#sstat4 .8w/kg

Personally i like my pm to be accurate and precise. I paid money for it, therefore i would rather have something that is better than the rest. I don't "need" my pm. My body is really in tune with my RPE and i can tell if my powermeter needs to be zeroed out or re-calibrate just by riding it and looking at the wattage and how my legs feel. I rode a ride where i got 3 mintues of power data total due to drop outs, and ever time the number came back on my screen it was the exact number plus/minus 5 watts i wanted to see. Even with my in-tuneness i would rather have an accurate and precise measure, especially so in 3 months i can look back and see real changes, not just slope related gains and losses.

let me get this straight: you're a frequent poster in a thread about training with power and you're expecting us to believe you feel that power is not important...because you don't race with power on your screen?

personally, i think you are just being argumentative for the sake of it, i.e., in character...like when you insist you don't do intervals but do hill repeats or whatever in strava and just don't call them intervals. if you don't understand why good data is important, i can't help you.

for others in this thread who want to measure progress (via power) over time.... y'know, like the purpose of this thread... accurate data IS important. being able to field test (and update) the slope of one's device gives the best chance of that.

we don't know why zig's old unit was bad and we don't even know if his new unit is good (i'm assuming he gets ZO right each ride), but your suggestion that someone can 'just change your threshold' trivializes the problem. if his slope was wrong in the old unit or the new one, or both, his readings will be too high at times and too low at others. without testing slope, we don't know when it will read high and when it will read low. pretty material stuff for training, which ultimately impacts racing.

this becomes material when someone gets a new unit for any reason, warranty or otherwise, and has years of data. sure is nice to know that changes in power are real vs an inaccurate device.

it's ok that you're not an expert on this, and admittedly it is not universally understood. people don't often understand the problem for a few years down the road, after they're on their 4th device (warranty or otherwise) and have years of data they are trying to use for comparison

you're giving advice that is wrong. this one is not "YMMV" or us "agreeing to disagree" -- it's simply incorrect.

oh yeah, if you have accuracy that's great. you can use it to predict climb times via strava if it's generally accurate and comparable with others.

I use 3 different power meters, so I care that they are all generally close enough to each other to be consistent for tss and the like.

You're not listening, or not understanding, but that's in your character.

Sorry Zigs, you're life is ruined, I guess.

Really I have bad news for us all: http://www.slate.com/blogs/trending/...icrograms.html

you are a heck a lot less witty than you think you are.

aren't we all?

says the guy who prides himself on not listening? pretty rich, fudgy.

i read what you wrote. you told zig how to fix the problem. you were wrong. you probably just don't know what you don't know, but that doesn't stop you from posting (ever). it would be excusable if you copped to it.

this one's not opinion and "meh works for me" doesn't hold.

no one said zig's life is ruined, but it might help him and others to learn to pay attention to something they might not have otherwise known about that gives them better data for years to come. it is not as simple as adjusting one number.

yes, i will call you out when you make a statement that is based on something wrong. if that bothers you, stay quiet when you don't understand something.

I confess, I only replied to you guys to see how many words I could get TR to type. If you're super easy to wind up and insult my character over trivial things, you earn your ****ed-with-ness.

Zigs already has a new meter that's probably accurate and he's likely 1/100th as stressed at Eric.

Anyhow, I guess you all are right. Accuracy is key. :thumb:

Hey now. If you find out your PM has been reading inaccurately, adjusting your zones to compensate is not "wrong."

Doing a slope calibration on the new meter is well and good, but the truth is that people derive different utility value from measurement accuracy, and assign different cost value to the work of achieving that accuracy.

You, tetonrider, clearly derive very high utility value from measurement accuracy, and assign relatively low cost value to taking the trouble to calibrate and verify measurements. (I remember a long post about floor pump accuracy a while ago.)

