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Stryd is not all it's cut out to be...maybe

Dr Phil
over 4 years ago

This morning I ran twice with one watch hooked up to a Stryd and set to Always use for Pace and Distance and another just on GPS. In both cases the Stryd came up with a longer distance. First up was a trail run that we've been running for years so we know it is close to 9km. Stryd returned 9.31 where my GPS Trail Run gave 8.99 and my wife's 945 8.97km. Next up was parkrun. For those who don't know, parkrun is always 5km. Our parkrun has been accurately measured using a calibrated wheel so we know it's 5.04km from the wheel. And every GPS run we've done has been 5km +/-20m or so. This morning Stryd gave 5.24km while the GPS watches gave 5.02 and 5.01 respectively.

This wasn't the first time out with the Stryd. Several runs on a 400m track and a couple of other trails runs should have seen it calibrated by now. I haven't looked over earlier runs as I did want to make sure I had a number of different runs with the Stryd.

Let's see how things progress. I have done a couple of runs on a 400m track but not sure if I had the Stryd set up properly so can't comment on that except to say the watches gave the same distance. However, I now have the Stryd where I want it so can. and will, do some more comparison runs to see how this plays out.

  • 0 over 4 years ago in reply to Former Member

    They said that. They were even arguing against people that only a few people are affected. They declined Threads where people were asking about „what calibration factor do you have?“ because they know That it’s the opposite. I know lots of Stryd users in real. But no one has a calibration factor +-1%. And it’s Bad. Yes. Because people are believing in that and they they got very bad results for their run. My marathon was 40.8k long. That never happened to me before. No apologize from then. Nothing. That’s bad customer service

  • 0 over 4 years ago in reply to Realworldrunner

    The problem is that it seems a lot of people find it inaccurate and need to caliberate it - this constrasts what they say on marketing and indeed on the back of the box! Sorry, but exceeding 'the precision of GPS' is complete nonsense. OK, there may be examples when it does (Urban Canyon), but it certainly does not with clear open skies.

    So...if you need to calibrate it as you do with other footpods, then IMHO the Zwift / Milestone footpods at around 20% of the cost is just as viable. Unless you need power (which frankly seems to be as much use as a chocolate teapot)

    Certainly for a half marathon I have coming up in September, I WILL NOT be using the Stryd as if it runs true to form, it'll come up around 2-3% short. I have had some luck calibrating (up to a point), but my pace is quite inconsistent and my course is hilly, both of which seem to throw it off.

  • 0 over 4 years ago

    The main advantage of a Stryd is smooth instant pace, not accurate total distance.

  • 0 over 4 years ago in reply to subra

    But if it cannot measure distance accurately then pace will be wrong.

  • 0 over 4 years ago in reply to 5135968

    Note Stryd mention precision not accuracy. They are very different in meaning. There’s little point being precisely inaccurate.

  • 0 over 4 years ago in reply to Dr Phil

    Is it still a good precision for a runner when I have very different and more bad precision when I am changing shoes? I think it’s not true 

  • 0 over 4 years ago in reply to Dr Phil

    If you’re precisely inaccurate, then all you need to do is calibrate. That is how you sight in a rifle scope.

    In my experience, Stryd is more precise than GPS, but I think that depends on the device being very securely attached to your laces (no wiggle when you tug at it) and to a lesser extent using a consistent pair of shoes.

    PS: How to calibrate Stryd... the little details matter... support.stryd.com/.../115004337834-Distance-and-Calibration

  • 0 over 4 years ago in reply to Dr Phil
    Dr Phil said:
    But if it cannot measure distance accurately then pace will be wrong.

    A Stryd analyzes the kinematics of a step with accelerometers and calculates the speed using the equations for projectile motion from physics.

    en.wikipedia.org/.../Projectile_motion

    It is already known that this method is accurate and precise for one shot, but not for a long distance with many subsequent shots. So Stryd usually shows a more accurate and precise and smooth instant speed than GPS, but cannot show a more accurate and precise total distance because of the summation of the calculation errors for each step. Especially if running with variable speed on changing ground.

  • 0 over 4 years ago in reply to nonparametric

    To put it into perspective I agree with Tim with his testing of the Stryd pod. I do recommend them but you need to calibration your pod as the out of box calibration is all of the place, once calibration it for the shoes you wear it’s consistent and accurate - well for me. 

    take a look at his YouTube testing 4 Stryd, two per shoe without calibration on a treadmill in Zwift https://youtu.be/cMsru129e3c but calibrate on the road/track not a treadmill.

    I find generally my non carbon shoes regardless of brand, stack heigh and drop have a the same calibration and the vaporfly and some other carbon shoes are a completely different calibration but each very similar by +/- 0.1