CycleOps Powercal - Power Tap heart strap power meter v Power Tap hub meter?

Discussion in 'Power Training' started by pcapetown, Apr 21, 2013.

  1. pcapetown

    pcapetown New Member

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    Hello to all.

    This is my first thread ...... I am just about to set up with a coach and he will be wanting to use power metering to train me. He is keen for me to buy a Power Tap hub power meter which is darn expensive. My local dealer has suggested I buy a Powercal, heart strap with power metering. This is the link to it: http://www.cycleops.com/en/products/power-meters/powercal.html . The heart strap has apparently calibrated heart rate with power for 1,000s of cyclists and is to within 5% accuracy of a hub meter.

    Now, here's the rub ...... The strap meter is about 1/10th the cost of the hub meter and wheelset. My to-be-coach says the strap is of little use for short road intervals. I am wondering whether to save money on the hub and to buy the strap and new racing wheels instead..... especially having raced this morning on a fast, lap circuit in no wind with factory specification wheels. I can use the strap on an indoor trainer, when training and racing with different wheels, and can hook it up with my Garmin Edge 500 (thoughts - assuming compatible - anyone had calibration issues?).

    As ever, your thoughts will be greatly appreciated.

    Thanks in advance,

    Peter
     
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  2. RapDaddyo

    RapDaddyo Active Member

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    A heart rate monitor is not a proxy for a power meter, even if the algorithm has been developed based on ride files from every cyclist on earth. If you don't want to spend the money for an actual power meter, you're better off using rate of perceived exertion (RPE) than a HR meter.
     
  3. An old Guy

    An old Guy Member

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    So you can afford a coach but not a power meter. PowerTap wheel cost about $600 used.

    Power meters are very useful in measuring power output, not so much as training aids.

    Heart rate monitors are very useful as training aids, not so much for measuring power.

    Using a power meter you kick your power up to a ceratin level and hold it there for some period of time.

    Using a heart rate monitor you kick your heart rate up to a certain level and hold it there for some period of time.

    ---

    I think you need to need to accumulate more money before you get involved in buying power meters, race wheels or coaching time.

    ---

    Many of the people here believe in training with power. They tend to give advice that matches that belief.

    I am a bit more agnostic. Most racers get by training with heart rate or just riding around. You might try that for a while. It is a lot cheaper.
     
  4. pcapetown

    pcapetown New Member

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    Thanks OG for this. I agree much of what you advise. Sadly, cycling equipment here costs almost double in the UK and Europe and there is no second hand market. Coaches are therefore relatively cheap. Peter
     
  5. bing181

    bing181 New Member

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    Well, without responding to the previous posts ....

    I have a Powercal. I don't have a Powertap, for exactly the reasons you've mentioned. On the other hand, I don't have a coach, and I don't race.

    My take on it is this. If you want to have some repeatable numbers to put into your Training With Power software (Golden Cheetah, WKO etc.), Powercal is fine. I can do the same route, at the same pace on consecutive days, have a quite different HR, but have Power totals/averages within 1 or 2 percent. So, as a global training tool, to go one step further than just HR or PE etc. and to give you metrics that you can use to manage your training load etc., it's fine. Even more than fine.

    But ... if you want to go out and do 20 minutes at 90% of FTP, let alone shorter intervals ... forget it. In fact, if you want to even look at what it's telling you as you're riding, pretty well forget it. It jumps around all over the place, and not by small amounts. It's only after the fact that it's useful. Even then, you have to take it with a grain of salt. On the other hand, it's the same grain of salt each time. In other words, if you averaged 200 watts one day, and for the same route, 205 watts the next day, then yes, you've increased your average watts by 2.5%. But you haven't necessarily put out 200W. It could have been 180W, or 220W. In my case, it reads over by about 20W at "normal" outputs, though from what I've read, if it's out, it's usually the other way.

    I'd be surprised if it were accurate enough while in use for a coach to work with. But perhaps you could try and see how you go. BTW, works seamlessly with and Edge 500.
     
  6. maydog

    maydog Well-Known Member

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    I have one, but now only use the power function for entertainment value for spin sessions. I suspects that it works "on-average" for most people because it was tuned / trained to the average cyclist (average size, power output) etc. I could make a random number generator that on-average spits out a power close to a riders average power - it may work just as well.

    http://www.cyclingforums.com/t/493454/chest-strap-power-meter-does-it-work

    Simply put, I have not found it useful for realtime or post ride analysis - I can not use it to pacing, straight HR and PE works better for me.