Other people can have different priorities. Personally, if I found out my old PM was inaccurate, I would adjust my zones and call it good. I'm just not going to take the time to retroactively adjust old measurements. I would not disparage the advice to do so, and I would certainly listen to it with an open mind, but at this moment I wouldn't bother. This is not what you would do, but it's not fair to call it ignorance or lack of understanding.


[edit] reading the back and forth, it sounds like the conflict is more about some preexisting personality clash than anything else. I don't have a dog in that fight.

you make lots of assumptions about who is stressed.

posting with the express purpose of riling people up did really well for the community at socialcyclists, right? if you're admitting to still doing it and bringing it here, i can only assume your intent is to degrade this community, too.

i prefer to stick to factual posts, as i did above. sorry you resort to poking and prodding, but i guess that is what people do when they have nothing constructive to add yet still need attention.

personally, i think you're just a coward who is now hiding behind another of your classic excuses -- "i'm not wrong, i was just saying something wrong on purpose."

technically, yeah. Don't think anyone of us here have the wit of Oscar Wilde or Gore Vidal. But at the same time, not many here are so loath to admit a mistake that they offer only retorts only they themselves believe to be witty.

yes.
yes.
and one side yes, on my side I just caved to my constant temptation to poke the hornets nest. it's too easy, it's not nice and I am sorry.

What mistake?

(sorry, doing it again. I know about slope, but when he said it was 10-15w low I assumed he meant at FTP. the zones below are fungible enough that if it's a little high in the low zones and a little low in the high zones, the affect to training is likely minimal)

globe, i hear you on individuals' utility & cost assessments and have many times stated in the past that people figure those things out for themselves.

two things in your post referring me are not right, though:
1) i have not called differences in value placed on accuracy ignorant or uninformed. i have specifically called it incorrect to tell someone that data inaccuracies can simply be fixed by assigning a new FTP. there is a subtle but important difference. i'll get to that in a minute.

2) you wrote 'this is not what you (meaning me, fixing data) would do', but that is incorrect. although i didn't bring this up in the earlier posts, i wouldn't/don't do this mainly because you really can't correct large batches of data that way. (you can fix a day's workout if you know the slope or ZO was off, though.) i am interested in what is happening with a meter NOW so that it reports correctly going forward.

in case i haven't it stated it clearly before i am sorry: the point of my messages is to create awareness that there is more to power meters than zero offset, and although they are expensive devices we unfortunately cannot rely on the factory to deliver them set up correctly. no matter what meter someone chooses, it is not a trivial purchase, and it can be nice to know that the ability to check -- and update -- slope is a feature that some have and others lack, even if one chooses not to buy one with that capability.

a few simple steps -- if one chooses to do them -- can improve the data. the problem is that many people are not aware that those steps can be taken.

i've got no problem with someone making their own choices about the utility of accurate data, but many people are making a DEFAULT choice by assuming what they've got (from the factory) is good. from what you have written it sounds like you are aware of data implications and choose to handle them however you wish. that's great. if your meter's slope has changed without you knowing, it's a simple adjustment to zones doesn't really fix the problem, but that's ok for you.

others reading this might be surprised to learn there is a 5-minute process that can be done 1 or 2 times a year that can increase reliability of their data. not exactly burdensome. yes, you are right -- i do place a pretty low cost to making that 5' check every 3 or 6 months.

some (not all) people will discover problems down the road. this becomes particularly sensitive when a person reaches the point where gains are smaller relative to the work they must put in AND when they have had a meter that was over-stating power. it is a hard pill to swallow when gains are masked by a new (correct) meter.

many people, but not all, derive utility from comparing today's results with those of months and years ago. if data's not accurate from the past, this data is lost.

some people base hundreds and thousands of hours of training off of the numbers their meters report. one need only scan a few pages of this thread or the training status thread to see how one workout's number can make them feel like a rock-star or a washed-up rider.

to me, a few minutes is worth the upside, but again as long as people know there is a way to improve data (with some meters -- this affects a buying decision) and that it needn't take all that long, then everything else is good.

