GPSMAP 65s - GPS speed vs. Speed Sensor 2

Discussion related to the Garmin GPSMAP 65 series GPSr
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ewald.gruen
Posts: 74
Joined: Sat Jun 18, 2022 2:58 pm

GPSMAP 65s - GPS speed vs. Speed Sensor 2

Unread post by ewald.gruen »

Today I raced through the forest with the 65s on the handlebars at up to 33 km/h and later compared the GPS speed (calculated from the GPX file using a moving average and a 6-second window) with the speed measured by a Speed Sensor 2, and this is the result:

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               | Min Speed | Avg Speed | Max Speed |
GPS Speed      |      1.37 |     16.16 |     33.06 |
Speed Sensor 2 |      0.96 |     16.76 |     33.85 |
According to the header of the GPX file the maximum speed was 9.459 m/s (which equals 34.05 km/h):

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<gpxtrkx:MaxSpeed>9.459</gpxtrkx:MaxSpeed>
A detailed error analysis can be found in the appendix.

speed_comparison.png
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RickN55
Posts: 208
Joined: Fri Sep 30, 2022 2:24 pm

Re: GPSMAP 65s - GPS speed vs. Speed Sensor 2

Unread post by RickN55 »

So basically the Speed Sensor is a waste of money if you have a 65s? I looked at buying the sensor for my bike but didn't bother as the speed on the 65s seems to do the job.
GPSMAP 67, GPSMAP 65s (sold), GPSMAP 64s (sold), GPSMAP 62s, GPSMAP 60CSx, Edge 1040, Fenix 6x Pro (sold), Epix Gen2 Pro Sapphire 51mm.
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GPSrChive
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Joined: Fri Jan 20, 2017 11:29 pm

Re: GPSMAP 65s - GPS speed vs. Speed Sensor 2

Unread post by GPSrChive »

RickN55 wrote: Tue Feb 14, 2023 4:21 pm So basically the Speed Sensor is a waste of money if you have a 65s? I looked at buying the sensor for my bike but didn't bother as the speed on the 65s seems to do the job.
Waste? No.

Unnecessary for most people, probably yes.
RickN55
Posts: 208
Joined: Fri Sep 30, 2022 2:24 pm

Re: GPSMAP 65s - GPS speed vs. Speed Sensor 2

Unread post by RickN55 »

Well I tried a Speed Sensor 2 today. Nothing but issues. It connected to my 65s but it would work fine showing the speed then the next minute it would drop connection and the speed would show zero and the device would be "searching" for the speed sensor. Then it would work then it would do the same again. No idea what was up with it. I even put a new battery in to see if the battery was low on power but made no difference. So sent it back to Amazon..
GPSMAP 67, GPSMAP 65s (sold), GPSMAP 64s (sold), GPSMAP 62s, GPSMAP 60CSx, Edge 1040, Fenix 6x Pro (sold), Epix Gen2 Pro Sapphire 51mm.
0x01
Posts: 67
Joined: Tue Apr 13, 2021 2:13 pm

Re: GPSMAP 65s - GPS speed vs. Speed Sensor 2

Unread post by 0x01 »

Compared against an ordinary cycle computer manually calibrated by ruler, the GPSMAP 65s is extemely accurate (distance matching). I would not spend any money if you have a cycle computer already.
GPSMAP 65s | eTrex Legend HCx
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