resistance curve for my trainer. Supposedly the kurt kinetic road machine should give reliable power numbers.



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by DartanianX

Well, first off tell us a bit more. Weight. Height. Age. It all changes the definition of "low". Look around the Training Peaks blog it has some good information about what the pros put out and there is a chart somewhere that shows w/kg required for certain amounts of time in different levels of the sport, ie pros can do x w/kg for 1,2,5,20,60etc mins vs cat 1 recreational rider etc. Someone will have a link. I cant seem to find it on my phone.

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by thisisatest

kinetic has a cheap computer with a reading that gives you power numbers based on its trainer's speed (it basically knows the force required to turn the resistance unit). you can get it and compare to at least see if youre in the ballpark. or borrow someone's powertap hub

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by Juanmoretime

Can you borrow another powermeter to compare your readings. If you look at this thread:


You will find for mortals big numbers are not necessarily something you can achieve. While I could post bigger numbers if I had a power meter on my ride bike I don't and won't since I don't race it ever. To determine if your numbers are low it takes many factors. Age, height, level of fitness, well rested, training program or are you overtrained?

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by beardking

are your numbers consistent? that is a lot more important than the actual number you get

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by tri

I'm 85kgs (187lbs), 193cm (6.3 feet and inches), 27 years old.

Haven't had the p2m cranks for that long but I have some data from an actual TT-race which was run on a fairly flat circuit of two laps.

Distance: 33,59 km
Climb: +113,9 / -122,4
Time: 45:51
Avg speed: 44,0 km/h
Avg power: 324,4
Weather conditions: Min./Max.: 16,4 °C/17,0 °C; Pressure: 1015,1 mbar; Humidity: 91,2%; Dew point: 15,2 °C; Wind Speed: 6,7 km/h; Precipitation: 0,0mm

What I'm aiming for is to find out if I can't trust the numbers (don't know how daft it seems or is not trusting a power2max power meter). I'm afraid I can't borrow another power meter this is what I have. The numbers generated for the kurt kinetic is with the resistance curve from kurt kinetic them selves. And is claimed to be accurate and "matched" with a powertap.

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by beardking

i also have a kurt kinetic trainer. i don't think their power curve is very accurate, or it never was for me and i don't worry about it now i have a power meter anyway.
are you doing the spin down test to calibrate the turbo before you use it and do you set the tyre pressure the same every time

anyway - 324 watts is a good power output, if thats noticeably low then :thumbup:
and 44km/h seems like good going as well but your speed would depend on conditions and how aero you are.
here is a thread I've been looking at recently with some testers power outputs on http://www.timetriallingforum.co.uk/ind ... opic=70736

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by tri

The link you posted, I don't understand "What average power did you need to break 20 minutes?" break what?

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by Dalai

Popular TT distance in the UK is 10 miles. Reference is power to beat 20 minutes for this distance...

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by beardking

indeed. its a 10 mile tt so 20 minutes is 30mph.
but there are a lot of power figures posted for other times too.

your 44km/h is 27.34mph so would be a time of 21:58 in a 10. just trying to give some idea of other riders outputs

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by mrfish

+1 regarding the trainer data. I know from experience that the wheels, tyres, setup and so on can make a big diffrence to how the trainer rides.

At the end of the day it does not matter what power number you hit, as power numbers don't win races. Instead you just need to be reasonably sure that the power meter produces a consistent measuremtn, and that the numers move upwards. So you might try riding the same circuit every month and noting the wind and time. If the power numbers go up and the time comes down then you are doing something right.

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