I have weeks of outdoor runs and the accuracy outdoors seems fine. My device has trouble having any idea of my pace on the tread mill I had it set on 7.5 for almost an hour and my fenix thought I had run 6.3 when in reality it was closer to 7.1 miles. Is this normal? Would a foot pod make a difference? I have RD pod on for more than 20 outdoor runs and thought it would improve the treadmill accuracy but it didn't actually may have made it worse.
yes it is normal - it is not easy to track distance on a treadmill with something only mounted on your arm.
I use both Garmins foot pod and the STRYD footpod.
Stryd is by FAR the most precise for treadmill usage.
It will NOT 100% match your treadmill indication as the treadmill's are usually a slight bit off - and is not super at registering the small slowdowns that might happen when your feet lands.
Today I did a 12 km treadmill run - and initial offset was 30m (treadmills start slow - so foot pods have hard time at slow speed) - and Stryd offset after 12km was 100 meters total. So I ran 12.1km according to treadmill.
So 70m "wrong" over 12km is not bad. Stryd is NOT calibrated.
Apart from that Stryd acts as a power meter - which might help some people develop better running style. But you can't beat it as a footpod!