I should also confess that I do use power in my races. I keep it on my screen for those moments when I might feel like my legs are jello, but a good or decent number at that time gives me confidence to dig harder.

to bring this back to civil discussion, i agree with the notion that zones are fluid.

i'm not prepared to say what is material for someone else, but there are some at the sharp end of their fitness who train all year to gain just a handful of watts (5? 10?) at threshold over the prior year. being on the cusp of a zone can be material to a person, so depending on what exactly is happening it may or may not have a minimal training effect (esp psychologically).

unless zig has the old meter and/or knew exactly what was wrong, we just don't know when the meter was reading high or low. i'm assuming ZO was checked regularly. his old meter might have been a random number generator...some electronics problem causing random fluctuations in ZO during a ride (i've seen it), but let's put that possibility aside.

it could be that the meter was 10w off at threshold but reading low at vo2 & above or high at tempo & below, or it could be reading high for harder efforts and low for easier ones. we just don't know. one error is worse than the other -- but we really cannot say how to correct it without knowing more. we'll never know that info.

to make this more generic than zig's case because we are just guessing at some details, let's say a well-trained athlete works his @ss off trying to get from 390 to 400w. he learns his meter is screwed up, so he gets a new one from the factory. all his data from the past year suggests that 390 is his threshold, and he's been plateaued, maybe getting frustrated. unbeknownst to him his meter's slope was off in a way that was over-reporting threshold.

he gets a new meter. the factory nails it and it stays rock-solid forever. at threshold he's putting out 370w, but it is 370 real watts.

that athlete has suddenly lost the ability to compare his old interval sessions and race data to his new stuff, to see if he is improving year over year. moreover, he's probably going to be frustrated (hard not to get attached to higher numbers, even if they're not real). maybe he goes out for his first few TTs and even blows up because he is still trying to hit that 390 when he should be aiming for 370.

if he'd taken a few minutes to check the slope of his first meter, perhaps quarterly, he'd have corrected the problem and would have better data (or less bad data) that would be relevant for the future, and he would have not gotten in the mindset of thinking he could do something that he clearly could not. he also might have detected the presence of a meter in need of replacement sooner.

when he got the new meter, that would be checked, too. new #s would compare to old #s , and it would be easier to identify real progress vs changes in the meter.

as said above, i can't decide for a person if the point at which it matters is a couple watts or 30 watts, but at some point the differences do matter.

although hypothetical numbers, this is a real scenario.

i'll wager everyone just assumed you were lying in order to create an argument (e.g., same for your statements about intervals), but when you do stuff like that you realize you become less credible overall.

i'll speak up when something inaccurate is posted, and this was factually inaccurate.

the personality clash is about fudgy having a long history of arguing for arguing's sake, and just trying to stir $hit up/get attention when he's not getting what he needs.

he admits as much in this thread...he just can't help himself.

i'd prefer to stick to the facts, and i'm happy to talk about pros and cons of various systems, with each person walking away to decide what is right for them. i might learn something new or help someone else out.

personally, i only wish i could have read years ago a back-and-forth discussion on steps i could take to get better data. it would have affected decisions i made.

http://i.imgur.com/yluLFBk.gif

I quit clicking "view post" a while back, when it was clear an unhinging was occurring. Go to bed, it's gotta be late in wherever.
http://i.imgur.com/x4fKPTQ.png

100% truth.

I could write up plenty of stories about people obsessing over numbers, or going into near meltdown from chasing numbers when their meters go bad. Or thinking they were making progress when they weren't. It's bad enough this time of year when indoor training skews numbers.

So having accurate settings matters. Because sooner or later you're going to get a new power meter. Or have yours serviced. Or change your chain rings. Or buy a second meter. Or wonder why you're not winning with your 1600w sprint.

