Indoor, gym training, treadmills etc., distance not even close to being accurate

We used to be able to set our own stride length in the Garmin settings so that treadmill distance matched what we actually ran. This needs to be reinstated as a feature.

I have relatively short legs, 29" inseam, yet the only option the device gives is to set a distance based on step count, not on actual leg measurements. This is a significant limitation for accurate treadmill tracking.

Right now my Forerunner 255 consistently records treadmill distance up to 30 per cent less than the distance shown on the treadmill console. I am fully aware of the need to keep my arms moving to ensure step count accuracy, and I do so, but this does not resolve the discrepancy.

Most treadmill users know that the treadmill display provides a reasonable reference for distance. Many runners calibrate their treadmill or check belt length and running deck measurements to ensure accuracy. Even with those checks, some variation between treadmill distance and wrist-based sensors is expected, but allowing users to manually adjust stride length—either at setup or after the workout—would bring recorded distance in line with the actual effort. This would also improve other metrics such as pace, calories burned, and overall workout data quality.

Other brands already allow users to set their own stride or manually correct treadmill distance after a run. Garmin should offer the same functionality. If we can edit laps and GPS tracks for outdoor runs, treadmill workouts should not be excluded from this capability.

For transparency, I did calibrate the 255 with my treadmill on first use and have attempted recalibration multiple times since, with no meaningful improvement.

Please reinstate the ability to set a custom stride length or add an option to manually adjust treadmill distance after each workout. This would make treadmill training far more accurate, consistent, and useful for serious runners and gym users alike.

Thank you for considering this request.

  • When I run on a treadmill, I run around 180 steps per minute regardless of whether I am running 9 km/h or 18 km/t. A fixed stride length makes no sense. If I run fast, my stride length is more than double of what it is if I run slowly. The watch is supposed to measure how vigorously I am running based on the accceleration of my arm swing. Not only the frequency. It is supposed to calibrate the parameters when you do outdoor GPS runs, so that it can recognise the different running speeds.

  • Your own explanation actually proves why user set stride length defeats the system.

    Stride length is not a fixed input. It is an output. It changes continuously with speed, fatigue, incline, cadence drift and running mechanics. Locking it in manually assumes a constant relationship that does not exist, especially when cadence stays near 180 across a wide speed range.

    Garmin and similar watches do not calculate treadmill pace as cadence × fixed stride length. They use accelerometer data from the arm to estimate speed. That includes vertical and horizontal acceleration, impact force and swing dynamics, not just step frequency. Outdoor GPS runs are then used to calibrate those motion patterns against real speed.

    If you allow the watch to learn those patterns, it can infer that higher acceleration amplitude at the same cadence equals higher speed. The moment you force a fixed stride length, you override that learning and reduce the calculation to a crude cadence multiplier. That is why manual stride length makes accuracy worse, not better.

    In short
    Stride length is variable, not configurable
    Cadence alone is insufficient, which Garmin already accounts for
    GPS calibration trains the motion model, not a fixed stride number
    Manually setting stride length removes the very adaptation you are asking for

    So yes, your point about cadence staying constant is valid, but it is precisely why stride length must not be user locked. The watch needs freedom to model it dynamically.

  • In my case the estimation of treadmill distance is fairly good if I run at moderate speed. The watch does however understimate my speed when I run fast, and overestimate my speed when I run slowly. It does not seem to be able to model how much I change my stride length with speed.

    My Garmin chest strap with running dynamics is actually even worse at this.