    As a heart rate strap it works great, good RF range and excellent battery life.
     
  7. joroshiba

    joroshiba New Member

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    Your +/- 5% number is garbage. That said I think the powercal is actually a great tool, and for only $50 more than a HR strap it is a good deal. It is not the equivalent of a precise and accurate direct force power meter though.

    I purchased a PowerCal literally the week they were available to bike shops, used it for 9 months before I got a Quarq. My FTP using the powercal was and remains 278w. In December when I got my Quarq my actual FTP was 200w, it is now ~235w (if you saw my previous post about not being able to push myself, it turns out I was just a wimp/holding myself back). The PowerCal was and still is useful for levels. That said the levels on the PowerCal for me do not correspond to the same percentages as published in TARWAPM. I had to set those based on perceived exertion and have since verified them with a PM, but it means that TSS and other such metrics will not come out the same as they should/are intended to. The real advantage over just a HR monitor is that (in my experience) it is more consistant, and responds far more instantaneously. You still need to look at all data through the scope of what your body is like though.
     
  8. Alex Simmons

    Alex Simmons Member

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    Putting aside whether it's a matter of belief (a strawman in any case), this is a power training forum, so what exactly do you expect people around here to talk about?
     
  9. danfoz

    danfoz Well-Known Member

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    What does this mean?
     
  10. An old Guy

    An old Guy Member

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    I used the phrase "training with power." That contrasts with "training with heart rate" or "training with perceived exertion." The forum title is intended to reflect a goal: developing power.

    One goal. Many beliefs.
     
  11. bing181

    bing181 New Member

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    No it's not.

    "This is the place to talk about training and racing with power (watts) measuring devices"
     
  12. joroshiba

    joroshiba New Member

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    For one, PowerTap stopped claiming that after they released the newest version last I checked, second if you look at my data, my powercal originally reported 28% off of what my actual power was and now that my fitness has increased it is 18% off. A device that the company itself cannot show changes in fitness is not going to be accurate.

    Their original marketing claim was +/- 10% and that was with a calibration procedure that is no longer possible, because they said it was too finicky and not enough people were doing it right and it was making the data less accurate at times instead of more.
     
  13. bing181

    bing181 New Member

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    I for one am having trouble following what you're posting. What is the 5% that you're referring to? There's no mention of 5% anywhere earlier in the thread, so .... ???

    Now you're introducing the above ... but in reference to what exactly? Once again, there's nothing in the thread that I can see in regard to any claim from Cycleops, so hard to see what you're referring to.

    Clarification?

    Getting back to the OP and the unit itself, there's a fairly comprehensive review here, which lays out the strengths and weaknesses. As a user, I'd agree with what he has to say:

    http://www.dcrainmaker.com/2012/11/cycleops-powercal-in-depth-review.html
     
  14. pcapetown

    pcapetown New Member

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    Thanks all for your advice and comment. The 5% figure, by the way, came from the Powercal site where a within +/- 5% error rate was used to derive power from heart rate. Nonetheless, the points above seem pretty telling: don't get a Powercal if you are going to be serious about using power for training and racing.
     
  15. joroshiba

    joroshiba New Member

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    Don't get the powercal and expect a power meter, it isn't one. They market it as one, but it does not do it. I wish they marketted it some other way, because I think people get hungup on this claim. It has a place and it works well for that place. If you read through their FAQ page it says:

    Quote: "In terms of changing fitness with a given individual our initial assumption was that yes, as fitness increased the user would need to re-calibrate to properly adjust the system but what the research shows is that these changes are relatively very small compared to other factors at play when using heart rate as the base measurement. In other words, the margin of error when using heart rate as the sole measure of exercise intensity is too great to accurately represent changes in fitness. " -- http://www.cycleops.com/en/faqs/powercal-faq.html
    In other words, it doesn't read changes in fitness which naturally means it isn't accurate. It is a great indicator of load on your body, it gives a readout in watts but I think people should think of numbers as "individualized exertion points." When calibrated properly and regularly I think it might give you a good power number, right now it is a good solid way to read exertion/stress in a more immediate form than with just a HRM.
     
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