And those settings move over time, especially when a unit is new. So being able to calibrate to a known force or weight means you're going to be consistent in your data collection and how you approach setting up training or riding a TT or a pursuit.

I see nothing wrong with arguing for the sake of arguing. I personally love it. So do others. And some people don't. Whatever.

well, i've sure gotta hand it to you with that one. that was so creative! i've never watched you get called out then ultimately slink away -- but not before closing with some implication about "the other guy".

it must be so rewarding for you to know everything about what others are feeling from behind your computer. how do you do it with such accuracy?

was it life-affirming for you to make up some stuff and post it here tonight with no intention of adding to the knowledge base? did you cross-post to your other forums, too? good. glad you feel better for it.

me? i'd prefer to stick to quality discussion, but you seem to enjoy the hurl-and-hide bit when you're wrong. i could almost respect you if you either knew what you were talking about or had the courage to not run and hide.

sure. i think everything has a time and a place, even devil's advocate stuff. usually a devil's advocate still has a point worth discussing.

posting wrong info or deliberately lying when one has nothing of substance to add in a thread that is supposed to help people specifically looking to learn comes across, to me, as attention-seeking. it's not even arguing for arguing's sake -- it's being a d-bag.

i may well be in the minority, but forums that have good info are much more interesting to me than those with a high ****-to-credible-content ratio. the mods here do a good job on that. i've seen other forums destroyed without it, or the knowledgeable members driven away.

but whatever.

This actually just happened to me. I got a second power meter late in the summer, and really have just started riding it with any consistency. It's for a bike I keep at my house up north, so it doesn't and won't see a lot of use. An FTP test on that bike revealed that there was a discrepancy between that bike and my main bike. Further exploration revealed that the slope on my race bike was off by a good clip. I have made the assumption that when I send my stuff in (yearly) it's calibrated properly and such. I have no idea, and no way of knowing when this drift occurred. I wasn't even aware that drift could happen, might happen, or frankly how slope is set or even what it is. I am aware that I've struggled or couldn't hit certain numbers in particular workouts and that my FTP tests seem low for the way I ride and the results I get. It's also possible that's due to a combination of age and injuries. I had a few hand wringing moments, but the truth is it doesn't matter much. I won the races I won. The meter was accurate within itself for at least a period of time where I could base my training off my tests. I lost some mental ewang contest which likely had me push harder probably helping me improve.

The two meters are now calibrated so they are accurate to one another. My philosophical training is in Cartesian epistemology; do I know with certainty they are 100% accurate to some power number standard that exists somewhere? Not even no, but hell no. But I'm told that they're good enough for government work.

Would it be nice to not have run into this? Yes. Quite. I'd like to look back 2 years at a series of one minute intervals and be able to compare them to the ones I do next week. So it goes. That guy and his body don't exist any longer anyway.

Could it be corrected in hindsight? I'm told it depends. If I have a bunch of data that I typically don't pay much attention (precise body weight day by day, wind speed, the numbers of angels dancing on the head of the stem bolt that day).

Would that be simple? No.

I took the Ornery one's point to be sort of where I ended up in this. Fix what you can and don't worry too much about it. It it what is, move on.
I took TT's point to be do your homework so you prevent it from happening.

They're not really incompatible positions.

I've looked back at my workouts over the last jag of time and know that they are most likely X% low. I have a pretty accurate sense of what that X is. And whether my power in a race is X or X+Y it ultimately doesn't matter. It's done, or it's in the future, and the handwringing ain't changing much about it. Fix what you can fix and move on.

But, hey, I'm a guy who's CTL is totally fubar in WKO- (I use the minus version), because the obvious and intuitive way to change FTP globally changes it. Heavens knows how many times I've messed it up, but my CTL is quantumly different than what the coach shows. I live with it, mainly because no one can tell me how to fix it.

Sorry if I missed it but can someone point me to a link/thread that discusses how to recalibrate a powermeter? I have a Powertap if that is relevant.