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Garmin Forerunner 235 records 6% distance vs iPhone Runkeeper?

Former Member over 8 years ago

Hi,

I got my brand new Garmin Forerunner 235 this Thursday and I have taken a few runs with it. I notice that my Forerunner 235 measures about 6% longer distance than my iPhone 6 Runkeeper app that I have used for some years now. Here is one 5 km run with both measuring me, started close to each other:

Runkeeper: 5.12 km 26:35 time
Forerunner: 5.42 km 26:38 time

Forerunner adds an extra 6%, provided that Runkeeper is correct.

Anyone else noticed this?

Regards, Mikael
(Gävle, Sweden)

0 JamesAdkison over 8 years ago

If I was going to make a guess it would be that the watch is more accurate than your phone. However, neither of our guesses really matter.

Instead, run a known distance (e.g., on a track) and see which is measuring more accurately.

0 FlipStone over 8 years ago

First you really have to try multiple runs before drawing conclusions, also... Usually a watch is more accurate then a pone. As suggested, run a set out/fixed distance with both and compare.

Also, experiment with glonass on and off... It should improve accuracy but there are cases where it actually decreases it.

Can't you see by the plotted track if there is anything going on in either?

0 SciFish77 over 8 years ago

I've had my FR235 for about a month. Previously I was using RunKeeper on iPhone to store my runs. Now I'm using both.
RunKeeper consistently records longer distances, and therefore faster paces for me than my ForeRunner, so the opposite to you.
Phones are only as good as their GPS connections, so don't assume they're superior somehow. I've assumed the Garmin is more accurate than my phone. Another reason for that is that I often run a small lap in a park, and my friend does the same with a Samsung Galaxy and we recorded very different distances over a small lap between his Galaxy and my iPhone, both of us using RunKeeper! I got 460m on RunKeeper, he got 350m :eek: I then tried it with three other apps and got 440m, 420m and 400m :eek::eek: THAT told me a lot about the accuracy of phones and apps!
I've assumed that since my FR has GPS and GLONASS enabled that it will be more accurate. Although I'm also just thinking that it probably doesn't use both systems at once for increased accuracy, but rather has the option of joining one or the other as a way to speed up GETTING a connection, and not the quality of it or accuracy overall.

Regardless, the phones have proved themselves pretty lousy to me. Shame, because I'm a new runner and it turns out I'm even slower than RunKeeper had me believe :p

This morning I got:
4.23 km, 30:44, 07:16 min/km on RunKeeper
3.83 km, 30:11, 07:52 min/km on the ForeRunner

I believe the Garmin only.

0 DukeNukemmm over 8 years ago

This issue bothered me for quite a while actually - I used to record my run on several iPhone apps, and each will give me a different reading for the same course. Even the same app will give me different reading at different time!

But of course, not every phone apps are born equal. In my view, this is the list in terms of the accuracy of the apps
- Strava
- Run Keeper
- Nike Run
- MapMyRun (worst! constantly over-book the mileage and made me believe I was a super-runner and a star of the track, until the race day! :mad: )

They say the iPhone apps can be as accurate as the GPS chips inside. And the GPS chips inside an iPhone is no match (low grade) to the one in Garmin watch.

I've been running on a trail with fixed mile marker which I always calibrate against. So far I'm satisfied with FR235, it appears to be more accurate than most phone apps. However sometimes it's just slow in locating the GPS signal.

0 Nighthawk700 over 8 years ago

However sometimes it's just slow in locating the GPS signal.

Have you synced your watch with your phone before going into the Run/GPS mode? It preloads satellite information into your Forerunner which gives a faster GPS signal.

0 DukeNukemmm over 8 years ago

Have you synced your watch with your phone before going into the Run/GPS mode? It preloads satellite information into your Forerunner which gives a faster GPS signal.

Will try that trick next time. Thanks