I had an anomalously high power reading on Saturday's time trial. How do I tell whether my torque was out of wack?
Did you coast before or afterwards? One would see a non zero torque reading during those times if there was the specific issue you think you had. I assume you meant overall just too high and not just a one time spike.shawndoggy said:I had an anomalously high power reading on Saturday's time trial. How do I tell whether my torque was out of wack?
Woofer said:Did you coast before or afterwards? One would see a non zero torque reading during those times if there was the specific issue you think you had. I assume you meant overall just too high and not just a one time spike.
non-zero torque and watts while COASTING (i.e. not pedalling) is the key point. Very easy to detect on a PT....shawndoggy said:like I'd be seeing a torque reading at zero watts or zero torque with a watts reading? There do seem to be a couple of instances where torque is "--" but there is a watts reading (like 8 or 22 watts... barely anything).
peterpen said:To my uneducated eye, it looks easiest to spot in interval #5 - there are periods with 0 rpm cadence but watts and torque readings. You can also see this at each of the turns.
Not sure when your TT was, but for mine at 10:30am, it looked like it was a rare case of going hardest from the gun producing the best times. We had a strong headwind on the first section which turned into a cross-head after the first turn. Tailwind was very welcome after turn #2.
yes if the offset was constant or reasonably so. i don't have access to wko here but if you dumped a .csv I could take a look for me. I've corrected a couple of my own files over the years.shawndoggy said:Argh. As suspected. Is there a way to glean "corrected" data?
Ours was exactly opposite... wind out of the NW, so tailwind out, xwind on second leg, headwind on third, and dead on into the wind on the last leg.
rmur17 said:if you dumped a .csv I could take a look for me. I've corrected a couple of my own files over the years.
http://www.midweekclub.ca/powerFAQ.htm#Q46shawndoggy said:Cool! I'll resave as csv and post-up when I get home tonight.
rmur17 said:http://www.midweekclub.ca/powerFAQ.htm#Q46
here's a link if you want to do it yourself. Not that much to it really. then re-import the new .csv and get rid of the old 'inflated' file.
I wrote these out (more detailed instructions) on the wattage list (formerly on Topica, now on google) in 2004:shawndoggy said:Wow, I read that and I understand the concept, but I have no idea how to make that happen in excel. The csv file is attached. It looks like it is reading "high" by 1.6 nm. If someone could fix, I'd be eternally grateful!
jbvcoaching said:4) Create a column that is a formula, you want to subtract the lowest[/size][/font][/color]
observed torque value from the torque column. Column should be as long as
the file itself.
here you go Tom You should be able to import this file straight in - I named it workout 'b' for the day. If you're happy with it - just delete the original workout.shawndoggy said:THIS is the part I don't know how to do... I'm an excel doofus.
ah smarter folks than I have figured this out. No doubt watts aren't linearly affected by the offset but torque has been shown to.woodgab said:I was told by PowerTap folks that there is no correcting a non-zeroed file. Believe me, I want to save my data if I could. When asked if the mistake was linear to the power readings I was simply told it is not. So, you can not take the 0 cadence torque/watts and deduct that constant from all readings via Excel. In my case, watts at 0 CAD ranged with speed, from ~15-40.
Having said this, I bet doing it is better than not and believe its the only way to save the data for ATL/CTL/TSS... use.
If the unit is reading high, if you plot torque versus time, you should see a minimum reported torque, which was reported during coasting periods. Obviously, on a trainer, there is likely no coasting until the end of the workout, when you may see it.rmur17 said:ah smarter folks than I have figured this out. No doubt watts aren't linearly affected by the offset but torque has been shown to.
Now that assumes a 'well-behaved' or quasi-constant offset. If it's simply bouncing around all over the place (hub problem other than simple failure to zero), then I agree the case would be hopeless.
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