My first race file.

[GWPOS]

Was just wandering after using my unit for the first time in a race(xc mtb) if this file looks good. Things seemed to be ok but since I have never used a power meter I wanted to be sure if I have this unit setup properly. All I want to do is make sure that the power numbers are somewhere near to what they should be. Thanks

iBike_09_20_2009_1017_15_Miles.csv

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[Velocomp]

This looks fine...big push at the end!

[Morocco Mole]

That does look pretty good, quite high speed in some places, you must have had some pretty open fire road descents? You might need to re-test and increase your FTP, IF is 1.054 and it's unlikely you managed to exceed your FTP for over an hour (by definition you can't ). Either that or it could be an indication that your MTB Profile for the iBike is giving higher power numbers than it should be. How did you calculate FTP, same MTB bike\dirt profile, or on a road bike?

[GWPOS]

I used my old xc bike on the road with the suspension locked out. I created another profile for this bike with changes that coachboyd had told me to do(CRR .0070 for the road bike and .0100 for my xc race bike). I know using this on a mtb is not what this power meter was designed for but it averages out pretty well. I did my first FTP test on that bike, but that was before coachboyd had me change some numbers around on the profiles.

This is why I wanted someone to look at this file, it seemed like maybe the numbers were a little high. I also blew my legs up on the second lap by going to hard for to long on the fireroads,,,,and yes that is almost all there was was fireroads on this course so that is where the high speeds came from. Went in well rested and set to peak for this race but blew it by going out to hard, which is why I purchased this power meter to learn how to pace and also to improve my overall training.

So if the number look to high I will need to know somehow so that I can tweak the profile a little bit with someones help. Thanks for any input.

[arkiejon]

You do understand that it all depends on whose standards you are trying to live by?

If you are just trying to improve for yourself and are not looking for bragging rights that your Power Meter is better then someone else’s or compare to someone else. Then it doesn’t matter. Lock in some settings and stop mucking with the thing.

I have two bikes, Both are road bikes, One hangs on the wall covered up and I ride the devil out of the other one. Unless I want to compare the two bikes to see if I do better on one or the other, There is just no need to know if the numbers are accurate compared a standard.

I say ride your fitness test and work out and test again. If you keep jacking around with the numbers between test, would be like comparing apples to oranges.

But then again I ride for fun not money, so in my case It don't matter.

[Morocco Mole]

I agree with arkiejon to a point, at some stage you need to be happy with your setup and just get out and ride. But, as it sounds like you are tracking TSS, ATL and CTL with WKO+ then it is important to establish an accurate FTP with that profile. If you train with multiple bikes then you will want this to be as consistent as possible across all the bikes. If, as we suspect, your MTB profile is approx 20 - 30 watts too high, then either your CDA or CRR or both is too high. To get a feel for how changing these values effect power, have a play with the Tweak CdA,Crr, & Cm tool in iBike. Also reducing weight will have a negative affect on power.

For example I reduced your CDA to .4 and CRR to .0075 which changed you NP to 255 and IF to .974, quite possible for a 1 hour duration MTB race. Of course, the alternative is that your other profile was reading power a bit low, maybe you need to look at tweaking both until you get things looking closer. I'm about to take my second wireless mount off the TT bike and put it on the XC Race machine and start creating a new profile. I know my road profiles are very accurate as they have calibrated to a powertap so it will be interesting to see what sort of number I get on the MTB. I will share as soon as I have my data. Cheers Jim

[GWPOS]

Thanks again for the input everyone. And yes I am tracking my TSS etc. for training purposes which is why I want both bikes to be as close as possible to each other in wattage readouts. If I do intervals on the road and then do intervals on the dirt I need an FTP that is constant between the 2.

Now here is where my problem lies since I have never owned one of these or any power meter for that fact, I don't fully understand yet how to tweak the numbers to get closer to the right number in watts because I am not sure what the right number is. That is why I greatly appreciate any suggestions or help I can get. Thanks again and let me know how your mtb setup goes.

Also I used an original FTP test which I got before coachboyd helped me by changing some of the numbers. So I would guess that I should need to do another FTP test and then see how it goes.

[Morocco Mole]

yep do the FTP again, but also play with the tweak settings, it's not destructive and good for learning how CDA and CRR affects power.