Confused About Surge's Math When Displaying Distance vs. Step Count

[EnjoyToday]

Hello All!

I have a quick question about how the Surge calculates Distance vs. Step Count that I couldn't figure out. Hopefully you all know what I'm dloing wrong when trying to balance the books, so to speak.

Stride Length Setting multiplied by number of steps taken as shown on the tracker & dashboard does not match the distance displayed on the tracker & dashboard. I'm getting free steps on the dashboard.

On my settings, Walking Stride is 2 feet 3-1/2 inches and Running is 2 feet 10 inches.

Treadmill Run Example-

For a Treadmill Run of one mile, the distance shown on the tracker calculated to just over 2 feet 0 inch for my stride. This misses my set stride of 2 feet 10 inches by nearly 10 inches.  The step count at one mile should have been 1865 for my running stride length setting.

My Math:

The tracker showed 1.0 mile and 2551 steps.

<5280 Feet-Per-Mile divided by 2551 Steps Displayed equals 2.069 Stride Length As Calculated By Surge>

 I repeated the test & got the same result to within 12 steps on the count. The next day I did a reset of the device & got the same results (within 15 steps counted)

For a GPS walk of 1.21 miles, the stride calculated to 2 feet 2-1/2 inches, which is closer to my 2 feet 3-1/2" walking stride setting than the treadmill was with my running stride.

(5280 Feet-Per-Mile times 1.21 Miles-Walked divided by 2890 Steps Shown on Dashboard equals 2.21 feet or 2 feet 2-1/2")

Am I doing the math wrong or does Surge have a different stride length for Treadmill & GPS walks that I haven't found?

Thanks for helping me figure this one out!

Enjoy This Day,

Paul

[SunsetRunner]

When I run on my treadmill for 36 minutes (my average 4.0 mile "Free Range" time), my treadmill reports I've only run ~3.3 to 3.4 miles. Same intensity, same heart rate, but grossly different distance.

So, maybe, it is you who has a different stride length when running on the treadmill versus walking with the GPS on. Perhpas you did actually have a stride length of only 2 feet? The only way to really know is to physically measure the distance as you are running - which is difficult to do alone - on the belt as it rotates at whatever speed.

Also, if you're going to test this, it should be apples to apples. Both runs, or both walks, not one versus the other. Too many variables.

[EnjoyToday]

Hi ZenGardener

Thank You for taking time to reply to my question. I sure appreciate it!

I'm really, really new to Fitbit, so I'm learning as I go. (And, I'm enjoying every minute of it.)

I didn't phrase my question very well at all. My head counted steps match the Surge display of steps taken while on treadmill runs. I did this by cheating my actual length down in my settings (Lots of trial & error test runs).

I have it easy measuring my stride because my treadmill isn't motorized. My feet rotate the belt as I run. I can watch a measure mounted on the side rail & see where my feet land & rise.

The quesiton's really about how Surge calculates its Dashboard Report distance to steps ratio.

Here's where their math doesn't make sense to my brain:

My running stride is set to 2 feet ten inches in Fitbit.

On the Dashboard, a sample report says 1 mile in 2551 steps.

Dividing their reported one mile by their reported steps taken:

     5280 feet by 2551 steps equals a stride of 2 feet 3/4"

Therefore, Dashboard & Surge aren't using my stride length as pre-set in Settings.

Since my step head count matches the Surge display at 2551 steps taken (+/- 5 or 6 steps), I actually went 1.37 miles using my set stride of 2 feet ten inches. (To confuse it more, I actually went farther because I had to cheat my stride lower to make my actually counted step count match the Surge step count.)

Shouldn't the number of steps shown for a 1 mile run on the dashboard be 5280 divided by the stride length in the settings?

I'm just curious how the math works. I'm sure it all makes sense, but I sure can't figure it out.

Thanks Again for replying!

Paul

[SunsetRunner]

Well, the math is correct, but I can't speak to why the Dashboard - or the Surge - is reporting the way it is. Of course, your walking stride will be much shorter than your running stride, but you shouldn't see this kind of error if you're running (or walking) in both tests.

It is curious because mine does not report in error. My stride length is (set to) 3' 4". I ran 10 miles (9.97 per the GPS) on Sunday, and the Surge step count reported to the Dashboard was 15,716 steps. (9.97mi * 5280ft/mi) / 15716 steps = 3.35 feet, or 3' 4.19". This consistantly calculates correctly (within an acceptable margin of error) for each run I have done - regardless of length.

[EnjoyToday]

Thanks for confirming my calculations, ZenGarner.  Math & I often don't play well together.

Thanks, too, for checking your own Dashboard vs. Stride length.

I'm wondering if my Surge has an internal brain error & needs some reprogarmming.

It has a few other goofy traits; such as GPS usually being way far from where I actually was & reporting much less or much more distance than I actually traveled, battery life of 1 hour maximum with GPS.  It has a few minor annoyances, too. The ones that are most pesky are that I have to tape the charger plug to the Surge to keep it connected & in order to sync, the tracker has to be within an inch or 2 of the dongle or it is not found.

Considering how much technology is packed into such a small space, I'd say the unit is pretty amazing! (But I went to school in the slide rule days, so technology is always a marvel to me!)

Perhpas is it time for a tech support phone call.

Thanks Again for stepping up and helping. I do appreciate your advice & efforts!

Enjoy This Day!

Paul

[11butterscotch]

Sometimes the device errors between walk vs run. Set walk and stride settings to the same distance to negate this variance.

[11butterscotch]

BTW u don't need to count in your head, that only checks against step count. Whatever the tracker states for step count multiply against single walk/stride length and should equal distance in dashboard.

[EnjoyToday]

Thanks for writing 11Butterscotch. I sure appreciate your help and advice.

I didn't write my question very clearly at all. Sometimes I'm kind of crummy at expressing things in writing. I'll never make it as a Hallmark Card writer!

The problem isn't really that the step count doesn't match my head count, as it does match within a few steps. (After lots of trial & error tweaking.)

The real problem is that what the tracker sates for step count multiplied against single walk/stride length (or run/stride length) doesn't match the distance in dashboard. Even the dashboard step count multiplied by the single walk/stride length (or run/stride length) doesn't match the distance in dashboard or on the tracker itself. Their math is goofy. I wonder what they are using for my stride?

I tried your suggestion about setting walk & run to the same stride.  Unfortunately the error continues.

At this point, with all the other problems I'm having with this tracker, I may  have to return it & re-think this purchase. The problems are getting kind of frustrating.

Thanks Again for taking time to write with your idea and explanation.

Be Sure to Enjoy This Day!

Paul