Forerunner 945 concern about distance accuracy

I observed the same issue long time ago with this watch. At some point I bought a cheap foot-pod (Adidas Mi Coach, I paid ~10USD) and after calibration it improved the accuracy and consistency of the distance (and pace) measurements.

Here are the results of some quick benchmarks I did: https://github.com/filipsPL/gps-accuracy

I tested it also on treadmills and the accuracy is super good (after calibration).

Currently I'm using a Stryd, but there is no additional benefit in terms of distance accuracy.

GPS watches and runners themselves (tangents, aid stations, dodging, etc) are not that accurate... to be within a half of a percent error is to be expected.  Doing 'update distance' on Strava will result often in added distance of easily 1% just based on algorithm and how they recalculate the distance based on the GPS data.

Hello friend! I found on my local store Adidas Mi Coach for 22€ and wanted to pair it with 945.

My current setup is 945 Gps+ Gallileo  1s paired with Polar H10 via Ant+ and Garmin Running Dynamics Pod. Never missed a bit.

I want to purchase Adidas Mi Coach for better distance tracking and wanted to ask you: when i start an activity i pair automatically sensors like Hr and Pod. Also i pair my headphone via bluetooth and wait 2 minutes after gps lock to find more satellites. Sometimes i saw gps drift sometimes is good enough. I want to pair Adidas and start running so simple? Does it override gps speed like speed cadence sensor do on my cycling setup? Garmin Edge 520 paired with Speed and Cadence ans just Gps for tracking.

Version 13 on firmware. Do you thing Adidas Mi Coach will help provide better distance pace?

Thanxs a lot a rode your review but you were on treadmill and track run i want it for daily runa.

Just to be clear - I've tested this for the treadmill running and for regular outdoor running. In both cases it gave me good results.

In practice it works as Edge+Sensors, but first  you have to set up your forerunner to read speed and/or distance from the pod. basically you can start your run as soon as the sensor is detected (which is the matter of seconds).

How do you set up speed or cadence? I know that 945 does cadence from wrist but its is inaccurate so connecting Garmin Running Dunamics Pod reads cadence from there!

If i purchase Micoach or Garmin Footpod will be

Candence info Pod<Micoach Footpod<945

tI just confirmed from Garmin support that if i purchase Footpod cadence info will be transmitted from RD pod and not from footpod but i do noy care about cadence but for accurate distance and pace.

Please keep in mind on treadmill sure you might miss some cadences/steps because of changing music/wiping sweat / playing with treadmill buttons... so a footpod will help. 

HOWEVER... your pace/distance estimate on treadmill is an estimate!  It is based on your SPM corelating to a certain pace.  BUT- cadence and pace are not linear or consistent (similar to HR at #:## pace)!!!  For instance my warmup on Tread this morning at 7-8mph was at 177-185spm, then I ran uphill 8.6mph 3% and 5%... cadence was a pretty steady 196 , then I slowed down to 8.5 and 2%... still 196 .... then 'recovery' 186spm (7-8mph)... So not a real great correlation of pace and SPM in my opinion.  Plus treadmill running / slope effects cadence and mechanics quite a bit.

When I run outside I have a very small difference in SPM once over or near Marathon pace... as well as very small difference in on easy runs.  Looking at recent history my cadence for paces of 8:00 to 9:20/mile... are 187 to 179.... with many of the runs +/-7spm for same/similar paces...  makes 'treadmill' run estimating impossible (see SPM/paces above).

If you are hoping your footpod is going to be better than GPS (the original issue(?)).... definitely not.  Not even close

I do not run on treadmill so i do not care much.

I need more accurate data when running outside and i cant rely on Gps i found out when running on town to get out of town was running on steady pace and Garmin reads more or less and then out of town when Gps reception is better pace is better too. 

Also from Garmin support said Garmin footpod can override Gps for distance and pace if you set it from sensors.

Running indoors helps a lot but have done zero workouts lol.

1. Select your foot pod.
2. Select Speed or Distance.
3. Select an option:

   • Select Indoor when you are training with GPS turned off, usually indoors.

   • Select Always to use your foot pod data regardless of the GPS setting.

1. Select your foot pod.
2. Select Speed or Distance.
3. Select an option:

   • Select Indoor when you are training with GPS turned off, usually indoors.

   • Select Always to use your foot pod data regardless of the GPS setting.

It is like Edge + sensors correct! Can you do that with Adidas MiCoach or it is better to purchase Garmin footpod?

Any Garmin I have used has worked sort of in downtown major cities (Boston , Minneapolis, Chicago, Paris, London) ... yes it might put me on the wrong side of street on the map, or have hickups in pace or location... but all in all for Marathons and training runs... have "worked", distance for a lap might be off by 5-10%, but overall the run is pretty spot on (26.28 to 26.48miles)  Yes I have seen some bad maps of others in Chicago marathons with zigzags (blocks over!) and I have seen it myself on city walks... or tunnels... but rare.  So maybe your watch is broken :-/ 

To use your GPS watch in a "indoor run mode" (using cadence, not Gps) in a town with giant tall buildings / skyscrappers..., could or could not be more accurate and maybe, just kind of a gamble.  IF you always run at same pace that you and your cadence and watch are calibrated too... probably decent.   Like when I run on the treadmill at a flat and aerobic easy pace... 10km might be 9.9 or 10.1km... great.  BUT... if I do a lot of zone4-5 or lots of inclines of 4-8% or 15%... might be 8.5 to 11.5km

However, mixed terrain, hills, mixed pace... using cadence for pace/distance travelled outside of a town - is crazy IMO.  but if you feel better about it, go for it , but it is off as much or more than your GPS for sure unless you are running short runs and never change pace or surfaces or wind...etc. 

Using cadence only is like the old saying... "Even a broken clock is right twice a day! "