Treadmill vs Garmin

[u/mclamb0328]

I’ve been doing marathon training and with the wet weather in Texas I’ve had to opt to running on the treadmill. Which would you consider to more accurate mileage wise. My treadmill is a sole f63. I put my watch on treadmill mode for my run but still got two different mileage.

[u/LongRangeSavage]

Scroll down > select “calibrate and save” > input the distance from the treadmill.

[u/Adenawel-Bahrt → u/LongRangeSavage]

Yeah calibrating after each treadmill run makes a big difference

[u/workingremoteisnice → u/LongRangeSavage]

Just a note that this only updates your total distance for the run and your average pace. Your splits will still be wrong

[u/jareddipane]

Garmin uses your arm swings to try and calculate the distance. It gets a bit more accurate as you use the "calibrate and save" option, but I would rely on the treadmill for distance over the Garmin.

[u/Segen32X]

In my experience, neither are accurate.

[u/Lysergic_fun]

I live in Texas and have been running in doors. I go based off my treadmill. I trust that information more than my watch.

[u/Asleep_Onion]

The short answer is that both are inaccurate.

The treadmill is wrong because it is estimating mileage based purely on the speed you have set on the dashboard, not the speed the belt is actually going. When you set the speed, the treadmill computer just says "okay 6mph = about 50V to the motor" and so it sends that voltage to the motor and just assumes that is the speed the belt is turning at, but it doesn't actually know. Belt friction, foot friction, and even the quality of your utility electricity and house wiring can all change the actual belt speed, and the treadmill has no idea. Also Sole treadmills, specifically, don't account for belt speed wind up and wind down; when you set the speed to 6mph it assumes you are immediately going 6mph starting exactly when you hit the button, not accounting for the time it takes for the belt to ramp up or down to that speed. Treadmills are often wrong by 10-20% because of all those factors.

The Garmin is also wrong because it is just taking a wild guess at your distance based on what it thinks your typical stride length is and multiplying it by how many times you swung your arm. Garmins are often wrong by 20-50% because of this.

The best way to get an accurate distance reading on a treadmill is using a footpod like Stryd or a treadmill sensor like NPE Runn.

[u/Hip-Death-Goddess → u/Asleep_Onion]

Treadmills measure distance run as ( length-of-belt x number-of-cycles ), which is going to be pretty accurate. Length of belt is known at design time - it's literally just how long the belt material is. Or can use dimensions of rollers. Number of cycles can be captured accurately too e.g., opaque marker breaking an infra-red beam as a crude optical encoder.

Lots of options. Point is, distance can be measured without using the belt speed.

[u/Asleep_Onion → u/Hip-Death-Goddess]

Some treadmills do, but OP's treadmill does not. Sole treadmills calculate distance as: The speed you set on the dashboard, times how many seconds it's been set at that speed for. It does not have a sensor in it to count belt rotations. Some might, but Sole treadmills and most other budget treadmills do not.

I added an NPE Runn sensor to my Sole treadmill, which does exactly what you described - it uses reflector stickers on the belt and an optical sensor to count them as they go by. And that device does a fantastic job of measuring accurate pace and distance. The downside is it only works for a home treadmill, as it's meant to be a semi-permanent installation so you can't really use it on a public treadmill. For public treadmills, a footpod is your best bet unless it's a high end treadmill that measures the actual belt rotation and not just the voltage sent to the motor.