zymphad

Fun video for power meter. He actually does it, it's not a vlog. Maybe not a expert, but he did train with a power meter while on the Cervelo test team.

RChung

Really? I think I tend to qualify my posts pretty well. I stick to objective quantifiable assessments, point out what you can and can't do with each power meter, and don't assume what other riders will find important. I include everything and leave that decision to them. It's you and Chaadster who appear to think you know what others will do or need to do in the future. My initial claim was that the data produced by a Power Tap is higher than the data produced by a Stages (I also said Garmin Vector S, but that was premature -- I haven't actually analyzed the data from a Garmin Vector S yet). That's objectively quantifiable.

I don't know -- I couldn't do a set of 10 sec kilowatt sprints if you paid me. However, I have a friend who is a track sprinter who was looking to upgrade from his wired SRM to something wireless and a buddy loaned him a Stages. He says that after one workout he went back to his SRM. I didn't see his data file, though, so I couldn't tell you what the variance was.

Well, first, I didn't say that a wristwatch and speedometer and HRM were “better” than a power meter – you just made that up. Don't do that. I said that if all you use a power meter for is training, then you can do almost as well with just those things and they're much much cheaper. Nor did I say that the Stages negatively affects the training efficacy of the majority of cyclists -- you just made that up. Don't do that. I did say that there are specific uses for which the Stages doesn't produce high data quality, and I gave examples of those uses.

Training is one of the least demanding uses for a power meter. Cyclists have been training with good results without power meters for around 150 years; runners and swimmers still train pretty well without power meters, using only wristwatches and distance. You don't need a power meter to do interval training if you use the same road and have a wristwatch. If you're using a power meter just to track training load then you're replicating something that could be done with a wristwatch or a HRM. It's certainly easier with a power meter but you could do it without one. A few months ago I pulled together this plot from 10 rides I did up a local 2 mile long 5% hill. I wasn't cherry-picking the rides – they happened to be the 10 most recent rides at the time I did the plot. Because I'm so slow I've omitted the scaling on the axes out of personal embarrassment (yeah, I'm exactly the kind of elite racer you think I am), however there's about a 20% spread in speed and power. As you can see, the R^2 is 0.97, and that includes one climb on a really windy day. So this shows that speed or a wristwatch on a regular hill can fill in pretty well for power. Not perfectly, of course, but certainly good enough for training purposes.



The real advantage of a power meter is in doing things you can't easily do with a wristwatch and speedometer and HRM. This is particularly true after you've been training for a while and have harvested most of the low-hanging fruit, but sometimes sooner than that. You can't easily look at pedal force/pedal speed without a power meter. You can't easily do aero and rolling drag estimation without a power meter. You can't do the new FRC which will appear in the next version of WKO+ without a power meter. However, not everyone is interested in doing those things, and I believe I make that clear every time I mention these things. I don't presume to know what others will need or don't need, unlike you. If someone thinks they're going to want to do those things someday, they may want to know in advance what a particular tool is good for, and what it's not.

I'm obviously a big fan of power meters. I've been using them for a long time – but I also understand that not everyone is like me, so I point out that others can train effectively without one. I've also developed some methods that you can do without power. I'm not sure why you think that I'm talking to only one audience, and that that audience is elite riders. The evidence is that I am talking to a broad spectrum of riders, of all abilities.

If guys are spending cash to buy a power meter just to do the things that they could do with something cheaper, why? As one of my friends says, it's so they can talk watts with the cool kids. That's pretty much penis envy. Ray (not the guy who said that) and I were talking about the Stages a couple of months ago. We both agreed that everything has a use case. The thing is, we don't presume to know what everyone else's use case is, so all we can do is lay out the full story and let people decide for themselves. So that's what I've been doing. I just lay out the facts. Data quality with a Power Tap is higher than data quality with a Stages. Training (unless you're doing very specific kinds of training) doesn't require very high data quality. There are some things that require high data quality, but not everyone is interested in doing them. If all you're doing is (genreral) training, you can get a large fraction of the training effectiveness with just something like a Garmin 500, or even something cheaper like a wristwatch or HRM.

chaadster

Oh, good, as I am too, and I don't mean to come of as combative or push the discussion into a debate over irrelevant hypotheticals. I was trying to ask questions that would help clarify things so that you could make a properly informed decision.

Also, to be clear I do not have, nor have I used, a Stages meter, and I have no affiliation with them. I actually use a Powertap wheelset (purchased before Stages was available) and a Cycleops Powertap stationary bike for my power training, so I'm not trying defend Stages because I bought in, nor am I trying to dissuade you from a PT. As the market has shown, there are compelling reasons for someone to buy either.

halfspeed

I'm constantly amazed that you keep coming back here providing useful information for free when you get so much static for doing so. Pearls before swine, indeed.

canam73

You over qualify to the point that your s/n ratio is stifling. And no, your assessments are not always quantified. Case in point, your dismissing the Stages for short intervals is based apparently based on an anecdote from another rider. And although this is my assumption, I am guessing he is higher up the competition ladder than cat 3 me.

Should every assessment be based on my needs? No. But my use is likely more typical to this forum than your track sprinter friends. And fwiw, more than 1 or 2 1000w sprints in a set is tall order for me, too. I picked the number because it's round and would provide an easy example to scale one way or another.


I don't expect you to care or remember my info, but for the record I own an Edge 500, an Elsa and a PT and have a good working knowledge of how they function and their capabilities. And yes, I am shopping for one more PM.

chaadster

Sorry if I put words in your mouth before; I had misunderstood you. Let me try to get it right:

Stages data quality isn't good enough to do aero and rolling drag estimations or FRC, but Powertap is.

Aside from the "why spend money doing simplistic training over uncomplicated terrain with a power meter when you can use a stopwatch and HRM" bits, is that an accurate takeaway of the relevant core of your comments?

RChung

Wait a second. I have more data than that, but you were the one who specified kilowatt sets. I was responding to the "how much variance in kilowatt sets" question. I answered appropriately: I don't know because I didn't see his data file but I know he found it more than he felt he could tolerate. Because of the cadence and single-leg measurement, even for a single rider you wouldn't be able to scale the variance up and down.

canam73

So just give me an example from whatever you have solid data on. As I said, I only picked 1000 because it is round.

RChung

Aero and rolling drag estimation and FRC are examples of things that require high data quality. Quantifying training load doesn't. There's a spectrum of things you do with a power meter that ranges from "not very demanding" to "very demanding." Every power meter has strengths and weaknesses. There's a spectrum on cost, there's a spectrum on reliability, there's a spectrum on data quality. When looking at a power meter, examine your use case and find the best match. There's a spectrum on the matches, and sometimes your best match may be the Stages, sometimes it may be some other power meter, sometimes it may be a wristwatch and a HRM. I can't tell you what your best match will be.